Caffeine
11 benefits mapped to clinical evidence across supplements.
Dose per serving from products
1,641 products in our catalogue print how much Caffeine a serving holds.
Most common: 100 mg to 250 mg, 41% of 1,641 products.
| Dose per serving | Products |
|---|---|
| 10 mg or less | 54 |
| 10 mg to 25 mg | 85 |
| 25 mg to 50 mg | 236 |
| 50 mg to 100 mg | 394 |
| 100 mg to 250 mg | 679 |
| 250 mg to 500 mg | 179 |
| over 500 mg | 14 |
Dose per serving from research
485 study groups in 306 studies say how much Caffeine participants took a day.
These are the doses the studies gave. They are not a recommendation.
Most common: 100 mg to 250 mg, 40% of 485 study groups.
| Daily dose | Study groups |
|---|---|
| 25 mg or less | 11 |
| 25 mg to 50 mg | 23 |
| 50 mg to 100 mg | 88 |
| 100 mg to 250 mg | 193 |
| 250 mg to 500 mg | 117 |
| 500 mg to 1 g | 48 |
| over 1 g | 5 |
Commonly used together
114 of 765 study groups took Caffeine with something else. Shown: what 3 or more different studies gave. The 10 most common of 18.
What was given together, not what works together.
| Taken with | Study groups |
|---|---|
| ephedrine | 17 |
| Green Tea Extract | 10 |
| Chlorogenic Acid | 9 |
| Vitamin B12 | 9 |
| Beta-Alanine | 8 |
| Epigallocatechin Gallate | 8 |
| Niacin | 8 |
| L-Tyrosine | 7 |
| Taurine | 7 |
| Creatine | 6 |
Benefit Evidence
Caffeine: faster attention +RT
Drunk: partial RT rescue
Sleep loss: alertness +RT
Reaction time + mood
Memory/attention + endurance
Driving/sport speed +10%
Caffeine: faster attention +RT
Drunk: partial RT rescue
Sleep loss: alertness +RT
Research sources
Alertness (113)
- The acute physiological and mood effects of tea and coffee: the role of caffeine level
PubMed ID: 10837840
Caffeinated tea/coffee acutely increased alertness/energetic arousal in randomized crossover experiments.
- Sleep loss and temporal memory
PubMed ID: 10718074
Caffeine reduced subjective sleepiness after 36 h awake, indicative of wakefulness-promoting action.
- Caffeine attenuates vasovagal reactions in female first-time blood donors
PubMed ID: 10431942
250 mg caffeine before blood donation reduced faint/dizziness reactions and increased willingness to donate again—consistent with acute alerting/agonizing effects.
- Mood and psychomotor performance effects of the first, but not of subsequent, cup-of-coffee equivalent doses of caffeine consumed after overnight caffeine abstinence
PubMed ID: 9862086
After overnight abstinence, caffeine produced rapid increases in energetic mood and psychomotor speed consistent with faster wakefulness.
- Caffeine deprivation affects vigilance performance and mood
PubMed ID: 9811379
Habitual-morning caffeine abstinence reduced vigilance (targets detected/RT), indicating caffeine supports task vigilance.
- Caffeine withdrawal symptoms following brief caffeine deprivation
PubMed ID: 9402612
Withdrawal-induced sleepiness implies caffeine promotes wakefulness in regular users.
- Illustrating caffeine's pharmacological and expectancy effects utilizing a balanced placebo design
PubMed ID: 8991966
Caffeine increased pulse and BP and both ingestion and expectancy altered mood/performance ratings (supports alerting/arousal effects).
- The effects of caffeine on simulated night-shift work and subsequent daytime sleep
PubMed ID: 7761739
Nighttime caffeine reduced physiological sleep propensity during simulated night shifts.
- The use of caffeine versus prophylactic naps in sustained performance
PubMed ID: 7792499
Large randomized study found caffeine improved alertness vs placebo/naps during sleep loss.
- An auditory attention task: a note on the processing of verbal information
PubMed ID: 8022682
Caffeine produced clear performance improvements after prolonged wakefulness—strong evidence for faster/robust wakefulness in sleep-deprived subjects.
- Influence of caffeine on information processing stages in well rested and fatigued subjects
PubMed ID: 7862853
Caffeine shortened RTs and increased cortical arousal and perceptual sensitivity — benefits for sustained vigilance, especially when fatigued.
- Does caffeine intake enhance absolute levels of cognitive performance?
PubMed ID: 7870897
Habitual caffeine associated with better reaction and cognitive test performance relevant to vigilance.
- Caffeine reversal of sleep deprivation effects on alertness and mood
PubMed ID: 7871042
Large randomized trial showing high‑dose caffeine after prolonged wakefulness robustly increases alertness and reduces sleepiness.
- Effects of breakfast and caffeine on performance and mood in the late morning and after lunch
PubMed ID: 1299795
Demonstrated increases in subjective alertness and multiple attention/ cognition measures after caffeine (robust evidence).
- Daytime sleepiness, performance, mood, nocturnal sleep: the effect of benzodiazepine and caffeine on their relationship
PubMed ID: 2184488
Caffeine reduced the negative impact of sleepiness on performance, supporting vigilance.
- Separate and joint effects of alcohol and caffeine on conflict monitoring and adaptation
PubMed ID: 26815360
Caffeine altered conflict-monitoring ERPs and sped responses, consistent with improved vigilance/ sustained attention capability.
- Effects of caffeinated vs. non-caffeinated alcoholic beverage on next-day hangover incidence and severity, perceived sleep quality, and alertness
PubMed ID: 24090620
Calibrated caffeine in beer slightly improved morning alertness/perceived sleep quality — supports faster wakefulness on waking.
- Effects of caffeine and alcohol on mood and performance changes following consumption of lager
PubMed ID: 23377024
High caffeine dose removed alcohol-induced drop in subjective alertness — supports restoration of wakefulness.
- Genetic determinants of blood pressure responses to caffeine drinking
PubMed ID: 22170367
Acute caffeine (3 mg/kg) raised plasma adrenaline and modestly increased BP — physiological arousal consistent with alertness.
- Caffeine expectancies influence the subjective and behavioral effects of caffeine
PubMed ID: 19760283
Strong improvements in vigilance reaction time and accuracy after 280 mg caffeine (robust vigilance evidence).
- Situational insomnia: consistency, predictors, and outcomes
PubMed ID: 14746386
400 mg reduced sleep efficiency and increased sleep latency/next-day wakefulness in susceptible subjects.
- Interactions between alcohol and caffeine in relation to psychomotor speed and accuracy
PubMed ID: 12404692
Improved psychomotor speed and partial error reduction under alcohol indicate better vigilance for task elements.
- Subjective and objective effects of coffee consumption - caffeine or expectations?
PubMed ID: 25481367
5 mg/kg produced objective autonomic activation and altered subjective arousal reports.
- Acute personalized habitual caffeine doses improve attention and have selective effects when considering the fractionation of executive functions
PubMed ID: 26621326
Morning personalized caffeine lowered fatigue and improved attention, consistent with increased subjective alertness.
- Caffeine intake is associated with pupil dilation and enhanced accommodation
PubMed ID: 27983733
Rapid physiological markers of arousal (pupil dilation) after 250 mg indicate quick wakefulness/alerting effects.
- Effects of a single, oral 60 mg caffeine dose on attention in healthy adult subjects
PubMed ID: 27649778
60 mg improved sustained-attention (vigilance) tasks (Mackworth Clock and RVIP) in healthy adults.
- Investigating the effects of caffeine on executive functions using traditional Stroop and a new ecologically-valid virtual reality task, the Jansari assessment of Executive Functions (JEF(©))
PubMed ID: 27215836
Caffeinated coffee improved several executive and attentional tasks and sped reaction time—evidence for improved task vigilance in real-world tasks.
- Caffeine affects cardiovascular and neuroendocrine activation at work and home
PubMed ID: 12140349
Sustained sympathetic activation after 500 mg supports quicker physiological wakefulness during daily activities.
- Effect of three caffeine doses on plasma catecholamines and alertness during prolonged wakefulness
PubMed ID: 11151742
Clear, dose-dependent objective and subjective alertness improvements and faster reaction time.
- Effect of Alpinia galanga on Mental Alertness and Sustained Attention With or Without Caffeine: A Randomized Placebo-Controlled Study
PubMed ID: 28910196
Study reported modest alertness increases with Alpinia galanga and a caffeine-containing composite.
- Effect of single caffeine intake on neuropsychological functions in healthy volunteers: A double-blind placebo-controlled study
PubMed ID: 30379815
200 mg improved executive scores and shortened braking reaction time, consistent with increased alertness.
- The Acute Effects of Caffeinated Black Coffee on Cognition and Mood in Healthy Young and Older Adults
PubMed ID: 30274327
100 mg regular coffee increased subjective alertness and improved attention measures vs placebo.
- Using coffee to compensate for poor sleep: Impact on vigilance and implications for workplace performance
PubMed ID: 29866304
100 mg coffee sped reaction time and stabilized RT over time — hallmark alertness effect.
- Influence of genetic polymorphisms and habitual caffeine intake on the changes in blood pressure, pulse rate, and calculation speed after caffeine intake: A prospective, double blind, randomized trial in healthy volunteers
PubMed ID: 30773300
Faster calculation speed implies improved sustained task performance and vigilance.
- Cognitive enhancement effects of stimulants: a randomized controlled trial testing methylphenidate, modafinil, and caffeine
PubMed ID: 33201262
PVT reaction time decreased by ~13 ms after 200 mg caffeine (improved sustained attention/alerting).
- Expectation for stimulant type modifies caffeine's effects on mood and cognition among college students
PubMed ID: 33734725
200 mg caffeine reliably increased subjective feelings of stimulation/alertness vs placebo.
- The Effects of Intraoperative Caffeine on Postoperative Opioid Consumption and Related Outcomes After Laparoscopic Surgery: A Randomized Controlled Trial
PubMed ID: 33939649
Intraoperative caffeine associated with EEG signs of faster neurophysiologic recovery and less early delirium — implies faster return of wakeful brain activity.
- Effects of Daily Matcha and Caffeine Intake on Mild Acute Psychological Stress-Related Cognitive Function in Middle-Aged and Older Adults: A Randomized Placebo-Controlled Study
PubMed ID: 34067795
Acute caffeine shortened reaction times and improved simple attention measures — classic alerting effect.
- Acute cognitive performance and mood effects of coffee berry and apple extracts: A randomised, double blind, placebo controlled crossover study in healthy humans
PubMed ID: 34380382
Coffee-berry extract increased arousal/alertness (but contains polyphenols; caffeine role uncertain).
- Genetic Determinants of Neurobehavioral Responses to Caffeine Administration during Sleep Deprivation: A Randomized, Cross Over Study (NCT03859882)
PubMed ID: 33920292
Caffeine reduced PVT lapses and EEG theta increases during 38 h wakefulness—robust preservation of vigilance with genotype interactions.
- Caffeine selectively mitigates cognitive deficits caused by sleep deprivation
PubMed ID: 34014758
Large RCT: caffeine reliably restored vigilant attention (PVT) after sleep deprivation—strongest evidence for vigilance benefit.
- Cognitive enhancement: Effects of methylphenidate, modafinil, and caffeine on latent memory and resting state functional connectivity in healthy adults
PubMed ID: 35670369
Single‑dose stimulants including caffeine improved memory/attention metrics consistent with better vigilance.
- Caffeine and attentional control: improved and impaired performance in healthy older adults and Parkinson's disease according to task demands
PubMed ID: 35006304
100 mg improved certain attention measures after withdrawal, consistent with enhanced vigilance in some tasks.
- Effects of caffeine, methylliberine, and theacrine on vigilance, marksmanship, and hemodynamic responses in tactical personnel: a double-blind, randomized, placebo-controlled trial
PubMed ID: 36016763
300 mg caffeine significantly improved vigilance RT in tactical personnel (robust, well‑controlled trial).
- Effects of modafinil and caffeine on night-time vigilance of air force crewmembers: A randomized controlled trial
PubMed ID: 36515156
Caffeine improved PVT reaction time and reduced lapses after prolonged wakefulness — strong vigilance effect.
- Effect of caffeine on resting-state alpha activity across the human menstrual cycle
PubMed ID: 35904580
EEG showed decreased lower‑alpha power after 200 mg caffeine—objective index of increased arousal/alertness.
- Bright light alone or combined with caffeine improves sleepiness in chronically sleep-restricted young drivers
PubMed ID: 35398627
Combined bright light + caffeine reduced subjective sleepiness and improved lane-keeping and EEG indices (strong alerting effects).
- The effect of mouth rinsing with different concentrations of caffeine solutions on reaction time
PubMed ID: 35193478
Immediate, large RT improvements with mouth-rinsed caffeine indicate rapid wakefulness/arousal effects.
- Acute Effects of Coffee Consumption on Health among Ambulatory Adults
PubMed ID: 36947466
Coffee days were associated with substantially less sleep and higher activity, compatible with faster daytime wakefulness.
- Daily Caffeine Intake and the Effect of Caffeine on Pilots' Performance After Extended Wakefulness
PubMed ID: 37726901
300 mg improved overnight attention/vigilance and reduced performance decline in extended‑wake pilots — strong, operationally relevant effect.
- Relationship between Habitual Caffeine Consumption, Attentional Performance, and Individual Alpha Frequency during Total Sleep Deprivation
PubMed ID: 36981883
Acute caffeine improved psychomotor vigilance RT and decreased theta/alpha EEG power associated with sleepiness.
- Acute Cognitive Performance and Mood Effects of Coffeeberry Extract: A Randomized, Double Blind, Placebo-Controlled Crossover Study in Healthy Humans
PubMed ID: 37299382
75 mg caffeine positive control produced consistent alerting effects across tasks.
- Effects of Dietary Supplementation of a Microalgae Extract Containing Fucoxanthin Combined with Guarana on Cognitive Function and Gaming Performance
PubMed ID: 37111136
Faster reaction times and fewer perseverative errors suggest improved vigilance in gamers.
- Stress response to virtual reality based active shooter training: Impact of caffeine consumption
PubMed ID: 38142605
Caffeine increased salivary α-amylase after stress, consistent with heightened sympathetic arousal/alertness.
- Repeated caffeine intake suppresses cerebral grey matter responses to chronic sleep restriction in an A(1) adenosine receptor-dependent manner: a double-blind randomized controlled study with PET-MRI
PubMed ID: 38830861
Repeated caffeine during partial sleep restriction altered brain MRI changes linked to sleep loss and linked to adenosine A1R — mechanistic support for alerting effects.
- The effects of caffeine mouth rinsing on selective attention as a function of different caffeine concentrations and perceived taste intensity in recreationally active males at rest: a randomized placebo-controlled cross-over trial
PubMed ID: 39495309
Mouth‑rinse improved Stroop speed and reduced errors (better sustained/selective vigilance over short tasks).
- Effects of the active botanical blend "WKUP GT" on attention and cognitive functions after lunch in healthy volunteers
PubMed ID: 38367243
Caffeinated beverage improved rapid visual information processing and some multitasking measures post‑lunch — vigilance improvements.
- Examining the effects of caffeine during an auditory attention task
PubMed ID: 39098270
200 mg gum increased alertness and arousal/positive affect vs placebo.
- Acute effects of 150 mg caffeine on subjective, physiological, and behavioral components of anxiety in panic disorder and healthy controls - A randomized placebo-controlled crossover trial
PubMed ID: 40577029
150 mg caffeine produced measurable increases in skin conductance (physiological arousal), consistent with increased alertness.
- High-dose L-theanine-caffeine combination improves neurobehavioural and neurophysiological measures of selective attention in acutely sleep-deprived young adults: a double-blind, placebo-controlled crossover study
PubMed ID: 40789769
L‑theanine+caffeine improved detection accuracy and ERP markers in sleep‑deprived adults indicating enhanced vigilance.
- Transcranial direct current stimulation combined with caffeine promotes executive function in healthy females
PubMed ID: 40888092
tDCS+CAF improved working memory and Stroop incongruent accuracy, consistent with transient vigilance/monitoring improvements.
- A Randomized Study to Examine the Ability of a Caffeine-Based Energy Drink to Impact Energy Expenditure, Fat Oxidation, and Cognitive Performance
PubMed ID: 41374082
Dynavision correct‑hit improvements and subjective focus/energy indicate improved sustained vigilance.},{
- Acute Cardiovascular Effects of Turkish Coffee Assessed by VO(2) Test: A Randomized Crossover Trial
PubMed ID: 40077691
Turkish coffee increased subjective energy/attention within 60–120 min, consistent with faster wakefulness.
- Impact of acute caffeine intake on local tolerance to cold before and after total sleep deprivation
PubMed ID: 40150834
Caffeine improved peripheral thermoregulation and rewarming after sleep loss, which can aid wakefulness recovery.},{
- Efficacy of caffeine supplementation on fatigue in patients with multiple sclerosis: A randomized double-blind placebo-controlled trial
PubMed ID: 41406935
12 weeks of 100 mg/day reduced fatigue and raised vitality in MS patients (sustained alertness/energy).
- Effects of two doses of glucose and a caffeine-glucose combination on cognitive performance and mood during multi-tasking
PubMed ID: 25196040
Improvements in multitasking and sustained processing speed with caffeine+glucose imply better vigilance across tasks.
- A comparison of the effects of transcranial direct current stimulation and caffeine on vigilance and cognitive performance during extended wakefulness
PubMed ID: 25047826
Caffeine improved reaction times and cognitive measures during prolonged wakefulness, supporting faster restoration of wakeful performance.
- An evaluation of the cognitive and mood effects of an energy shot over a 6h period in volunteers: a randomized, double-blind, placebo controlled, cross-over study
PubMed ID: 23587521
Energy shot increased self-rated alertness and improved multiple composite cognitive measures up to 6 h (multi-ingredient).
- Caffeine can decrease subjective energy depending on the vehicle with which it is consumed and when it is measured
PubMed ID: 23455596
Caffeine improved vigilance and working memory in a large trial—supports sustained task vigilance.
- Psychopharmacology of theobromine in healthy volunteers
PubMed ID: 23420115
200 mg caffeine produced classic stimulant subjective effects (increased 'feel' and BP), consistent with heightened alertness.
- A moderate dose of caffeine ingestion does not change energy expenditure but decreases sleep time in physically active males: a double-blind randomized controlled trial
PubMed ID: 23368828
Moderate twice-daily caffeine reduced total sleep time and maintained wakefulness across the study period.
- Caffeine effects on resting-state electrodermal levels in AD/HD suggest an anomalous arousal mechanism
PubMed ID: 22266163
Caffeine raised skin conductance (physiologic arousal) in children, consistent with increased alertness/arousal.
- Acute effects of caffeine on attention: a comparison of non-consumers and withdrawn consumers
PubMed ID: 22992376
2 mg/kg caffeine produced greater target detection and fewer lapses, directly improving vigilance.
- Differential cognitive effects of energy drink ingredients: caffeine, taurine, and glucose
PubMed ID: 22819803
Improvements in executive control and reaction times after abstinence indicate better task vigilance.
- In-car nocturnal blue light exposure improves motorway driving: a randomized controlled trial
PubMed ID: 23094031
Caffeinated coffee (2×200 mg) produced a large, clinically meaningful reduction in inappropriate line crossings during prolonged night driving—strong vigilance evidence.
- Polymorphisms of ADORA2A modulate psychomotor vigilance and the effects of caffeine on neurobehavioural performance and sleep EEG after sleep deprivation
PubMed ID: 21950736
Genotype-moderated preservation of alertness after sleep deprivation demonstrates strong caffeine effects on vigilance in responsive individuals.
- Caffeine, extraversion and working memory
PubMed ID: 23015541
65 mg improved simple reaction time and encoding speed — signs of increased alertness.
- Faster but not smarter: effects of caffeine and caffeine withdrawal on alertness and performance
PubMed ID: 23108937
Large study showing robust reversal of withdrawal sleepiness and improved alertness; habitual-use effects described.
- Caffeine for treatment of Parkinson disease: a randomized controlled trial
PubMed ID: 22855866
Short-term caffeine modestly improved objective motor signs and gave borderline improvement in sleepiness in Parkinson's patients (sleepiness proxy).
- Expectation of having consumed caffeine can improve performance and mood
PubMed ID: 21824504
Both expectation and actual caffeine improved attention and vigour—strong evidence for increased alertness.
- Acute caffeine consumption enhances the executive control of visual attention in habitual consumers
PubMed ID: 20832925
400 mg acutely improved vigilance and executive control in habitual users; clear vigilance benefit at high dose.
- Caffeine and stress alter salivary alpha-amylase activity in young men
PubMed ID: 20589924
Dose‑dependent increases in salivary alpha‑amylase after caffeine + stress indicate increased physiological arousal/alertness.
- Interaction between drug and placebo effects: a cross-over balanced placebo design trial
PubMed ID: 21092089
300 mg caffeine robustly increased self‑reported energy and reduced sleepiness in a large balanced‑placebo crossover.
- Acute effects of a glucose energy drink on behavioral control
PubMed ID: 21186930
Energy drink (glucose+caffeine) increased feelings of stimulation and reduced mental fatigue, consistent with increased alertness.
- Effects of caffeine and glucose, alone and combined, on cognitive performance
PubMed ID: 20521321
Caffeine+glucose improved sustained attention measures, consistent with better vigilance (combo effect).
- The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness
PubMed ID: 21040626
Combination of L-theanine + caffeine increased subjective alertness along with objective attention benefits.
- Sustaining executive functions during sleep deprivation: A comparison of caffeine, dextroamphetamine, and modafinil
PubMed ID: 19238808
High-dose caffeine improved some cognitive measures after extended wakefulness, consistent with selective vigilance benefits.
- Effects of caffeine in chewing gum on mood and attention
PubMed ID: 19330801
Caffeinated gum improved sustained attention (vigilance) in a relatively large behavioral sample.
- Caffeine effects on resting-state arousal in children
PubMed ID: 19486913
EEG and skin conductance showed increased physiological arousal after 80 mg caffeine (direct alertness biomarker support).
- Early effects of caffeinated and decaffeinated coffee on subjective state and gender differences
PubMed ID: 18675877
100 mg produced rapid decreases in somnolence and increases in activation within 10–30 minutes.
- Effects of dextroamphetamine, caffeine and modafinil on psychomotor vigilance test performance after 44 h of continuous wakefulness
PubMed ID: 18522689
600 mg restored psychomotor vigilance performance and reduced lapses after 44 h wakefulness — strong evidence for vigilance restoration.
- Enhanced mood and psychomotor performance by a caffeine-containing energy capsule in fatigued individuals
PubMed ID: 18266548
200 mg improved subjective vigor and shortened reaction times after sleep loss — robust alerting effect.
- Comparing the benefits of caffeine, naps and placebo on verbal, motor and perceptual memory
PubMed ID: 18554731
200 mg increased alertness in the afternoon compared with napping/placebo despite memory tradeoffs.
- Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together
PubMed ID: 17891480
250 mg caffeine robustly increased self-rated alertness (and physiological stimulation).
- The effects of caffeine, dextroamphetamine, and modafinil on humor appreciation during sleep deprivation
PubMed ID: 16796223
High-dose caffeine reduced sleepiness and improved response speed during prolonged sleep deprivation (vigilance proxy).
- Laboratory and field studies of naps and caffeine as practical countermeasures for sleep-wake problems associated with night work
PubMed ID: 16453980
Caffeine (with naps) improved psychomotor vigilance (PVT) and maintenance of wakefulness for night-shift workers.
- Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine users
PubMed ID: 16541243
Clear improvement in vigilance hits and faster reaction times after acute caffeine dosing.
- Multiple caffeine doses maintain vigilance during early morning operations
PubMed ID: 16313140
Strong randomized data: 200 mg every 2 h prevented vigilance lapses overnight, directly demonstrating preserved task vigilance.
- Caffeine deprivation state modulates coffee consumption but not attentional bias for caffeine-related stimuli
PubMed ID: 16170233
Deprivation-induced drowsiness suggests re-dosing caffeine restores wakefulness quickly.
- Cognitive and mood improvements of caffeine in habitual consumers and habitual non-consumers of caffeine
PubMed ID: 15678363
Digit vigilance RT and other vigilance measures improved with caffeine.
- Multiple dose pharmacokinetics of caffeine administered in chewing gum to normal healthy volunteers
PubMed ID: 16158445
Dose-proportional, rapid absorption from gum supports rapid onset of effects.
- Effects of repeated doses of caffeine on mood and performance of alert and fatigued volunteers
PubMed ID: 16272184
Dose-related increases in arousal and performance, especially when fatigued.
- The fixed combination of valerian and hops (Ze91019) acts via a central adenosine mechanism
PubMed ID: 15254851
EEG study shows 200 mg caffeine causes measurable brain arousal that valerian can attenuate (direct arousal effect).
- Methylxanthines are the psycho-pharmacologically active constituents of chocolate
PubMed ID: 15549276
Cocoa methylxanthines produced small increases in energetic arousal and cognitive performance.
- A glucose-caffeine 'energy drink' ameliorates subjective and performance deficits during prolonged cognitive demand
PubMed ID: 15183925
Caffeine+glucose improved sustained attention (RVIP) and reduced mental fatigue — direct evidence for improved vigilance.
- Caffeine effects on marksmanship during high-stress military training with 72 hour sleep deprivation
PubMed ID: 12688447
Caffeine (200–300 mg) improved aiming speed under 72+ h sleep deprivation without accuracy loss, indicating maintained vigilance in a demanding task.
- A comparison of tyrosine against placebo, phentermine, caffeine, and D-amphetamine during sleep deprivation
PubMed ID: 12887139
During 40.5 h sleep deprivation caffeine reduced sleep drive vs placebo, indicating preserved alertness under extended wakefulness.
- The rate of absorption and relative bioavailability of caffeine administered in chewing gum versus capsules to normal healthy volunteers
PubMed ID: 11839447
Chewing gum produced faster Tmax than capsules, supporting a quicker wakefulness onset.
- Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Sea-Air-Land
PubMed ID: 12424548
Substantial, dose‑dependent improvements in visual vigilance in sleep‑deprived trainees — strongest evidence for vigilance benefit.
- Effects of caffeine on performance and mood depend on the level of caffeine abstinence
PubMed ID: 12424547
Caffeine improved attention and alertness in deprived moderate users (behavioral data).
- Maintaining alertness and performance during sleep deprivation: modafinil versus caffeine
PubMed ID: 11862356
High-dose caffeine (600 mg) effectively maintained alertness and performance during extended wakefulness (comparable to modafinil).
- The effects of red bull energy drink on human performance and mood
PubMed ID: 11665810
Multicomponent energy drink increased subjective alertness vs control (caffeine likely contributed though not isolated).
- A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality
PubMed ID: 10823400
Day‑long caffeinated tea/coffee prevented the daytime decline in CFF and supported some reaction‑time measures (alertness index).
Focus & concentration (98)
- Effects of repeated doses of caffeine on mood and performance of alert and fatigued volunteers
PubMed ID: 16272184
Dose-related improvements in mood and task performance, particularly under fatigue.
- The fixed combination of valerian and hops (Ze91019) acts via a central adenosine mechanism
PubMed ID: 15254851
Valerian blocked EEG arousal caused by 200 mg caffeine — implies caffeine alone produces central arousal supporting focus.
- Methylxanthines are the psycho-pharmacologically active constituents of chocolate
PubMed ID: 15549276
Chocolate doses (caffeine+theobromine) produced modest improvements in energy and cognitive performance vs controls.
- A glucose-caffeine 'energy drink' ameliorates subjective and performance deficits during prolonged cognitive demand
PubMed ID: 15183925
Caffeine+glucose improved sustained attention/accuracy (RVIP) in two crossover studies — direct evidence.
- Caffeine effects on marksmanship during high-stress military training with 72 hour sleep deprivation
PubMed ID: 12688447
Under sleep deprivation caffeine improved aiming speed and preserved performance — applied evidence of faster task execution.
- Effects of caffeine on performance and mood depend on the level of caffeine abstinence
PubMed ID: 12424547
Caffeine decreased reaction time and improved accuracy in sustained attention tasks in deprived moderate users.
- Maintaining alertness and performance during sleep deprivation: modafinil versus caffeine
PubMed ID: 11862356
600 mg caffeine preserved cognitive/psychomotor performance and alertness during sleep deprivation, supporting sustained concentration.
- The effects of red bull energy drink on human performance and mood
PubMed ID: 11665810
Energy-drink increased choice reaction performance and subjective alertness vs control (caffeine likely contributory but not isolated).
- A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality
PubMed ID: 10823400
Maintained CFF and some RT improvements across the day suggest better on‑task concentration.
- Breakfast cereal and caffeinated coffee: effects on working memory, attention, mood, and cardiovascular function
PubMed ID: 10463623
Caffeinated coffee improved learning/encoding, consistent with better short-term attentional processing.
- Mood and psychomotor performance effects of the first, but not of subsequent, cup-of-coffee equivalent doses of caffeine consumed after overnight caffeine abstinence
PubMed ID: 9862086
Simple reaction time improvements after a coffee-equivalent dose support modest gains in mental speed.
- Caffeine deprivation affects vigilance performance and mood
PubMed ID: 9811379
Morning caffeine deprivation reduced sustained attention—evidence caffeine supports short-term attention.
- Caffeine enhances initial but not extended learning of a proprioceptive-based discrimination task in nonsmoking moderate users
PubMed ID: 8774028
Early-session response speed improvement on a fine motor task indicates faster mental/response processing initially.
- The use of caffeine versus prophylactic naps in sustained performance
PubMed ID: 7792499
Caffeine dosing regimens improved vigilance/attention measures during sleep loss in a large trial.
- An auditory attention task: a note on the processing of verbal information
PubMed ID: 8022682
Caffeine restored auditory attention after sleep deprivation—supporting short-term attention maintenance.
- Influence of caffeine on information processing stages in well rested and fatigued subjects
PubMed ID: 7862853
Caffeine shortened reaction times and increased cortical arousal/perceptual sensitivity, consistent with better focus, esp. when fatigued.
- Does caffeine intake enhance absolute levels of cognitive performance?
PubMed ID: 7870897
Large observational data linking higher habitual caffeine intake to better reaction times and reasoning—supports faster mental processing.
- Caffeine reversal of sleep deprivation effects on alertness and mood
PubMed ID: 7871042
Large RCT: high-dose caffeine after sleep deprivation markedly improved alertness and mood, consistent with improved focus.
- Effects of breakfast and caffeine on performance and mood in the late morning and after lunch
PubMed ID: 1299795
Direct demonstration of improved sustained attention and related cognitive tasks after caffeine (strongest cognitive evidence in the set).
- Daytime sleepiness, performance, mood, nocturnal sleep: the effect of benzodiazepine and caffeine on their relationship
PubMed ID: 2184488
Caffeine reduced sleepiness-related performance declines, benefiting short-term attention.
- Cognitive and Mood Effects of a Nutrient Enriched Breakfast Bar in Healthy Adults: A Randomised, Double-Blind, Placebo-Controlled, Parallel Groups Study
PubMed ID: 29215606
RVIP accuracy and speed improved acutely with the caffeinated nutrient bar — direct evidence for short‑term attention.
- Separate and joint effects of alcohol and caffeine on conflict monitoring and adaptation
PubMed ID: 26815360
Caffeine sped behavioral responses and reduced some RT compatibility effects, demonstrating faster cognitive responses (mental speed).
- Caffeine expectancies influence the subjective and behavioral effects of caffeine
PubMed ID: 19760283
280 mg caffeine improved sustained attention and psychomotor speed in a randomized study (objective improvement in focus).
- Interactions between alcohol and caffeine in relation to psychomotor speed and accuracy
PubMed ID: 12404692
Caffeine sped DSST psychomotor speed and antagonized alcohol-induced slowing on several measures.
- Effect of three caffeine doses on plasma catecholamines and alertness during prolonged wakefulness
PubMed ID: 11151742
Dose-related reaction-time improvements and faster sleep-latency indicate faster processing speed.
- Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Sea-Air-Land
PubMed ID: 12424548
Large, well‑powered improvements in vigilance and repeated acquisition tasks under sleep deprivation.
- Efficacy of caffeine supplementation on fatigue in patients with multiple sclerosis: A randomized double-blind placebo-controlled trial
PubMed ID: 41406935
Daily 100 mg reduced fatigue and improved vitality/QoL in MS, which commonly improves sustained focus.
- Acute Cardiovascular Effects of Turkish Coffee Assessed by VO(2) Test: A Randomized Crossover Trial
PubMed ID: 40077691
Single dose Turkish coffee increased subjective energy/attention acutely.
- A Randomized Study to Examine the Ability of a Caffeine-Based Energy Drink to Impact Energy Expenditure, Fat Oxidation, and Cognitive Performance
PubMed ID: 41374082
Energy drink raised perceived focus and improved some Dynavision cognitive hits (subjective+objective focus signals).
- Comparing Effects of Caffeine and Total Motion Release Technique on Cognitive, Neuromuscular, and Anaerobic Function in Semi-Professional Male Sprinters: A Randomized Controlled Trial
PubMed ID: 40221884
Caffeine reduced Flanker reaction times and improved cognitive accuracy in sprinters (better focused responding).
- Transcranial direct current stimulation combined with caffeine promotes executive function in healthy females
PubMed ID: 40888092
Caffeine (alone and with tDCS) improved 3‑back working memory accuracy and Stroop incongruent accuracy — better short‑term attention/working memory.
- High-dose L-theanine-caffeine combination improves neurobehavioural and neurophysiological measures of selective attention in acutely sleep-deprived young adults: a double-blind, placebo-controlled crossover study
PubMed ID: 40789769
Marked improvements in target detection accuracy and discrimination (A′) with L‑theanine+caffeine in sleep‑deprived adults.
- Examining the effects of caffeine during an auditory attention task
PubMed ID: 39098270
Caffeinated gum (200 mg) improved sustained attention and reduced lapses/mind‑wandering.
- Effects of the active botanical blend "WKUP GT" on attention and cognitive functions after lunch in healthy volunteers
PubMed ID: 38367243
Caffeinated beverage improved rapid visual information processing and some post‑lunch attentional measures.
- The effects of caffeine mouth rinsing on selective attention as a function of different caffeine concentrations and perceived taste intensity in recreationally active males at rest: a randomized placebo-controlled cross-over trial
PubMed ID: 39495309
Strong acute effects on Stroop task completion time and error reduction after caffeine mouth‑rinse (direct short‑term attention measure).
- Concurrent consumption of cocoa flavanols and caffeine does not acutely modulate working memory and attention
PubMed ID: 39607519
200 mg produced ~25 ms faster temporal‑attention RT and modest gains in visual search RT (short‑term attention speed).
- Effects of Dietary Supplementation of a Microalgae Extract Containing Fucoxanthin Combined with Guarana on Cognitive Function and Gaming Performance
PubMed ID: 37111136
Notable acute and 30-day reductions in reaction times indicate faster mental processing.
- Acute Cognitive Performance and Mood Effects of Coffeeberry Extract: A Randomized, Double Blind, Placebo-Controlled Crossover Study in Healthy Humans
PubMed ID: 37299382
75 mg positive‑control reliably increased alertness and task performance including short‑term attention measures.
- Relationship between Habitual Caffeine Consumption, Attentional Performance, and Individual Alpha Frequency during Total Sleep Deprivation
PubMed ID: 36981883
Acute caffeine improved RT/vigilance, reflecting improved mental speed.
- Daily Caffeine Intake and the Effect of Caffeine on Pilots' Performance After Extended Wakefulness
PubMed ID: 37726901
300 mg preserved psychomotor vigilance and attention overnight compared with placebo.
- The effect of mouth rinsing with different concentrations of caffeine solutions on reaction time
PubMed ID: 35193478
Dose-dependent, large improvements in RT are consistent with enhanced short-term attentional performance.
- Bright light alone or combined with caffeine improves sleepiness in chronically sleep-restricted young drivers
PubMed ID: 35398627
Caffeine with bright light improved driving vigilance and EEG markers tied to sustained attention.
- Effect of caffeine on resting-state alpha activity across the human menstrual cycle
PubMed ID: 35904580
EEG arousal effects indicate neural substrate for improved concentration after 200 mg.
- Effects of modafinil and caffeine on night-time vigilance of air force crewmembers: A randomized controlled trial
PubMed ID: 36515156
Vigilance improvements after long wakefulness indicate improved short‑term attention to tasks.
- Caffeine and attentional control: improved and impaired performance in healthy older adults and Parkinson's disease according to task demands
PubMed ID: 35006304
100 mg after 1‑week abstinence improved response selection and some attention metrics in older adults/PD.
- Cognitive enhancement: Effects of methylphenidate, modafinil, and caffeine on latent memory and resting state functional connectivity in healthy adults
PubMed ID: 35670369
Robust improvements in immediate and 24‑h recall indicate strong short‑term attention/memory benefits.
- Caffeine selectively mitigates cognitive deficits caused by sleep deprivation
PubMed ID: 34014758
Large RCT: caffeine reduced PVT lapses and restored vigilant attention after sleep deprivation (robust short-term attention benefit).
- Matcha consumption maintains attentional function following a mild acute psychological stress without affecting a feeling of fatigue: A randomized placebo-controlled study in young adults
PubMed ID: 33744591
Two-week matcha maintained attentional reaction time post-stress (multi-constituent product including caffeine).
- Genetic Determinants of Neurobehavioral Responses to Caffeine Administration during Sleep Deprivation: A Randomized, Cross Over Study (NCT03859882)
PubMed ID: 33920292
Caffeine reduced PVT lapses and EEG theta during prolonged wakefulness—improves short-term sustained attention.
- Effects of Daily Matcha and Caffeine Intake on Mild Acute Psychological Stress-Related Cognitive Function in Middle-Aged and Older Adults: A Randomized Placebo-Controlled Study
PubMed ID: 34067795
Acute caffeine shortened reaction times and supported attention tasks — direct support for improved short‑term attention.
- Expectation for stimulant type modifies caffeine's effects on mood and cognition among college students
PubMed ID: 33734725
200 mg increased subjective stimulation and produced modest working‑memory gains, consistent with improved focus.
- Percolating ideas: The effects of caffeine on creative thinking and problem solving
PubMed ID: 32086187
200 mg caffeine improved convergent problem‑solving (cognitive focus on a task) in RCT.
- Cognitive enhancement effects of stimulants: a randomized controlled trial testing methylphenidate, modafinil, and caffeine
PubMed ID: 33201262
200 mg caffeine modestly sped sustained-attention RT (PVT) in healthy adults.
- Blood dopamine level enhanced by caffeine in men after treadmill running
PubMed ID: 31793465
3 mg/kg before running raised plasma dopamine and β-endorphin post-exercise—neurochemical changes consistent with improved central focus/reduced fatigue.
- Influence of genetic polymorphisms and habitual caffeine intake on the changes in blood pressure, pulse rate, and calculation speed after caffeine intake: A prospective, double blind, randomized trial in healthy volunteers
PubMed ID: 30773300
Caffeine increased calculation speed in a large randomized trial — strong evidence for faster mental processing.
- Using coffee to compensate for poor sleep: Impact on vigilance and implications for workplace performance
PubMed ID: 29866304
100 mg coffee improved RT repeatedly, consistent with increased mental speed.
- The Acute Effects of Caffeinated Black Coffee on Cognition and Mood in Healthy Young and Older Adults
PubMed ID: 30274327
100 mg brewed coffee improved attention accuracy and reaction time vs placebo/decaf.
- Effect of single caffeine intake on neuropsychological functions in healthy volunteers: A double-blind placebo-controlled study
PubMed ID: 30379815
Single 200 mg improved some attention/executive scores (SAT correct responses) in 100 subjects.
- Acute effects of caffeine on threat-selective attention: moderation by anxiety and EEG theta/beta ratio
PubMed ID: 29792908
200 mg altered threat-related attention depending on baseline brain marker/anxiety (modulatory effect).
- Low dose of caffeine enhances the efficacy of antidepressants in major depressive disorder and the underlying neural substrates
PubMed ID: 28054436
Chronic low‑dose (60 mg/day) caffeine adjunct improved cognition in depressed inpatients.
- Investigating the effects of caffeine on executive functions using traditional Stroop and a new ecologically-valid virtual reality task, the Jansari assessment of Executive Functions (JEF(©))
PubMed ID: 27215836
Caffeinated coffee improved executive function metrics (planning, prospective memory) and reaction time—direct evidence for improved concentration.
- Effects of a single, oral 60 mg caffeine dose on attention in healthy adult subjects
PubMed ID: 27649778
Significant improvement on sustained-attention tasks (Mackworth Clock, RVIP) after single 60 mg dose.
- Acute personalized habitual caffeine doses improve attention and have selective effects when considering the fractionation of executive functions
PubMed ID: 26621326
Individualized morning caffeine dose reduced subjective fatigue and improved simple/sustained attention and one executive domain (updating).
- Subjective and objective effects of coffee consumption - caffeine or expectations?
PubMed ID: 25481367
Subjective arousal and expectancy effects support potential concentration gains in some contexts.
- The effects of caffeine on option generation and subsequent choice
PubMed ID: 24682504
300 mg caffeine reduced time to generate the first option (faster cognitive initiation) — direct evidence of faster mental response.
- Improvements in concentration, working memory and sustained attention following consumption of a natural citicoline-caffeine beverage
PubMed ID: 25046515
Improved continuous performance reaction times after citicoline–caffeine beverage imply better short‑term attention (multi‑ingredient).
- Acute caffeine administration effect on brain activation patterns in mild cognitive impairment
PubMed ID: 24577471
In MCI, caffeine broadened working‑memory related activation patterns (neural proxy for compensatory concentration mechanisms).
- Effects of two doses of glucose and a caffeine-glucose combination on cognitive performance and mood during multi-tasking
PubMed ID: 25196040
Caffeine (40 mg) + glucose improved executive attention and multi‑tasking speed in a large RCT, indicating better concentration.
- A comparison of the effects of transcranial direct current stimulation and caffeine on vigilance and cognitive performance during extended wakefulness
PubMed ID: 25047826
Caffeine improved reaction times and some short‑term memory latencies across extended wakefulness.
- An evaluation of the cognitive and mood effects of an energy shot over a 6h period in volunteers: a randomized, double-blind, placebo controlled, cross-over study
PubMed ID: 23587521
Energy shot improved several validated cognitive composites (including attention measures) in partially sleep-deprived participants.
- Caffeine and cognitive decline in elderly women at high vascular risk
PubMed ID: 23422357
Observational data linking habitual caffeine with preserved cognition suggests potential longer-term attention benefits (associative).
- Caffeine can decrease subjective energy depending on the vehicle with which it is consumed and when it is measured
PubMed ID: 23455596
Caffeine improved reaction time, working memory and vigilance—supporting improvements in mental speed.
- Psychopharmacology of theobromine in healthy volunteers
PubMed ID: 23420115
200 mg caffeine produced clear stimulant subjective effects (feel/high/want) consistent with improved attentional engagement.
- A moderate dose of caffeine ingestion does not change energy expenditure but decreases sleep time in physically active males: a double-blind randomized controlled trial
PubMed ID: 23368828
Moderate twice-daily caffeine preserved wakefulness but reduced sleep; shows stimulatory effects that can support daytime focus.
- Acute effects of caffeine on attention: a comparison of non-consumers and withdrawn consumers
PubMed ID: 22992376
2 mg/kg produced faster encoding and improved simple reaction times, indicating enhanced mental processing speed.
- Differential cognitive effects of energy drink ingredients: caffeine, taurine, and glucose
PubMed ID: 22819803
Improved executive control and working memory after 200 mg — supports enhanced concentration.
- In-car nocturnal blue light exposure improves motorway driving: a randomized controlled trial
PubMed ID: 23094031
Night-driving improvements imply more stable concentration during prolonged attention-demanding tasks.
- Polymorphisms of ADORA2A modulate psychomotor vigilance and the effects of caffeine on neurobehavioural performance and sleep EEG after sleep deprivation
PubMed ID: 21950736
Caffeine moderated PVT performance across sleep deprivation in genotype-dependent ways, supporting short-term attentional benefits in responders.
- Caffeine, extraversion and working memory
PubMed ID: 23015541
65 mg sped simple reaction time and encoding speed and aided certain memory tasks (mental speed gains).
- Faster but not smarter: effects of caffeine and caffeine withdrawal on alertness and performance
PubMed ID: 23108937
Large-sample data: caffeine improved alertness and motor performance; benefits moderated by habitual use.
- Expectation of having consumed caffeine can improve performance and mood
PubMed ID: 21824504
Direct improvement in attention/psychomotor speed with caffeine and expectancy — strong support for short-term attention gains.
- Caffeine enhances working memory for extraverts
PubMed ID: 20816912
200 mg caffeine improved working memory in extraverts (cognitive subgroup effect).
- Acute caffeine consumption enhances the executive control of visual attention in habitual consumers
PubMed ID: 20832925
400 mg caffeine improved vigilance and executive control — strong evidence for enhanced concentration at high dose.
- Acute effects of a glucose energy drink on behavioral control
PubMed ID: 21186930
Energy drink sped reaction times on cognitive tasks, indicating quicker mental responses (product contains caffeine).
- Effects of caffeine and glucose, alone and combined, on cognitive performance
PubMed ID: 20521321
Caffeine+glucose enhanced sustained attention and verbal memory; caffeine alone improved simple RT (short-term attention result).
- The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness
PubMed ID: 21040626
L-theanine plus caffeine produced large improvements in task-switching accuracy and subjective alertness, supporting concentration gains.
- Effects of caffeine in chewing gum on mood and attention
PubMed ID: 19330801
40 mg caffeinated gum improved sustained attention and sped encoding of new information in a study of 118 subjects.
- Caffeine effects on resting-state arousal in children
PubMed ID: 19486913
EEG changes and increased SCL after 80 mg caffeine are consistent with improved readiness to concentrate.
- Early effects of caffeinated and decaffeinated coffee on subjective state and gender differences
PubMed ID: 18675877
100 mg reduced sleepiness and boosted activation over 10–30 min, supporting brief attention improvements.
- Effects of dextroamphetamine, caffeine and modafinil on psychomotor vigilance test performance after 44 h of continuous wakefulness
PubMed ID: 18522689
600 mg reliably restored psychomotor vigilance (PVT) and reduced lapses after 44 h wakefulness — strong short‑term attention benefit.
- Enhanced mood and psychomotor performance by a caffeine-containing energy capsule in fatigued individuals
PubMed ID: 18266548
200 mg shortened reaction times in sleep‑deprived subjects — direct improvement in simple mental speed measures.
- Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together
PubMed ID: 17891480
Caffeine increased subjective alertness and attentional readiness, supporting concentration improvements.
- The effects of caffeine, dextroamphetamine, and modafinil on humor appreciation during sleep deprivation
PubMed ID: 16796223
Improved psychomotor response speed during extended wakefulness with high-dose caffeine.
- Laboratory and field studies of naps and caffeine as practical countermeasures for sleep-wake problems associated with night work
PubMed ID: 16453980
Caffeine improved psychomotor vigilance and maintenance of attention for shift-workers.
- Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine users
PubMed ID: 16541243
Increased vigilance hits and faster reaction times indicate improved short-term attention.
- Multiple caffeine doses maintain vigilance during early morning operations
PubMed ID: 16313140
Strong prevention of psychomotor vigilance lapses overnight demonstrates preserved short‑term attention.
- The effects of combined caffeine and glucose drinks on attention in the human brain
PubMed ID: 16117181
Caffeine+glucose improved speed/accuracy on an attention-demanding task (combination product).
- Cognitive and mood improvements of caffeine in habitual consumers and habitual non-consumers of caffeine
PubMed ID: 15678363
Improved digit vigilance RT and working-memory RT indicate better short-term attention.
Productivity (73)
- Caffeine expectancies influence the subjective and behavioral effects of caffeine
PubMed ID: 19760283
Vigilance reaction time and psychomotor speed were objectively improved with 280 mg caffeine.
- Interactions between alcohol and caffeine in relation to psychomotor speed and accuracy
PubMed ID: 12404692
Antagonized alcohol-related slowing and improved some reaction-time metrics and DSST speed.
- Effect of three caffeine doses on plasma catecholamines and alertness during prolonged wakefulness
PubMed ID: 11151742
Dose‑related improvements in choice reaction time and sleep-latency measures.
- Does caffeine intake enhance absolute levels of cognitive performance?
PubMed ID: 7870897
Large study found higher habitual caffeine linked to better simple and choice reaction times (strong observational support).
- Caffeine reversal of sleep deprivation effects on alertness and mood
PubMed ID: 7871042
Restoration of alertness after sleep deprivation likely improves reaction times when sleep‑deprived.
- Effects of breakfast and caffeine on performance and mood in the late morning and after lunch
PubMed ID: 1299795
Improvements in attention and reasoning can translate to better task performance/productivity.
- Daytime sleepiness, performance, mood, nocturnal sleep: the effect of benzodiazepine and caffeine on their relationship
PubMed ID: 2184488
Reduced subjective sleepiness–performance link suggests potential productivity gains.
- Separate and joint effects of alcohol and caffeine on conflict monitoring and adaptation
PubMed ID: 26815360
Caffeine sped behavioral responses and altered neural conflict markers; RT compatibility effects reduced (robust evidence for faster responding).
- Influence of caffeine on information processing stages in well rested and fatigued subjects
PubMed ID: 7862853
Caffeine shortened reaction times in a sizeable ERP/behavioral study, especially in fatigued subjects.
- Conditioned flavour preferences reinforced by caffeine consumed after lunch
PubMed ID: 8804673
Habitual post-lunch caffeine relieved the post-lunch dip and reinforced beverage preference — behavioral evidence consistent with improved afternoon productivity.
- Mood and psychomotor performance effects of the first, but not of subsequent, cup-of-coffee equivalent doses of caffeine consumed after overnight caffeine abstinence
PubMed ID: 9862086
Simple reaction time improved after a coffee-equivalent caffeine dose following overnight abstinence.
- Breakfast cereal and caffeinated coffee: effects on working memory, attention, mood, and cardiovascular function
PubMed ID: 10463623
Reduced fatigue and improved encoding with caffeinated coffee may translate to modest productivity improvements.
- Influence of caffeine on the frequency and perception of hypoglycemia in free-living patients with type 1 diabetes
PubMed ID: 10857934
Low-dose caffeine in type 1 diabetics produced a slight improvement in a reaction-time test.
- A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality
PubMed ID: 10823400
Acute improvements in certain reaction‑time measures were observed with day‑long caffeinated drinks.
- Maintaining alertness and performance during sleep deprivation: modafinil versus caffeine
PubMed ID: 11862356
Maintained cognitive/psychomotor performance during sleep deprivation, which would support sustained productive work.
- Effects of caffeine on performance and mood depend on the level of caffeine abstinence
PubMed ID: 12424547
Breakfast caffeine decreased reaction time in deprived moderate users — behavioral evidence for faster RT.
- Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Sea-Air-Land
PubMed ID: 12424548
Choice reaction time improved dose‑dependently in sleep‑deprived trainees — robust effect.
- Effects of caffeine on performance of low intensity tasks
PubMed ID: 12027348
Caffeine (5 mg/kg) improved a peripheral hand–eye coordination measure, reflecting faster/accurate responses in that task.
- Caffeine effects on marksmanship during high-stress military training with 72 hour sleep deprivation
PubMed ID: 12688447
200–300 mg caffeine improved sighting/aiming speed in sleep-deprived Navy SEAL trainees (faster responses in applied task).
- Effects of repeated doses of caffeine on mood and performance of alert and fatigued volunteers
PubMed ID: 16272184
Improved mood and cognitive performance in fatigued volunteers could translate to greater productivity.
- Cognitive and mood improvements of caffeine in habitual consumers and habitual non-consumers of caffeine
PubMed ID: 15678363
Robust improvements in simple reaction time, digit vigilance RT and working-memory RT after caffeine.
- Multiple caffeine doses maintain vigilance during early morning operations
PubMed ID: 16313140
Prevention of vigilance lapses and maintained psychomotor vigilance is directly tied to faster/consistent reaction times.
- Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine users
PubMed ID: 16541243
Reported faster reaction times and more hits on vigilance tasks after acute caffeine.
- Laboratory and field studies of naps and caffeine as practical countermeasures for sleep-wake problems associated with night work
PubMed ID: 16453980
Caffeine improved psychomotor vigilance performance (PVT) in night-shift contexts.
- The effects of caffeine, dextroamphetamine, and modafinil on humor appreciation during sleep deprivation
PubMed ID: 16796223
High-dose caffeine improved psychomotor response speed during prolonged wakefulness.
- Enhanced mood and psychomotor performance by a caffeine-containing energy capsule in fatigued individuals
PubMed ID: 18266548
200 mg shortened reaction times in sleep‑deprived subjects — direct evidence for faster RT.
- Effects of dextroamphetamine, caffeine and modafinil on psychomotor vigilance test performance after 44 h of continuous wakefulness
PubMed ID: 18522689
600 mg restored PVT speed and reduced lapses after 44 h wakefulness — improved psychomotor speed.
- The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness
PubMed ID: 21040626
Improved attention-switching accuracy and alertness from L-theanine+caffeine plausibly supports short-term productivity gains.
- Effects of caffeine and glucose, alone and combined, on cognitive performance
PubMed ID: 20521321
Caffeine alone improved simple reaction time in fasting young adults in this study.
- Acute effects of a glucose energy drink on behavioral control
PubMed ID: 21186930
Commercial energy drink (glucose+caffeine) acutely sped reaction times on cognitive tasks (composition confound).
- Acute caffeine consumption enhances the executive control of visual attention in habitual consumers
PubMed ID: 20832925
400 mg improved vigilance and executive control on visual tasks — likely linked to faster responses.
- Expectation of having consumed caffeine can improve performance and mood
PubMed ID: 21824504
Caffeine and the expectation of caffeine improved attention/psychomotor speed and vigour—cognitive changes that support productivity.
- Faster but not smarter: effects of caffeine and caffeine withdrawal on alertness and performance
PubMed ID: 23108937
Large-sample evidence for faster simple and choice reaction times with caffeine; habituation matters.
- Caffeine, extraversion and working memory
PubMed ID: 23015541
65 mg improved simple reaction time across participants.
- Polymorphisms of ADORA2A modulate psychomotor vigilance and the effects of caffeine on neurobehavioural performance and sleep EEG after sleep deprivation
PubMed ID: 21950736
Genetic study shows caffeine preserves psychomotor vigilance (PVT) performance after sleep loss — relevant to reaction time.
- In-car nocturnal blue light exposure improves motorway driving: a randomized controlled trial
PubMed ID: 23094031
Improved night-driving performance implies better sustained task performance and fewer performance lapses.
- Differential cognitive effects of energy drink ingredients: caffeine, taurine, and glucose
PubMed ID: 22819803
200 mg reduced simple and choice reaction times in habitual users after abstinence.
- Acute effects of caffeine on attention: a comparison of non-consumers and withdrawn consumers
PubMed ID: 22992376
2 mg/kg produced faster simple reaction times and fewer long responses (strong direct evidence).
- Caffeine can decrease subjective energy depending on the vehicle with which it is consumed and when it is measured
PubMed ID: 23455596
Caffeine improved choice and simple reaction time in a large randomized trial across different vehicles.
- A comparison of the effects of transcranial direct current stimulation and caffeine on vigilance and cognitive performance during extended wakefulness
PubMed ID: 25047826
Caffeine gum improved reaction times during 30 h awake relative to placebo.
- Effects of two doses of glucose and a caffeine-glucose combination on cognitive performance and mood during multi-tasking
PubMed ID: 25196040
Caffeine (40 mg) + glucose (60 g) markedly improved multi‑tasking performance vs placebo in 150 healthy adults (large RCT).
- Post-study caffeine administration enhances memory consolidation in humans
PubMed ID: 24413697
Post‑learning 200 mg caffeine enhanced a form of long‑term memory consolidation (can improve later task performance/productivity for learned material).
- Improvements in concentration, working memory and sustained attention following consumption of a natural citicoline-caffeine beverage
PubMed ID: 25046515
Citicoline–caffeine beverage improved continuous performance reaction times vs placebo (multi‑ingredient but RT benefit observed).
- The effects of caffeine on option generation and subsequent choice
PubMed ID: 24682504
300 mg caffeine sped first‑option generation onset (accelerated initial cognitive response) — related to faster decision initiation.
- Acute personalized habitual caffeine doses improve attention and have selective effects when considering the fractionation of executive functions
PubMed ID: 26621326
Improved attention and reduced fatigue with morning caffeine plausibly support short‑term productivity gains.
- Effects of a single, oral 60 mg caffeine dose on attention in healthy adult subjects
PubMed ID: 27649778
Caffeine reduced reaction times and increased saccadic peak velocity in middle-aged adults.
- Investigating the effects of caffeine on executive functions using traditional Stroop and a new ecologically-valid virtual reality task, the Jansari assessment of Executive Functions (JEF(©))
PubMed ID: 27215836
Caffeinated coffee sped simple reaction time (Stroop RT) vs decaf—direct support for faster reaction time with caffeine.
- Low dose of caffeine enhances the efficacy of antidepressants in major depressive disorder and the underlying neural substrates
PubMed ID: 28054436
Faster symptom improvement and cognitive gains with low‑dose caffeine could translate to better functional productivity.
- Effect of single caffeine intake on neuropsychological functions in healthy volunteers: A double-blind placebo-controlled study
PubMed ID: 30379815
200 mg shortened braking reaction time (~−5.6%) and improved executive RT measures.
- The Acute Effects of Caffeinated Black Coffee on Cognition and Mood in Healthy Young and Older Adults
PubMed ID: 30274327
100 mg coffee sped attention reaction times on vigilance tests vs placebo.
- Using coffee to compensate for poor sleep: Impact on vigilance and implications for workplace performance
PubMed ID: 29866304
100 mg coffee improved RT reliably across repeated measures, though errors increased in poor sleepers.
- Influence of genetic polymorphisms and habitual caffeine intake on the changes in blood pressure, pulse rate, and calculation speed after caffeine intake: A prospective, double blind, randomized trial in healthy volunteers
PubMed ID: 30773300
Increased calculation speed after caffeine supports small improvements in productivity on cognitive tasks.
- Cognitive enhancement effects of stimulants: a randomized controlled trial testing methylphenidate, modafinil, and caffeine
PubMed ID: 33201262
Sustained-attention RT improved (PVT), indicating faster simple reaction times with 200 mg caffeine.
- Percolating ideas: The effects of caffeine on creative thinking and problem solving
PubMed ID: 32086187
Improved convergent problem‑solving ability could translate to task productivity in specific problem‑solving contexts.
- Effects of Daily Matcha and Caffeine Intake on Mild Acute Psychological Stress-Related Cognitive Function in Middle-Aged and Older Adults: A Randomized Placebo-Controlled Study
PubMed ID: 34067795
Acute caffeine shortened reaction times on multiple attention/working‑memory tasks — direct evidence for faster RT.
- Genetic Determinants of Neurobehavioral Responses to Caffeine Administration during Sleep Deprivation: A Randomized, Cross Over Study (NCT03859882)
PubMed ID: 33920292
Caffeine reduced vigilance lapses and improved reaction speed during prolonged wakefulness (PVT evidence).
- Caffeine selectively mitigates cognitive deficits caused by sleep deprivation
PubMed ID: 34014758
Large trial showed caffeine reduced PVT lapses and improved reaction speed after sleep loss.
- Cognitive enhancement: Effects of methylphenidate, modafinil, and caffeine on latent memory and resting state functional connectivity in healthy adults
PubMed ID: 35670369
Memory and cognitive processing benefits suggest modest improvements in mental speed/reaction for some tasks.
- Caffeine and attentional control: improved and impaired performance in healthy older adults and Parkinson's disease according to task demands
PubMed ID: 35006304
Improved choice RT/Stroop metrics after 100 mg in withdrawn participants.
- Effects of modafinil and caffeine on night-time vigilance of air force crewmembers: A randomized controlled trial
PubMed ID: 36515156
Caffeine improved vigilance and reduced sleepiness after prolonged wakefulness—likely to support task productivity.
- The effect of mouth rinsing with different concentrations of caffeine solutions on reaction time
PubMed ID: 35193478
Caffeine mouth rinse produced large, dose-dependent improvements in hand and foot reaction times (strong, direct evidence).
- Daily Caffeine Intake and the Effect of Caffeine on Pilots' Performance After Extended Wakefulness
PubMed ID: 37726901
300 mg reduced overnight declines in psychomotor vigilance and tracking — strong effect on reaction/response performance.
- Relationship between Habitual Caffeine Consumption, Attentional Performance, and Individual Alpha Frequency during Total Sleep Deprivation
PubMed ID: 36981883
Acute caffeine improved PVT reaction time independent of habitual intake.
- Acute Cognitive Performance and Mood Effects of Coffeeberry Extract: A Randomized, Double Blind, Placebo-Controlled Crossover Study in Healthy Humans
PubMed ID: 37299382
75 mg positive control increased short‑term task performance including reaction measures.
- Ergogenic Effects of Very Low to Moderate Doses of Caffeine on Vertical Jump Performance
PubMed ID: 37414404
Very low doses improved vertical jump performance, implying faster neuromuscular responses.
- Effects of Dietary Supplementation of a Microalgae Extract Containing Fucoxanthin Combined with Guarana on Cognitive Function and Gaming Performance
PubMed ID: 37111136
Acute and 30-day use of guarana-containing supplement resulted in faster reaction times in gamers.
- Concurrent consumption of cocoa flavanols and caffeine does not acutely modulate working memory and attention
PubMed ID: 39607519
200 mg produced modestly faster temporal and spatial attention RTs (~1–3% faster).
- Effects of the active botanical blend "WKUP GT" on attention and cognitive functions after lunch in healthy volunteers
PubMed ID: 38367243
Caffeinated beverage improved multitasking performance and rapid information processing after lunch — productive task gains.
- Examining the effects of caffeine during an auditory attention task
PubMed ID: 39098270
Improved sustained attention and reduced mind‑wandering likely translate to task productivity gains.
- High-dose L-theanine-caffeine combination improves neurobehavioural and neurophysiological measures of selective attention in acutely sleep-deprived young adults: a double-blind, placebo-controlled crossover study
PubMed ID: 40789769
L‑theanine+caffeine significantly reduced reaction times and P3b latency in sleep‑deprived adults (neural and behavioral speeding).
- Transcranial direct current stimulation combined with caffeine promotes executive function in healthy females
PubMed ID: 40888092
Short‑term working memory and Stroop accuracy improvements (tDCS+CAF) could support brief productivity gains on cognitive tasks.
- Comparing Effects of Caffeine and Total Motion Release Technique on Cognitive, Neuromuscular, and Anaerobic Function in Semi-Professional Male Sprinters: A Randomized Controlled Trial
PubMed ID: 40221884
Caffeine reduced Flanker reaction times in sprinters (reliable RT speeding).
- A Randomized Study to Examine the Ability of a Caffeine-Based Energy Drink to Impact Energy Expenditure, Fat Oxidation, and Cognitive Performance
PubMed ID: 41374082
Dynavision correct‑hit improvements indicate faster/ more accurate visuomotor responding after the caffeinated drink.
Energy & Fatigue (90)
- Caffeine attenuates vasovagal reactions in female first-time blood donors
PubMed ID: 10431942
250 mg pre-donation caffeine reduced faintness/dizziness and improved willingness to continue—consistent with an acute anti-fatigue/energizing effect.
- Breakfast cereal and caffeinated coffee: effects on working memory, attention, mood, and cardiovascular function
PubMed ID: 10463623
Caffeinated coffee counteracted fatigue in the study population.
- Mood and psychomotor performance effects of the first, but not of subsequent, cup-of-coffee equivalent doses of caffeine consumed after overnight caffeine abstinence
PubMed ID: 9862086
Study reported increased energetic mood following a coffee-equivalent caffeine dose.
- Caffeine deprivation affects vigilance performance and mood
PubMed ID: 9811379
Caffeine deprivation increased fatigue in habitual drinkers, implying caffeine reduces fatigue when present.
- The impact of caffeine use on tobacco cessation and withdrawal
PubMed ID: 9022872
Stopping caffeine during smoking cessation produced increased tiredness in early abstinence — indicates caffeine reduces fatigue in habitual users.
- Caffeine withdrawal symptoms following brief caffeine deprivation
PubMed ID: 9402612
Caffeine deprivation produced increased fatigue in habitual users—indirect evidence that caffeine reduces fatigue.
- The effects of caffeine on simulated night-shift work and subsequent daytime sleep
PubMed ID: 7761739
Nighttime caffeine reduced physiological sleep propensity (objectively reduced fatigue) though performance was unchanged.
- The use of caffeine versus prophylactic naps in sustained performance
PubMed ID: 7792499
Study showed caffeine reduced sleepiness and improved performance vs placebo during sleep loss.
- An auditory attention task: a note on the processing of verbal information
PubMed ID: 8022682
Caffeine (200 mg) produced clear performance benefits after prolonged wakefulness—strong evidence for reducing fatigue-related deficits.
- Cardiovascular, behavioral, and subjective effects of caffeine under field conditions
PubMed ID: 7972294
Field study: stopping caffeine caused decreased wakefulness and activity—supports role of caffeine in reducing fatigue.
- Caffeine reversal of sleep deprivation effects on alertness and mood
PubMed ID: 7871042
High‑dose caffeine reversed sleep‑deprivation–related fatigue and restored vigor in a randomized trial.
- Effects of breakfast and caffeine on performance and mood in the late morning and after lunch
PubMed ID: 1299795
Caffeine increased alertness and cognitive performance, consistent with subjective reductions in fatigue.
- Daytime sleepiness, performance, mood, nocturnal sleep: the effect of benzodiazepine and caffeine on their relationship
PubMed ID: 2184488
Caffeine weakened the tie between sleepiness and poor mood/performance (less perceived fatigue impact).
- Genetic determinants of blood pressure responses to caffeine drinking
PubMed ID: 22170367
Physiologic increases in adrenaline and BP after caffeine are consistent with increased arousal/energy.
- Caffeine expectancies influence the subjective and behavioral effects of caffeine
PubMed ID: 19760283
Objective vigilance/psychomotor improvements and subjective effects suggest increased perceived energy.
- Metabolic effects of caffeine ingestion and physical work in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over study
PubMed ID: 16886964
Elderly subjects showed rises in epinephrine, FFAs and lactate after caffeine — adrenergic/metabolic activation compatible with energy boost.
- Situational insomnia: consistency, predictors, and outcomes
PubMed ID: 14746386
Evening dose reduced sleep efficiency but increased next-day wakefulness (reduced daytime sleepiness in susceptible subjects).
- Effect of three caffeine doses on plasma catecholamines and alertness during prolonged wakefulness
PubMed ID: 11151742
Subjective sleepiness reduced and alertness improved in dose-dependent manner—less perceived fatigue.
- Polymorphisms of ADORA2A modulate psychomotor vigilance and the effects of caffeine on neurobehavioural performance and sleep EEG after sleep deprivation
PubMed ID: 21950736
Caffeine preserved vigilance and attenuated sleep-loss related impairment in many genotypes, indicating reduced subjective/behavioral fatigue.
- In-car nocturnal blue light exposure improves motorway driving: a randomized controlled trial
PubMed ID: 23094031
Caffeinated coffee markedly reduced driving impairment during night driving, consistent with reduced functional fatigue.
- Differential cognitive effects of energy drink ingredients: caffeine, taurine, and glucose
PubMed ID: 22819803
Reduced simple and choice reaction times and improved executive function suggest reduced subjective/functional fatigue.
- Acute effects of caffeine on attention: a comparison of non-consumers and withdrawn consumers
PubMed ID: 22992376
Improvements in vigilance and reduction in long responses imply reduced cognitive fatigue acutely.
- Psychopharmacology of theobromine in healthy volunteers
PubMed ID: 23420115
200 mg caffeine produced robust stimulant-like subjective ratings (increased 'energy' and 'want').
- Caffeine can decrease subjective energy depending on the vehicle with which it is consumed and when it is measured
PubMed ID: 23455596
Caffeine increased early subjective energy in some conditions and improved cognitive performance overall.
- An evaluation of the cognitive and mood effects of an energy shot over a 6h period in volunteers: a randomized, double-blind, placebo controlled, cross-over study
PubMed ID: 23587521
Energy shot improved cognitive function and alertness in partially sleep-deprived volunteers, reducing subjective fatigue.
- A comparison of the effects of transcranial direct current stimulation and caffeine on vigilance and cognitive performance during extended wakefulness
PubMed ID: 25047826
During 30 h awake caffeine reduced some subjective and objective signs of fatigue (improved reaction times/memory latencies).
- The use of energy drinks in sport: perceived ergogenicity and side effects in male and female athletes
PubMed ID: 25212095
3 mg/kg energy drink increased self‑perceived muscle power during exercise (~+13%), a subjective 'energized' feeling.
- Effects of coffee and caffeine anhydrous on strength and sprint performance
PubMed ID: 26394649
Caffeine preserved sprint work and attenuated reductions in total work across repeated sprints—direct anti-fatigue effect in repeated-sprint context.
- Subjective and objective effects of coffee consumption - caffeine or expectations?
PubMed ID: 25481367
Subjective experience increased after 5 mg/kg caffeine, consistent with increased perceived energy.
- Caffeine increases sugar-sweetened beverage consumption in a free-living population: a randomised controlled trial
PubMed ID: 25567475
Presence of caffeine increased ad libitum SSB consumption (behavioral evidence caffeine contributes to perceived/rewarding energy intake).
- Acute personalized habitual caffeine doses improve attention and have selective effects when considering the fractionation of executive functions
PubMed ID: 26621326
Individualized morning caffeine objectively reduced subjective fatigue across 60 habitual consumers.
- Effects of a single, oral 60 mg caffeine dose on attention in healthy adult subjects
PubMed ID: 27649778
Subjective alertness/mood increased after 60 mg dose (perceived energy/arousal benefit).
- Investigating the effects of caffeine on executive functions using traditional Stroop and a new ecologically-valid virtual reality task, the Jansari assessment of Executive Functions (JEF(©))
PubMed ID: 27215836
Caffeinated coffee improved executive tasks and reaction time—indicative of reduced cognitive fatigue in some tasks.
- Caffeine, CYP1A2 Genotype, and Endurance Performance in Athletes
PubMed ID: 29509641
Caffeine improved endurance cycling times in some genotypes, implying reduced performance‑limiting fatigue (genotype‑dependent).
- Effect of single caffeine intake on neuropsychological functions in healthy volunteers: A double-blind placebo-controlled study
PubMed ID: 30379815
200 mg improved executive performance measures and RT, consistent with increased energetic drive.
- The Acute Effects of Caffeinated Black Coffee on Cognition and Mood in Healthy Young and Older Adults
PubMed ID: 30274327
100 mg coffee increased subjective alertness and attention — perceived energy boost.
- Blood dopamine level enhanced by caffeine in men after treadmill running
PubMed ID: 31793465
3 mg/kg before running increased dopamine and β-endorphin post‑exercise—neurochemical profile consistent with reduced central fatigue.
- Caffeine, exercise physiology, and time-trial performance: no effect of ADORA2A or CYP1A2 genotypes
PubMed ID: 33170731
5 mg/kg improved TT time and modestly reduced RPE versus placebo.
- Expectation for stimulant type modifies caffeine's effects on mood and cognition among college students
PubMed ID: 33734725
200 mg increased subjective stimulation and motivation — typical 'energy' sensation.
- Habitual Caffeine Consumption Does Not Interfere With the Acute Caffeine Supplementation Effects on Strength Endurance and Jumping Performance in Trained Individuals
PubMed ID: 34010807
Ergogenic improvements in jump and repetitions consistent with an acute increase in physical/subjective energy.
- Genetic Determinants of Neurobehavioral Responses to Caffeine Administration during Sleep Deprivation: A Randomized, Cross Over Study (NCT03859882)
PubMed ID: 33920292
Low-dose caffeine mitigated vigilance lapses and EEG markers during 38 h wakefulness—strong evidence for reduced subjective/functional fatigue.
- Caffeine selectively mitigates cognitive deficits caused by sleep deprivation
PubMed ID: 34014758
Caffeine restored vigilant attention after sleep deprivation, effectively reducing functional fatigue effects.
- Effects of caffeine, methylliberine, and theacrine on vigilance, marksmanship, and hemodynamic responses in tactical personnel: a double-blind, randomized, placebo-controlled trial
PubMed ID: 36016763
Vigilance improvements with 300 mg reflect reduced cognitive fatigue during tasks.
- Effects of modafinil and caffeine on night-time vigilance of air force crewmembers: A randomized controlled trial
PubMed ID: 36515156
Caffeine reduced sleepiness and improved vigilance after ~17 h awake—strong evidence of fatigue reduction.
- Bright light alone or combined with caffeine improves sleepiness in chronically sleep-restricted young drivers
PubMed ID: 35398627
Caffeine gum + bright light reduced subjective sleepiness (fatigue) and improved driving performance.
- The effect of caffeine on exercise performance is not influenced by ADORA2A genotypes, alone or pooled with CYP1A2 genotypes, in adolescent athletes
PubMed ID: 36385314
6 mg/kg produced clear performance improvements across domains (lifting, jump, Yo-Yo) consistent with increased available energy/effort capacity.
- Acute Effects of Coffee Consumption on Health among Ambulatory Adults
PubMed ID: 36947466
Coffee consumption days had higher step counts, consistent with greater daytime energy/activation.
- Daily Caffeine Intake and the Effect of Caffeine on Pilots' Performance After Extended Wakefulness
PubMed ID: 37726901
300 mg blunted overnight performance declines and reduced subjective sleepiness during extended wakefulness.
- Relationship between Habitual Caffeine Consumption, Attentional Performance, and Individual Alpha Frequency during Total Sleep Deprivation
PubMed ID: 36981883
Acute caffeine improved vigilance/RT during sleep deprivation — reduces fatigue‑related performance deficits.
- Acute Cognitive Performance and Mood Effects of Coffeeberry Extract: A Randomized, Double Blind, Placebo-Controlled Crossover Study in Healthy Humans
PubMed ID: 37299382
75 mg positive control reliably produced alerting and performance-enhancing effects consistent with feeling more energetic.
- Acute effects of caffeine supplementation on taekwondo performance: the influence of competition level and sex
PubMed ID: 37612360
3 mg/kg lowered session RPE in elite taekwondo athletes (perceived exertion/fatigue reduced).
- Acute effects of commercial energy drink consumption on exercise performance and cardiovascular safety: a randomized, double-blind, placebo-controlled, crossover trial
PubMed ID: 38197606
Commercial energy drinks (including sugar‑free caffeinated product) increased isometric impulse and raised SBP/HR — subjective/physiologic energy markers.
- Examining the effects of caffeine during an auditory attention task
PubMed ID: 39098270
Arousal/positive affect increased with 200 mg gum—translates to boosted subjective energy.
- Impact of CYP1A2 Genotypes on the Ergogenic Effects and Subjective Mood States of Caffeine Ingestion in Resistance-Trained Women
PubMed ID: 39203905
6 mg/kg improved leg‑press endurance in fast CYP1A2 metabolizers and altered subjective mood (improved in FAST subgroup).
- Acute effects of 150 mg caffeine on subjective, physiological, and behavioral components of anxiety in panic disorder and healthy controls - A randomized placebo-controlled crossover trial
PubMed ID: 40577029
150 mg increased physiological arousal (SCR), consistent with an energizing effect.
- Effects of the Combined Supplementation of Caffeine and Rhodiola Rosea with Resistance Training on Lower Limb Explosive Power in Male Volleyball Players
PubMed ID: 40005009
Rhodiola + caffeine participants reported lower RPE across 4 weeks of training (reduced perceived exertion/fatigue).
- A Randomized Study to Examine the Ability of a Caffeine-Based Energy Drink to Impact Energy Expenditure, Fat Oxidation, and Cognitive Performance
PubMed ID: 41374082
Subjects reported increased perceived energy after the caffeine‑containing energy drink (acute and Day28 timepoints).
- Acute Cardiovascular Effects of Turkish Coffee Assessed by VO(2) Test: A Randomized Crossover Trial
PubMed ID: 40077691
Caffeinated Turkish coffee increased subjective energy/attention shortly after ingestion.
- Efficacy of caffeine supplementation on fatigue in patients with multiple sclerosis: A randomized double-blind placebo-controlled trial
PubMed ID: 41406935
12‑week 100 mg/d RCT in MS produced a large, statistically significant reduction in fatigue scores (MFI‑20).
- CYP1A2 Genotype and the Ergogenic Effect of Acute Caffeine Intake on Muscular Strength and Endurance Performance in Trained Individuals
PubMed ID: 41627185
Increased repetitions and velocity indicate improved muscular endurance and delayed fatigue with 3 mg/kg caffeine in trained subjects.
- Effects of Carbohydrate Combined with Caffeine on the Sports Performance of Basketball Players
PubMed ID: 41618893
Yo‑Yo and sprint/endurance improvements indicate reduced exercise-induced fatigue with pre-exercise caffeine/carbohydrate.
- Thermoregulatory responses to exercise in the heat: chronic caffeine intake has no effect
PubMed ID: 16491580
3 mg/kg/day increased exercise endurance time, indicating reduced fatigue under heat stress.
- Enhanced mood and psychomotor performance by a caffeine-containing energy capsule in fatigued individuals
PubMed ID: 18266548
200 mg improved subjective tiredness and mood after overnight wakefulness.
- Effects of dextroamphetamine, caffeine and modafinil on psychomotor vigilance test performance after 44 h of continuous wakefulness
PubMed ID: 18522689
600 mg caffeine reduced lapses and restored vigilance after 44 h wakefulness — strong anti‑fatigue effect.
- Early effects of caffeinated and decaffeinated coffee on subjective state and gender differences
PubMed ID: 18675877
100 mg reduced somnolence and increased activation for 10–30 minutes in many participants.
- Effects of caffeine in chewing gum on mood and attention
PubMed ID: 19330801
Caffeinated gum improved mood and sustained attention at a low dose, consistent with an energy/alertness boost.
- The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness
PubMed ID: 21040626
L-theanine+caffeine reduced tiredness and increased subjective alertness in cognitive testing.
- Effects of caffeine and glucose, alone and combined, on cognitive performance
PubMed ID: 20521321
Caffeine+glucose reduced some fatigue-related task impairments while improving attention/memory measures.
- Randomized double-blind placebo-controlled crossover study of caffeine in patients with intermittent claudication
PubMed ID: 20629111
6 mg/kg caffeine acutely increased walking distance and strength in claudication patients—practical energy/performance benefit.
- Acute effects of a glucose energy drink on behavioral control
PubMed ID: 21186930
Energy drink increased subjective stimulation and improved RT—consistent with perceived energy boost (contains caffeine).
- Interaction between drug and placebo effects: a cross-over balanced placebo design trial
PubMed ID: 21092089
300 mg markedly reduced self‑reported sleepiness and increased energy in a large randomized trial.
- Expectation of having consumed caffeine can improve performance and mood
PubMed ID: 21824504
Caffeine and caffeine-expectancy increased vigour and psychomotor speed, supporting a perceived energy increase.
- Faster but not smarter: effects of caffeine and caffeine withdrawal on alertness and performance
PubMed ID: 23108937
Caffeine reversed withdrawal-related sleepiness/fatigue in a large sample.
- A comparison of tyrosine against placebo, phentermine, caffeine, and D-amphetamine during sleep deprivation
PubMed ID: 12887139
Caffeine reduced sleep drive during prolonged wakefulness — clear anti-fatigue effect in sleep-deprived participants.
- Caffeine effects on marksmanship during high-stress military training with 72 hour sleep deprivation
PubMed ID: 12688447
Under extreme sleep deprivation caffeine restored aiming speed (reduced functional fatigue) without loss of accuracy.
- A glucose-caffeine 'energy drink' ameliorates subjective and performance deficits during prolonged cognitive demand
PubMed ID: 15183925
Caffeine+glucose drinks reduced subjective mental fatigue during prolonged cognitive demand in crossover trials.
- Methylxanthines are the psycho-pharmacologically active constituents of chocolate
PubMed ID: 15549276
Cocoa methylxanthines produced measurable increases in energetic arousal (mood) vs placebo.
- Caffeine improves endurance in 75-yr-old citizens: a randomized, double-blind, placebo-controlled, crossover study
PubMed ID: 16081625
Perceived effort during cycling decreased after caffeine, consistent with reduced fatigue.
- Effects of repeated doses of caffeine on mood and performance of alert and fatigued volunteers
PubMed ID: 16272184
Dose-related performance/mood improvements were larger under fatigue, arguing caffeine reduces fatigue.
- Cognitive and mood improvements of caffeine in habitual consumers and habitual non-consumers of caffeine
PubMed ID: 15678363
Reported reductions in self-rated mental fatigue alongside cognitive benefits.
- Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Sea-Air-Land
PubMed ID: 12424548
Caffeine doses significantly reduced self‑reported fatigue/sleepiness in sleep‑deprived Navy SEAL trainees.
- Caffeine deprivation state modulates coffee consumption but not attentional bias for caffeine-related stimuli
PubMed ID: 16170233
Deprivation increased subjective drowsiness/headache, implying caffeine relieves withdrawal-related fatigue.
- Multiple caffeine doses maintain vigilance during early morning operations
PubMed ID: 16313140
200 mg every 2 h prevented overnight vigilance declines and subjective sleepiness—strong evidence for reducing fatigue under sleep loss.
- Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine users
PubMed ID: 16541243
Acute stimulant effects increased subjective arousal and positive mood.
- Laboratory and field studies of naps and caffeine as practical countermeasures for sleep-wake problems associated with night work
PubMed ID: 16453980
Caffeine (esp. with naps) decreased subjective sleepiness and improved vigilance in night-shift workers.
- The effects of caffeine, dextroamphetamine, and modafinil on humor appreciation during sleep deprivation
PubMed ID: 16796223
High-dose caffeine reduced subjective sleepiness during 49.5 h sleep deprivation.
- Effects of caffeine on performance and mood depend on the level of caffeine abstinence
PubMed ID: 12424547
Caffeine reversed withdrawal‑related fatigue and improved alertness/attention in deprived users.
- Maintaining alertness and performance during sleep deprivation: modafinil versus caffeine
PubMed ID: 11862356
High-dose caffeine maintained performance and alertness during prolonged wakefulness, indicating reduced fatigue.
- A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality
PubMed ID: 10823400
Day‑long caffeinated beverages sustained alertness and some performance, countering daytime fatigue.
- Sleep loss and temporal memory
PubMed ID: 10718074
Caffeine lowered sleepiness after 36 h awake, consistent with reduced fatigue though cognitive restoration was incomplete.
Mental clarity (61)
- The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness
PubMed ID: 21040626
Improved task-switching accuracy and alertness with L-theanine+caffeine supports clearer cognitive control.
- Caffeine, extraversion and working memory
PubMed ID: 23015541
Faster encoding and reaction time with 65 mg suggest improved mental clarity in simple tasks.
- Polymorphisms of ADORA2A modulate psychomotor vigilance and the effects of caffeine on neurobehavioural performance and sleep EEG after sleep deprivation
PubMed ID: 21950736
Caffeine preserved performance on vigilance tasks after sleep deprivation in many subjects — clearer cognitive function under sleep loss.
- In-car nocturnal blue light exposure improves motorway driving: a randomized controlled trial
PubMed ID: 23094031
Improved night-driving performance suggests clearer situational awareness and cognitive control.
- Differential cognitive effects of energy drink ingredients: caffeine, taurine, and glucose
PubMed ID: 22819803
Improvements in executive control/working memory support clearer cognitive function after 200 mg.
- Acute effects of caffeine on attention: a comparison of non-consumers and withdrawn consumers
PubMed ID: 22992376
Acute improvements in encoding speed and reaction time indicate sharper short-term mental processing.
- Psychopharmacology of theobromine in healthy volunteers
PubMed ID: 23420115
Stimulant subjective effects and improved cognitive performance metrics support enhanced mental clarity.
- Caffeine can decrease subjective energy depending on the vehicle with which it is consumed and when it is measured
PubMed ID: 23455596
Caffeine improved memory and reaction time and increased subjective clearheadedness in some conditions—supports clearer thinking acutely.
- Caffeine and cognitive decline in elderly women at high vascular risk
PubMed ID: 23422357
Prospective cohort: higher habitual caffeine associated with slower cognitive decline—consistent with long-term preservation of clarity (observational).
- Effects of two doses of glucose and a caffeine-glucose combination on cognitive performance and mood during multi-tasking
PubMed ID: 25196040
Caffeine + glucose improved multitasking and executive processing speed—translates to sharper mental clarity in complex tasks.
- Post-study caffeine administration enhances memory consolidation in humans
PubMed ID: 24413697
200 mg post‑learning enhanced memory consolidation (improved fidelity of memory could subjectively feel like clearer cognition).
- The effects of caffeine on option generation and subsequent choice
PubMed ID: 24682504
300 mg caffeine sped initial idea generation, consistent with quicker cognitive clarity on task initiation.
- Subjective and objective effects of coffee consumption - caffeine or expectations?
PubMed ID: 25481367
Subjective experience increased after caffeine suggesting improved clarity for some participants.
- Acute personalized habitual caffeine doses improve attention and have selective effects when considering the fractionation of executive functions
PubMed ID: 26621326
Improved attention and executive updating with personalized morning caffeine supports sharper cognitive clarity acutely.
- Effects of a single, oral 60 mg caffeine dose on attention in healthy adult subjects
PubMed ID: 27649778
Objective attention and reaction-time improvements support clearer/keener mental processing after 60 mg.
- Investigating the effects of caffeine on executive functions using traditional Stroop and a new ecologically-valid virtual reality task, the Jansari assessment of Executive Functions (JEF(©))
PubMed ID: 27215836
Caffeinated coffee improved executive functioning and reaction time—direct evidence consistent with sharper mental clarity.
- Low dose of caffeine enhances the efficacy of antidepressants in major depressive disorder and the underlying neural substrates
PubMed ID: 28054436
Cognitive improvements with low‑dose caffeine in depressed inpatients imply clearer thinking.
- Effect of single caffeine intake on neuropsychological functions in healthy volunteers: A double-blind placebo-controlled study
PubMed ID: 30379815
200 mg improved executive scores and reduced errors — consistent with clearer mental processing.
- The Acute Effects of Caffeinated Black Coffee on Cognition and Mood in Healthy Young and Older Adults
PubMed ID: 30274327
100 mg coffee improved attention and RT, supporting clearer mental performance.
- Influence of genetic polymorphisms and habitual caffeine intake on the changes in blood pressure, pulse rate, and calculation speed after caffeine intake: A prospective, double blind, randomized trial in healthy volunteers
PubMed ID: 30773300
Improved calculation speed supports sharper cognitive processing after caffeine.
- Cognitive enhancement effects of stimulants: a randomized controlled trial testing methylphenidate, modafinil, and caffeine
PubMed ID: 33201262
Faster sustained-attention RT and small cognitive trends after 200 mg caffeine support modest clarity gains.
- Percolating ideas: The effects of caffeine on creative thinking and problem solving
PubMed ID: 32086187
Improved convergent thinking suggests sharper task‑specific cognitive clarity after 200 mg caffeine.
- The Effects of Intraoperative Caffeine on Postoperative Opioid Consumption and Related Outcomes After Laparoscopic Surgery: A Randomized Controlled Trial
PubMed ID: 33939649
EEG markers after intraoperative caffeine suggested faster brain recovery and less early delirium — objective signs compatible with clearer cognition.
- Caffeine selectively mitigates cognitive deficits caused by sleep deprivation
PubMed ID: 34014758
Caffeine restored vigilant attention after sleep loss, which supports clearer mental functioning under sleep-deprived conditions.
- Cognitive enhancement: Effects of methylphenidate, modafinil, and caffeine on latent memory and resting state functional connectivity in healthy adults
PubMed ID: 35670369
Memory and rs‑FC improvements after single doses including caffeine support clearer cognitive processing.
- Caffeine and attentional control: improved and impaired performance in healthy older adults and Parkinson's disease according to task demands
PubMed ID: 35006304
Improvements in response selection and Stroop accuracy indicate faster/clearer mental processing post‑dose.
- Effect of caffeine on resting-state alpha activity across the human menstrual cycle
PubMed ID: 35904580
EEG arousal changes are consistent with sharper mental clarity after 200 mg.
- Bright light alone or combined with caffeine improves sleepiness in chronically sleep-restricted young drivers
PubMed ID: 35398627
Alerting, EEG and driving performance improvements indicate improved clarity under sleep restriction.
- The effect of mouth rinsing with different concentrations of caffeine solutions on reaction time
PubMed ID: 35193478
Large reaction-time improvements imply enhanced cognitive-motor clarity and responsiveness.
- Daily Caffeine Intake and the Effect of Caffeine on Pilots' Performance After Extended Wakefulness
PubMed ID: 37726901
Improved overnight vigilance and reduced sleepiness support clearer cognition during extended wakefulness.
- Relationship between Habitual Caffeine Consumption, Attentional Performance, and Individual Alpha Frequency during Total Sleep Deprivation
PubMed ID: 36981883
Acute caffeine reduced EEG slow activity and improved RT, consistent with clearer, more alert brain state.
- Acute Cognitive Performance and Mood Effects of Coffeeberry Extract: A Randomized, Double Blind, Placebo-Controlled Crossover Study in Healthy Humans
PubMed ID: 37299382
75 mg positive control increased alertness and short‑term cognitive performance suggest clearer thinking.
- Effects of Dietary Supplementation of a Microalgae Extract Containing Fucoxanthin Combined with Guarana on Cognitive Function and Gaming Performance
PubMed ID: 37111136
Reduced cognitive errors and faster reaction times suggest clearer mental processing.
- The effects of caffeine mouth rinsing on selective attention as a function of different caffeine concentrations and perceived taste intensity in recreationally active males at rest: a randomized placebo-controlled cross-over trial
PubMed ID: 39495309
Mouth‑rinse improved Stroop speed and errors, indicating clearer/ quicker selective cognition.
- Examining the effects of caffeine during an auditory attention task
PubMed ID: 39098270
Better sustained attention and less mind‑wandering implies clearer mental state with 200 mg gum.
- High-dose L-theanine-caffeine combination improves neurobehavioural and neurophysiological measures of selective attention in acutely sleep-deprived young adults: a double-blind, placebo-controlled crossover study
PubMed ID: 40789769
L‑theanine+caffeine improved attention accuracy, RT and P3b latency/amplitude, consistent with clearer, faster neural processing.
- A Randomized Study to Examine the Ability of a Caffeine-Based Energy Drink to Impact Energy Expenditure, Fat Oxidation, and Cognitive Performance
PubMed ID: 41374082
Objective Dynavision and subjective focus/energy improvements indicate clearer cognitive processing after the drink.},{
- Interactions between alcohol and caffeine in relation to psychomotor speed and accuracy
PubMed ID: 12404692
Faster psychomotor speed and partial reversal of alcohol-induced slowing support clearer mental processing.
- Caffeine expectancies influence the subjective and behavioral effects of caffeine
PubMed ID: 19760283
Improvements in vigilance and psychomotor speed imply clearer, quicker thinking.
- Effects of breakfast and caffeine on performance and mood in the late morning and after lunch
PubMed ID: 1299795
Improvements in reasoning, attention and subjective alertness support sharper cognitive clarity after caffeine.
- Does caffeine intake enhance absolute levels of cognitive performance?
PubMed ID: 7870897
Habitual caffeine associated with better reasoning and memory—supports improved clarity.
- Influence of caffeine on information processing stages in well rested and fatigued subjects
PubMed ID: 7862853
ERP evidence for increased cortical arousal/perceptual sensitivity supports clearer mental processing.
- Mood and psychomotor performance effects of the first, but not of subsequent, cup-of-coffee equivalent doses of caffeine consumed after overnight caffeine abstinence
PubMed ID: 9862086
Boosts in energetic mood and reaction speed after caffeine support sharper subjective mental clarity.
- Breakfast cereal and caffeinated coffee: effects on working memory, attention, mood, and cardiovascular function
PubMed ID: 10463623
Improved encoding and reduced fatigue with caffeinated coffee can be experienced as clearer thinking.
- A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality
PubMed ID: 10823400
Maintained CFF and some performance suggests clearer perceptual/cognitive processing across the day.
- Maintaining alertness and performance during sleep deprivation: modafinil versus caffeine
PubMed ID: 11862356
Maintained cognitive/psychomotor performance during prolonged wakefulness implies clearer mental processing.
- Effects of caffeine on performance and mood depend on the level of caffeine abstinence
PubMed ID: 12424547
Improved attention and alertness in deprived users supports subjective and objective clarity gains.
- Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Sea-Air-Land
PubMed ID: 12424548
Improvements in vigilance, RT, and learning under sleep deprivation imply clearer cognitive processing.
- Effect of three caffeine doses on plasma catecholamines and alertness during prolonged wakefulness
PubMed ID: 11151742
Objective alertness and reaction-time improvements imply sharper mental clarity.
- A glucose-caffeine 'energy drink' ameliorates subjective and performance deficits during prolonged cognitive demand
PubMed ID: 15183925
Improved sustained attention and lower mental fatigue imply clearer thinking during tasks.
- Cognitive and mood improvements of caffeine in habitual consumers and habitual non-consumers of caffeine
PubMed ID: 15678363
Consistent improvements in reaction time and working memory RT imply clearer mental processing.
- Multiple caffeine doses maintain vigilance during early morning operations
PubMed ID: 16313140
Sustained vigilance and fewer lapses overnight support clearer, more consistent cognitive performance.
- Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine users
PubMed ID: 16541243
Acute stimulant effects increased subjective arousal and vigilance but some short-term memory impairment noted.
- Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together
PubMed ID: 17891480
Subjective increases in alertness and stimulation align with improved clarity for many users.
- Effects of dextroamphetamine, caffeine and modafinil on psychomotor vigilance test performance after 44 h of continuous wakefulness
PubMed ID: 18522689
Restored PVT performance after prolonged wakefulness, indicating improved cognitive clarity under sleep loss.
- Effects of caffeine in chewing gum on mood and attention
PubMed ID: 19330801
Low-dose caffeine improved encoding speed and sustained attention, supporting sharper mental clarity.
- Effects of caffeine and glucose, alone and combined, on cognitive performance
PubMed ID: 20521321
Caffeine (with glucose) improved sustained attention/verbal memory; caffeine alone aided simple RT—indicative of cognitive clarity gains.
- Acute effects of a glucose energy drink on behavioral control
PubMed ID: 21186930
Energy drink improved RT and reduced mental fatigue, consistent with transient improvements in mental clarity (product confounds).
- Acute caffeine consumption enhances the executive control of visual attention in habitual consumers
PubMed ID: 20832925
Large improvements in vigilance and executive control at 400 mg support clearer cognitive processing.
- Expectation of having consumed caffeine can improve performance and mood
PubMed ID: 21824504
Improvements in attention and psychomotor speed indicate clearer/ faster cognitive processing with caffeine and expectancy.
- Faster but not smarter: effects of caffeine and caffeine withdrawal on alertness and performance
PubMed ID: 23108937
General alerting and motor benefits can subjectively and objectively sharpen mental clarity; habituation noted.
Pain relief (36)
- [Treating pain after dental surgery: a randomised, controlled, double-blind trial to assess a new formulation of paracetamol, opium powder and caffeine versus tramadol or placebo]
PubMed ID: 20080382
Combination analgesic including caffeine provided faster, effective postoperative pain relief vs placebo — supports caffeine as analgesic adjuvant.
- The Prophylactic Effect of Acetaminophen and Caffeine on Post Dural Puncture Headache after Spinal Anesthesia for Cesarean Section: A Randomized Double-Blind Clinical Trial
PubMed ID: 39371383
Acetaminophen+caffeine reduced post-spinal headache incidence and severity, though combination limits attribution to caffeine alone.
- The efficacy of low-level laser therapy versus paracetamol-caffeine in controlling orthodontic separation pain and changes in the oral-health-related quality of life in Class I malocclusions: A 3-arm, randomized, placebo-controlled clinical trial
PubMed ID: 35110003
Paracetamol+caffeine reduced dental pain vs placebo; caffeine is established as an analgesic adjuvant (supporting temporary pain relief).
- The Impact of Baseline Pain Intensity on the Analgesic Efficacy of Ibuprofen/Caffeine in Patients with Acute Postoperative Dental Pain: Post Hoc Subgroup Analysis of a Randomised Controlled Trial
PubMed ID: 32333328
Large RCT: adding 100 mg caffeine to 400 mg ibuprofen substantially improved analgesia in post-dental pain (supports analgesic adjuvant effect).
- Pharmacokinetic Properties of Ibuprofen (IBU) From the Fixed-Dose Combination IBU/Caffeine (400/100 mg; FDC) in Comparison With 400 mg IBU as Acid or Lysinate Under Fasted and Fed Conditions-Data From 2 Single-Center, Single-Dose, Randomized Crossover Studies in Healthy Volunteers
PubMed ID: 30897305
100 mg caffeine coformulated with ibuprofen did not change ibuprofen exposure — supports combined analgesic formulations though direct analgesic efficacy was not tested.
- Efficacy and safety of a fixed-dose combination of ibuprofen and caffeine in the management of moderate to severe dental pain after third molar extraction
PubMed ID: 28805281
Large RCT: adding 100 mg caffeine to 400 mg ibuprofen produced faster, larger and longer pain relief after dental extraction (clear analgesic adjuvant effect).
- Bioavailability of paracetamol with/without caffeine in Egyptian patients with hepatitis C virus
PubMed ID: 26888096
Caffeine added to paracetamol accelerated early absorption and altered PK, supporting faster analgesic onset (adjuvant analgesic evidence).
- Results of a multicenter, double-blind, randomized, parallel-group, placebo-controlled, single-dose study comparing the fixed combination of acetaminophen, acetylsalicylic acid, and caffeine with ibuprofen for acute treatment of patients with severe migraine
PubMed ID: 24733408
Large RCT: an analgesic combo that included caffeine relieved severe migraine faster than ibuprofen or placebo; caffeine contributed though not isolated.
- Caffeine as an adjuvant therapy to opioids in cancer pain: a randomized, double-blind, placebo-controlled trial
PubMed ID: 23498965
IV caffeine provided small but statistically significant additional pain reduction when added to opioids in advanced cancer—analgesic adjuvant evidence.
- [Observation on therapeutic effect of migraine treated with medicated threads moxibustion of Zhuang nationality]
PubMed ID: 22471135
Ergotamine+caffeine tablets reduced migraine scores vs baseline, but caffeine was part of a combination—moderate indirect support for an adjunctive effect.
- Comparison of tolerability and efficacy of a combination of paracetamol + caffeine and sumatriptan in the treatment of migraine attack: a randomized, double-blind, double-dummy, cross-over study
PubMed ID: 23054063
Paracetamol (1 g) + caffeine (130 mg) relieved migraine as effectively as sumatriptan in this trial, but caffeine was part of a combination so attribution is partial.
- Efficacy and tolerability of combined dipyrone, isometheptene and caffeine in the treatment of mild-to-moderate primary headache episodes
PubMed ID: 22288671
Combination tablets containing caffeine improved some headache outcomes vs paracetamol/control; caffeine likely contributes but was not isolated.
- The efficacy and tolerability of a fixed combination of acetylsalicylic acid, paracetamol, and caffeine in patients with severe headache: a post-hoc subgroup analysis from a multicentre, randomized, double-blind, single-dose, placebo-controlled parallel group study
PubMed ID: 21908446
Large RCT showed aspirin/paracetamol/50 mg caffeine combo was superior to placebo for severe headache; caffeine is a known analgesic adjuvant though effect cannot be isolated.
- Clinical relevance of efficacy endpoints in OTC headache trials
PubMed ID: 19472440
Meta-analysis/analysis of OTC trials (with caffeine-containing combos) links faster pain relief to better global efficacy—supports caffeine's additive role.
- Tolerability and efficacy of a combination of paracetamol and caffeine in the treatment of tension-type headache: a randomised, double-blind, double-dummy, cross-over study versus placebo and naproxen sodium
PubMed ID: 18815727
Adding 130 mg caffeine to paracetamol produced clearly superior tension‑type headache relief vs placebo — strong evidence.
- Efficacy of dosing and re-dosing of two oral fixed combinations of indomethacin, prochlorperazine and caffeine compared with oral sumatriptan in the acute treatment of multiple migraine attacks: a double-blind, double-dummy, randomised, parallel group, multicentre study
PubMed ID: 17627707
Fixed combination containing caffeine performed comparably or better than sumatriptan for migraine in a multi-agent formulation.
- Efficacy of a paracetamol and caffeine combination in the treatment of the key symptoms of primary dysmenorrhoea
PubMed ID: 17407641
Addition of 130 mg caffeine to paracetamol significantly increased pain relief for menstrual pain (analgesic adjuvant effect).
- Acetaminophen, aspirin, and caffeine in combination versus ibuprofen for acute migraine: results from a multicenter, double-blind, randomized, parallel-group, single-dose, placebo-controlled study
PubMed ID: 16618262
Two‑tablet combination containing caffeine provided faster and greater migraine relief than ibuprofen; caffeine likely contributed as an analgesic adjuvant.
- Acetaminophen, aspirin, and caffeine versus sumatriptan succinate in the early treatment of migraine: results from the ASSET trial
PubMed ID: 16109110
OTC combo including 130 mg caffeine outperformed sumatriptan for early migraine—caffeine is one component likely contributing to analgesic combo effect.
- The fixed combination of acetylsalicylic acid, paracetamol and caffeine is more effective than single substances and dual combination for the treatment of headache: a multicentre, randomized, double-blind, single-dose, placebo-controlled parallel group study
PubMed ID: 16162254
Large RCT found adding 50 mg caffeine to ASA+paracetamol sped and improved pain relief versus formulations without caffeine.
- Efficacy of a fixed combination of indomethacin, prochlorperazine, and caffeine in the treatment of episodic tension-type headache: a double-blind, randomized, nimesulide-controlled, parallel group, multicentre trial
PubMed ID: 16190913
Combination including caffeine relieved tension-type headache faster and more completely than comparator, but caffeine not isolated.
- Efficacy of diclofenac sodium softgel 100 mg with or without caffeine 100 mg in migraine without aura: a randomized, double-blind, crossover study
PubMed ID: 14756851
Addition of 100 mg caffeine to diclofenac significantly increased 60-min headache relief and reduced rescue med use in migraine attacks.
- [The effectiveness of ergotamine treatment in chronic headache disorders: a double-blind, randomized, crossover, placebo controlled trial]
PubMed ID: 14750421
Combination pill with 40 mg caffeine reduced migraine pain vs placebo; caffeine is a known analgesic adjuvant though independent contribution not isolated.
- Ibuprofen plus caffeine in the treatment of tension-type headache
PubMed ID: 11014413
Adding caffeine to ibuprofen produced faster and greater headache relief than ibuprofen alone or placebo in a large RCT—strong evidence for adjuvant analgesic effect.
- Intravenous administration of caffeine sodium benzoate for postdural puncture headache
PubMed ID: 9952095
IV caffeine reduced postdural‑puncture headache severity and analgesic demand — clear clinical headache-relief effect.
- Treatment of severe, disabling migraine attacks in an over-the-counter population of migraine sufferers: results from three randomized, placebo-controlled studies of the combination of acetaminophen, aspirin, and caffeine
PubMed ID: 10524663
Another large dataset confirming the analgesic combination including caffeine produced better pain relief and symptom improvement.
- Treatment of menstruation-associated migraine with the nonprescription combination of acetaminophen, aspirin, and caffeine: results from three randomized, placebo-controlled studies
PubMed ID: 10321417
Large trials show acetaminophen‑aspirin‑caffeine combination provides superior migraine/pain relief vs placebo; caffeine is a known adjuvant.
- Efficacy and safety of acetaminophen, aspirin, and caffeine in alleviating migraine headache pain: three double-blind, randomized, placebo-controlled trials
PubMed ID: 9482363
Three large double-blind RCTs showed robust migraine pain/symptom relief with an acetaminophen+aspirin+caffeine combination—strong evidence for caffeine as an analgesic adjuvant.
- Prophylactic intravenous administration of caffeine and recovery after ambulatory surgical procedures
PubMed ID: 9212763
IV caffeine 200 mg reduced postoperative headaches in at-risk daily caffeine users in a large randomized trial.
- [Analgesic effect and clinical tolerability of the combination of paracetamol 500 mg and caffeine 50 mg versus paracetamol 400 mg and dextropropoxyphene 30 mg in back pain]
PubMed ID: 8949620
Paracetamol plus caffeine produced clinically meaningful back-pain reduction comparable to another combo analgesic — supports caffeine as an analgesic adjuvant (applicable to temporary pain relief such as headache).
- Ibuprofen compared with ibuprofen plus caffeine after third molar surgery
PubMed ID: 8880847
Adding caffeine to ibuprofen accelerated and improved analgesia onset at 45–60 minutes (robust analgesic adjuvant evidence).
- Perioperative administration of caffeine tablets for prevention of postoperative headaches
PubMed ID: 7497559
Perioperative substitution of patients' usual caffeine prevented most immediate postoperative headaches vs placebo — strong clinical effect.
- Caffeine as an analgesic adjuvant in tension headache
PubMed ID: 7955822
Large pooled trials show ~130 mg caffeine added to analgesics produces significantly better headache relief—strong RCT evidence.
- Effect of caffeine on ibuprofen analgesia in postoperative oral surgery pain
PubMed ID: 2060256
100 mg caffeine added to ibuprofen substantially increased analgesic potency and sped onset/lengthened relief (strong evidence).
- Caffeine as an analgesic adjuvant. A double-blind study comparing aspirin with caffeine to aspirin and placebo in patients with sore throat
PubMed ID: 2012456
64 mg caffeine added to aspirin provided faster and greater sore-throat pain relief versus aspirin alone (analgesic adjuvant evidence).
- Effects of oral caffeine on postdural puncture headache. A double-blind, placebo-controlled trial
PubMed ID: 2405733
300 mg oral caffeine provided short-term relief of postdural puncture headache (significant effect at 4 h).
Workout performance (35)
- Habitual Caffeine Consumption and Training Status Affect the Ergogenicity of Acute Caffeine Intake on Exercise Performance
PubMed ID: 39905628
Pre‑exercise 3 mg/kg caffeine improved 3‑km running time and Wingate mean power in young men (robust endurance & anaerobic benefits).
- Effects of Multi-ingredient Preworkout Supplements on Physical Performance, Cognitive Performance, Mood State, and Hormone Concentrations in Recreationally Active Men and Women
PubMed ID: 32569125
Multi-ingredient preworkout including caffeine produced small increases in power and time-to-exhaustion (acute performance gains).
- The Effect of Acute Pre-Workout Supplement Ingestion on Basketball-Specific Performance of Well-Trained Athletes
PubMed ID: 37242187
Acute multi-ingredient preworkout (includes 200 mg caffeine) improved jump, agility and repeated-sprint power in trained athletes (acute performance benefit).
- Ergogenic Effects of Caffeine Consumption in a 3-min All-Out Arm Crank Test in Paraplegic and Tetraplegic Compared With Able-Bodied Individuals
PubMed ID: 26132642
Caffeine raised short‑term arm‑crank power in paraplegic athletes (group‑specific ergogenic effect).
- Evaluation of the effects of two doses of alpha glycerylphosphorylcholine on physical and psychomotor performance
PubMed ID: 29042830
200 mg caffeine modestly increased a maximal isometric force measure (IMTP peak force), indicating an acute strength benefit.
- The effects of red bull energy drink on human performance and mood
PubMed ID: 11665810
Energy-drink (contains caffeine) improved physical performance vs control, but multi-ingredient limits attribution solely to caffeine.
- Caffeine improves endurance in 75-yr-old citizens: a randomized, double-blind, placebo-controlled, crossover study
PubMed ID: 16081625
Single 6 mg/kg dose improved several endurance measures and reduced effort in cycling in older adults.
- Thermoregulatory responses to exercise in the heat: chronic caffeine intake has no effect
PubMed ID: 16491580
Chronic moderate caffeine (3 mg/kg/day) increased heat-exercise endurance (~11 min) in active men.
- The acute effects of a caffeine-containing supplement on strength, muscular endurance, and anaerobic capabilities
PubMed ID: 16937961
Acute caffeine-containing supplement increased bench-press 1RM (upper-body strength) in trained subjects.
- Caffeine has a small effect on 5-km running performance of well-trained and recreational runners
PubMed ID: 17544329
Randomized trial: 5 mg/kg caffeine produced small (~1%) but reliable faster 5‑km running times.
- Randomized double-blind placebo-controlled crossover study of caffeine in patients with intermittent claudication
PubMed ID: 20629111
6 mg/kg caffeine acutely increased walking distance and leg strength in patients with claudication (clinically meaningful physical performance gain).
- Effects of coffee and caffeine anhydrous on strength and sprint performance
PubMed ID: 26394649
Caffeine preserved sprint work and limited power loss across repeated sprints vs placebo—direct performance preservation.
- Caffeine and 3-km cycling performance: Effects of mouth rinsing, genotype, and time of day
PubMed ID: 26062916
Caffeine ingestion (and rinse) improved 3-km cycling performance by ~3–6%, with genotype/time-of-day effects—direct performance benefit.
- Effect of caffeine on exercise capacity and function in prostate cancer survivors
PubMed ID: 24977700
~6 mg/kg modestly improved short exercise (400 m) and tended to increase grip strength; accompanied by higher post‑exercise SBP/HR.
- Placebo in sports nutrition: a proof-of-principle study involving caffeine supplementation
PubMed ID: 27882605
6 mg/kg improved 30-min cycling TT ≈+4% in trained cyclists (direct ergogenic evidence).
- Caffeine, CYP1A2 Genotype, and Endurance Performance in Athletes
PubMed ID: 29509641
2–4 mg/kg caffeine robustly improved 10‑km cycling time in AA CYP1A2 carriers (up to −6.8%); genotype‑dependent.
- The effect of CYP1A2 genotype on the ergogenic properties of caffeine during resistance exercise: a randomized, double-blind, placebo-controlled, crossover study
PubMed ID: 29532291
6 mg/kg increased resistance-exercise repetitions/total work in CYP1A2 AA homozygotes (genotype-dependent ergogenicity).
- Coffee Ingestion Improves 5 km Cycling Performance in Men and Women by a Similar Magnitude
PubMed ID: 31731467
Caffeinated coffee (3 mg/kg) improved 5 km cycling time ~1.8–1.9% in crossover trial—clear endurance performance benefit.
- Caffeine, exercise physiology, and time-trial performance: no effect of ADORA2A or CYP1A2 genotypes
PubMed ID: 33170731
5 mg/kg improved ~30-min cycling TT performance and related physiological markers.
- Effect of Caffeine on Endurance Performance in Athletes May Depend on HTR2A and CYP1A2 Genotypes
PubMed ID: 32569126
4 mg/kg improved 10-km cycling times in a large sample (genotype-moderated effects).
- Habitual Caffeine Consumption Does Not Affect the Ergogenicity of Coffee Ingestion During a 5 km Cycling Time Trial
PubMed ID: 33260141
Caffeinated coffee (≈3 mg/kg) improved 5‑km cycling time vs control (ergogenic effect).
- Caffeine improves various aspects of athletic performance in adolescents independent of their 163 C > A CYP1A2 genotypes
PubMed ID: 32538495
6 mg/kg improved muscular endurance and aerobic performance in adolescent athletes.
- Caffeine-Induced Effects on Human Skeletal Muscle Contraction Time and Maximal Displacement Measured by Tensiomyography
PubMed ID: 33801251
9 mg/kg acutely changed muscle contractile properties (shorter contraction time), supporting faster muscle performance.
- Habitual Caffeine Consumption Does Not Interfere With the Acute Caffeine Supplementation Effects on Strength Endurance and Jumping Performance in Trained Individuals
PubMed ID: 34010807
6 mg/kg improved jump height and strength‑endurance repetitions — strong, consistent ergogenic evidence.
- The effect of mouth rinsing with different concentrations of caffeine solutions on reaction time
PubMed ID: 35193478
Caffeine mouth rinse produced large RT improvements which can translate to quicker sport responses (direct physical-output effects not tested).
- The effect of caffeine on exercise performance is not influenced by ADORA2A genotypes, alone or pooled with CYP1A2 genotypes, in adolescent athletes
PubMed ID: 36385314
6 mg/kg improved strength, jump and intermittent endurance in adolescent athletes (robust multi-domain ergogenic effects).
- Effect of isolated and combined ingestion of caffeine and citrulline malate on resistance exercise and jumping performance: a randomized double-blind placebo-controlled crossover study
PubMed ID: 37450275
5 mg/kg increased bench‑press 1RM and repetitions-to-failure for squat and bench — robust strength/endurance benefit.
- Ergogenic Effects of Very Low to Moderate Doses of Caffeine on Vertical Jump Performance
PubMed ID: 37414404
Very low to moderate caffeine doses (including 1 mg/kg) improved vertical jump — benefit for explosive performance.
- Acute effects of caffeine supplementation on taekwondo performance: the influence of competition level and sex
PubMed ID: 37612360
3 mg/kg improved sport-specific agility and kicking performance in taekwondo athletes.
- Sex Differences in the Ergogenic Response of Acute Caffeine Intake on Muscular Strength, Power and Endurance Performance in Resistance-Trained Individuals: A Randomized Controlled Trial
PubMed ID: 38892692
~3 mg/kg improved velocity, power and muscular endurance across loads in trained men/women.
- Sex differences in the acute effect of caffeine on repeated sprint performance: A randomized controlled trial
PubMed ID: 39662990
Triple‑blind RCT: 3 mg/kg raised peak and mean sprint power (~3–5%), consistent ergogenic effect.
- Effects of the Combined Supplementation of Caffeine and Rhodiola Rosea with Resistance Training on Lower Limb Explosive Power in Male Volleyball Players
PubMed ID: 40005009
Rhodiola + caffeine across 4 weeks improved explosive jump measures during training versus placebo (practical ergogenic benefit).
- Caffeine Combined with Excitatory Neuromodulation Based on Transcranial Direct Current Stimulation (tDCS) Enhances Performance in a Time-Trial CrossFit(®) Workout: A Randomized, Placebo-Controlled, Double-Blind Study
PubMed ID: 40219021
400 mg caffeine + anodal tDCS shortened CrossFit benchmark time more than placebo/sham (sport‑specific performance gain).
- CYP1A2 Genotype and the Ergogenic Effect of Acute Caffeine Intake on Muscular Strength and Endurance Performance in Trained Individuals
PubMed ID: 41627185
Well-powered crossover showed acute 3 mg/kg caffeine increased mean velocity and repetitions in resistance-trained subjects (clear ergogenic effect).
- Effects of Carbohydrate Combined with Caffeine on the Sports Performance of Basketball Players
PubMed ID: 41618893
Pre‑exercise caffeine (with/without carbs) improved CMJ, 20 m sprint and Yo‑Yo intermittent performance in basketball players.
Endurance (30)
- The effect of caffeine on exercise performance is not influenced by ADORA2A genotypes, alone or pooled with CYP1A2 genotypes, in adolescent athletes
PubMed ID: 36385314
6 mg/kg significantly increased Yo-Yo IR1 distance (~10.7%), indicating greater intermittent endurance capacity.
- Habitual Caffeine Consumption Does Not Interfere With the Acute Caffeine Supplementation Effects on Strength Endurance and Jumping Performance in Trained Individuals
PubMed ID: 34010807
Improved repetitions (strength endurance) and jump performance indicate better stamina/endurance capacity.
- Caffeine improves various aspects of athletic performance in adolescents independent of their 163 C > A CYP1A2 genotypes
PubMed ID: 32538495
6 mg/kg improved aerobic performance (Yo-Yo IR1) in adolescent athletes.
- Habitual Caffeine Consumption Does Not Affect the Ergogenicity of Coffee Ingestion During a 5 km Cycling Time Trial
PubMed ID: 33260141
Improved 5‑km time demonstrates a measurable endurance improvement in cycling.
- Effect of Caffeine on Endurance Performance in Athletes May Depend on HTR2A and CYP1A2 Genotypes
PubMed ID: 32569126
4 mg/kg improved 10-km cycling times in many athletes (endurance effect; genotype interactions).
- Caffeine, exercise physiology, and time-trial performance: no effect of ADORA2A or CYP1A2 genotypes
PubMed ID: 33170731
5 mg/kg improved ~30-min TT performance (endurance marker).
- Coffee Ingestion Improves 5 km Cycling Performance in Men and Women by a Similar Magnitude
PubMed ID: 31731467
3 mg/kg coffee improved 5 km cycling TT ~1.9% in men and women—clear endurance enhancement.
- The effect of CYP1A2 genotype on the ergogenic properties of caffeine during resistance exercise: a randomized, double-blind, placebo-controlled, crossover study
PubMed ID: 29532291
Increased resistance-exercise volume in AA genotype suggests improved capacity/endurance for those individuals.
- Caffeine, CYP1A2 Genotype, and Endurance Performance in Athletes
PubMed ID: 29509641
Caffeine produced substantial 10‑km time improvements in responders, a clear endurance benefit (genotype‑dependent).
- Placebo in sports nutrition: a proof-of-principle study involving caffeine supplementation
PubMed ID: 27882605
30-min TT performance improved ~4% in trained cyclists (endurance/stamina evidence).
- Effect of caffeine on exercise capacity and function in prostate cancer survivors
PubMed ID: 24977700
~6 mg/kg improved 400 m capacity ~3% — evidence for increased short‑duration endurance.
- Caffeine and 3-km cycling performance: Effects of mouth rinsing, genotype, and time of day
PubMed ID: 26062916
3-km cycling improvements reflect better short-to-moderate endurance (genotype/time-of-day effects).
- Sex differences in the acute effect of caffeine on repeated sprint performance: A randomized controlled trial
PubMed ID: 39662990
Repeated Wingate sprints: caffeine increased mean and peak power across sprints, supporting repeated‑effort stamina.
- Randomized double-blind placebo-controlled crossover study of caffeine in patients with intermittent claudication
PubMed ID: 20629111
6 mg/kg caffeine increased maximal walking distance by ~26.6% in intermittent claudication—clear endurance improvement for walking.
- Caffeine has a small effect on 5-km running performance of well-trained and recreational runners
PubMed ID: 17544329
Small improvement in 5‑km time indicates modest enhancement of endurance performance with ~5 mg/kg caffeine.
- Thermoregulatory responses to exercise in the heat: chronic caffeine intake has no effect
PubMed ID: 16491580
Chronic moderate caffeine increased heat-exercise tolerance time substantially versus control.
- Caffeine improves endurance in 75-yr-old citizens: a randomized, double-blind, placebo-controlled, crossover study
PubMed ID: 16081625
Endurance improved in cycling/arm tasks in older adults after caffeine.
- Ergogenic Effects of Caffeine Consumption in a 3-min All-Out Arm Crank Test in Paraplegic and Tetraplegic Compared With Able-Bodied Individuals
PubMed ID: 26132642
Power increases in paraplegic athletes suggest improved short‑duration muscular stamina in that group.
- The Effect of Acute Pre-Workout Supplement Ingestion on Basketball-Specific Performance of Well-Trained Athletes
PubMed ID: 37242187
Acute improvements in repeated-sprint power and decreased fatigue index after a caffeine-containing preworkout indicate better short-term endurance.
- Effects of Multi-ingredient Preworkout Supplements on Physical Performance, Cognitive Performance, Mood State, and Hormone Concentrations in Recreationally Active Men and Women
PubMed ID: 32569125
Preworkout with caffeine increased anaerobic power and time-to-exhaustion acutely (supports improved endurance in short tests).
- Effects of Carbohydrate Combined with Caffeine on the Sports Performance of Basketball Players
PubMed ID: 41618893
Endurance test (Yo‑Yo IRL1) improved with caffeine/carbohydrate, consistent with greater physical endurance.
- CYP1A2 Genotype and the Ergogenic Effect of Acute Caffeine Intake on Muscular Strength and Endurance Performance in Trained Individuals
PubMed ID: 41627185
Repeated-repetition increases indicate better muscular endurance with 3 mg/kg caffeine in trained subjects.
- Effects of the Combined Supplementation of Caffeine and Rhodiola Rosea with Resistance Training on Lower Limb Explosive Power in Male Volleyball Players
PubMed ID: 40005009
Participants reported reduced RPE across 4 weeks of training with Rhodiola+caffeine (subjective exertion decrease).
- Habitual Caffeine Consumption and Training Status Affect the Ergogenicity of Acute Caffeine Intake on Exercise Performance
PubMed ID: 39905628
3 mg/kg improved 3‑km running time (endurance) in a well‑powered trial.
- ACE gene polymorphisms (rs4340) II and DI are more responsive to the ergogenic effect of caffeine than DD on aerobic power, heart rate, and perceived exertion in a homogeneous Brazilian group of adolescent athletes
PubMed ID: 38896643
Adolescent athletes showed genotype‑dependent increases in Yo‑Yo intermittent endurance after 6 mg/kg caffeine.
- Effects of coffee and caffeine anhydrous on strength and sprint performance
PubMed ID: 26394649
Caffeine preserved sprint work across repeated sprints, supporting endurance in repeated high-intensity efforts.
- Sex Differences in the Ergogenic Response of Acute Caffeine Intake on Muscular Strength, Power and Endurance Performance in Resistance-Trained Individuals: A Randomized Controlled Trial
PubMed ID: 38892692
Consistent velocity/power and repetition improvements across loads support endurance capacity.
- Acute effects of caffeine supplementation on taekwondo performance: the influence of competition level and sex
PubMed ID: 37612360
Session RPE was lowered after 3 mg/kg caffeine in elite taekwondo athletes.
- Ergogenic Effects of Very Low to Moderate Doses of Caffeine on Vertical Jump Performance
PubMed ID: 37414404
Even 1 mg/kg improved vertical jump height, consistent with improved explosive stamina/power.
- Effect of isolated and combined ingestion of caffeine and citrulline malate on resistance exercise and jumping performance: a randomized double-blind placebo-controlled crossover study
PubMed ID: 37450275
Improved repetitions‑to‑failure for squat and bench reflect increased muscular endurance.
Mood balance (25)
- Cognitive and mood improvements of caffeine in habitual consumers and habitual non-consumers of caffeine
PubMed ID: 15678363
Reported increased alertness and decreased mental fatigue which often correspond to improved mood.
- Daytime sleepiness, performance, mood, nocturnal sleep: the effect of benzodiazepine and caffeine on their relationship
PubMed ID: 2184488
Caffeine lessened the link between sleepiness and poorer mood, indicating mood-stabilizing subjective effects.
- Caffeine reversal of sleep deprivation effects on alertness and mood
PubMed ID: 7871042
High‑dose caffeine after sleep loss restored mood subscales toward rested levels in RCT.
- Illustrating caffeine's pharmacological and expectancy effects utilizing a balanced placebo design
PubMed ID: 8991966
Balanced‑placebo study found both actual caffeine and the belief of having consumed it affected mood ratings (direct evidence).
- Conditioned flavour preferences reinforced by caffeine consumed after lunch
PubMed ID: 8804673
Caffeine relieved post-lunch dip and conditioned flavor preference via mood improvement in habitual users.
- Mood and psychomotor performance effects of the first, but not of subsequent, cup-of-coffee equivalent doses of caffeine consumed after overnight caffeine abstinence
PubMed ID: 9862086
Energetic mood increased after caffeine, indicating a modest mood-lifting effect.
- [Experimental study of the effect of acetylsalicylic acid combined with caffeine regarding possible abuse potential]
PubMed ID: 11486635
In habitual coffee drinkers caffeine reduced negative mood scores in a relatively large sample.
- Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Sea-Air-Land
PubMed ID: 12424548
Caffeine reduced fatigue/sleepiness in trainees; improved affect/mood may accompany reduced sleepiness under stress.
- Caffeine reinforces flavour preference in caffeine-dependent, but not long-term withdrawn, caffeine consumers
PubMed ID: 12589525
Caffeine maintained users showed increased liking for a flavored drink, indicating reinforcement that can reflect mood/hedonic effects.
- Subjective effects of slow-release bupropion versus caffeine as determined in a quasi-naturalistic setting
PubMed ID: 15001822
Caffeine produced modest increases in pleasant feelings and 'high' ratings in smokers (acute mood-lifting effect).
- Cognitive and psychomotor performance, mood, and pressor effects of caffeine after 4, 6 and 8 h caffeine abstinence
PubMed ID: 15696321
Second dose improved mood and cognitive performance only after ~8 h abstinence; time-dependent.
- Effects of repeated doses of caffeine on mood and performance of alert and fatigued volunteers
PubMed ID: 16272184
Demonstrated linear dose-related improvements in positive mood and performance, especially when fatigued.
- Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine users
PubMed ID: 16541243
Reported increases in subjective arousal/positive mood after acute caffeine.
- Enhanced mood and psychomotor performance by a caffeine-containing energy capsule in fatigued individuals
PubMed ID: 18266548
200 mg increased vigor (POMS) in sleep‑deprived subjects — clear mood elevation.
- Effects of caffeine in chewing gum on mood and attention
PubMed ID: 19330801
40 mg caffeinated gum improved positive affect versus placebo/no gum (clear mood benefit).
- Expectation of having consumed caffeine can improve performance and mood
PubMed ID: 21824504
Expectation and caffeine improved vigour and moderated depression scores—mood benefits partly pharmacologic and partly expectancy-driven.
- Caffeine improves left hemisphere processing of positive words
PubMed ID: 23144893
200 mg caffeine selectively improved recognition accuracy for positive words (suggesting a modest positive affective bias).
- Psychopharmacology of theobromine in healthy volunteers
PubMed ID: 23420115
Caffeine produced stimulant subjective effects that often include improved mood/positive valence (measured as 'feel/high/like').
- Caffeine can decrease subjective energy depending on the vehicle with which it is consumed and when it is measured
PubMed ID: 23455596
Mood effects varied by vehicle/time but early increases in energy/clearheadedness observed with caffeine in some conditions.
- Effects of a single, oral 60 mg caffeine dose on attention in healthy adult subjects
PubMed ID: 27649778
Subjective alertness/mood increased alongside cognitive improvements after 60 mg.
- Low dose of caffeine enhances the efficacy of antidepressants in major depressive disorder and the underlying neural substrates
PubMed ID: 28054436
Adjunct low‑dose caffeine in depressed inpatients produced faster symptom improvement and cognitive gains.
- Blood dopamine level enhanced by caffeine in men after treadmill running
PubMed ID: 31793465
Post-exercise increases in β-endorphin and dopamine after 3 mg/kg may favorably influence mood and reduce central fatigue.
- Habitual caffeine consumption moderates the antidepressant effect of dorsomedial intermittent theta-burst transcranial magnetic stimulation
PubMed ID: 34872405
Higher habitual caffeine intake predicted better antidepressant response to dmPFC iTBS (observational moderation).
- The Impact of Caffeine Intake on Mental Health Symptoms in Postmenopausal Females with Overactive Bladder Symptoms: A Randomized, Double-Blind, Placebo-Controlled Trial
PubMed ID: 35363563
400 mg/day caffeine produced a small reduction in anxiety in postmenopausal women.
- Efficacy of caffeine supplementation on fatigue in patients with multiple sclerosis: A randomized double-blind placebo-controlled trial
PubMed ID: 41406935
100 mg/day for 12 weeks improved QoL domains including emotional well‑being in MS patients (mood benefit).
Metabolism (13)
- Herbal ephedra/caffeine for weight loss: a 6-month randomized safety and efficacy trial
PubMed ID: 12032741
Ephedra/caffeine produced greater weight/fat loss vs placebo over 6 months (confounded by ephedrine; metabolic implication).
- Metabolic effects of caffeine ingestion and physical work in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over study
PubMed ID: 16886964
Elderly participants showed increases in epinephrine, FFAs and lactate with caffeine, consistent with increased lipolysis/metabolic rate.
- The acute effects of thermogenic fitness drink formulas containing 140 mg and 100 mg of caffeine on energy expenditure and fat metabolism at rest and during exercise
PubMed ID: 32054486
Thermogenic drinks with 100–140 mg caffeine acutely increased resting energy expenditure and the 140 mg dose increased fat oxidation (direct RMR data).
- Modification of subcutaneous adipose tissue by a methylxanthine formulation: a double-blind controlled study
PubMed ID: 10469092
Topical liposome-encapsulated caffeine cream reduced subcutaneous fat thickness over 2 months, indicating local lipolytic/metabolic effects.
- Effect of a dietary herbal supplement containing caffeine and ephedra on weight, metabolic rate, and body composition
PubMed ID: 15292480
Caffeine+ephedra product increased resting metabolic rate (~+8% acutely) and produced greater short-term weight/fat loss, but ephedra confounds attribution.
- Regularly consuming a green/roasted coffee blend reduces the risk of metabolic syndrome
PubMed ID: 27738812
Coffee blend (≈121 mg caffeine/day) lowered fasting glucose, HOMA-IR and triglycerides over 8 weeks (metabolic marker changes).
- The effect of coffee consumption on insulin sensitivity and other biological risk factors for type 2 diabetes: a randomized placebo-controlled trial
PubMed ID: 31891374
24-week caffeinated coffee (4 cups/day) associated with small fat-mass loss—suggestive of modest metabolic effects.
- Effect of Coffee and Tea Consumption on Adolescent Weight Control: An Interventional Pilot Study
PubMed ID: 35639365
Coffee plus family counseling associated with notable BMI reduction in adolescents (confounded by counseling but consistent with metabolic/behavioral effect).
- Chronic Thermogenic Dietary Supplement Consumption: Effects on Body Composition, Anthropometrics, and Metabolism
PubMed ID: 38004200
Four weeks of protein plus caffeinated thermogenic supplement prevented a small drop in resting energy expenditure vs control.
- Influence of the CYP1A2 c.(-163) A > C polymorphism in the effect of caffeine on fat oxidation during exercise: a pilot randomized, double-blind, crossover, placebo-controlled trial
PubMed ID: 39007997
3–6 mg/kg increased fat oxidation during moderate‑intensity cycling (~40–50% VO2max) across CYP1A2 genotypes (clear metabolic effect).
- Phase 1 Studies to Assess Inhaled Seralutinib as a Perpetrator or a Victim of Drug-Drug Interactions in Healthy Participants
PubMed ID: 39711098
Seralutinib raised caffeine AUC (PK interaction) — indirect effect on apparent caffeine metabolism/exposure.
- Combination Effect of Caffeine Intake and Thermotherapy on the Blood Levels of Human Irisin and Fibroblast Growth Factor 21 in Healthy Males
PubMed ID: 40635261
Caffeine before hot bath amplified increases in thermogenesis biomarkers (FGF‑21, irisin) and body/skin temperature — mechanistic support for increased metabolic activity.
- A Randomized Study to Examine the Ability of a Caffeine-Based Energy Drink to Impact Energy Expenditure, Fat Oxidation, and Cognitive Performance
PubMed ID: 41374082
Caffeine‑containing energy drink acutely and over 28 days raised resting energy expenditure (thermogenic effect) and transiently increased fat oxidation.
Motivation & confidence (5)
- Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Sea-Air-Land
PubMed ID: 12424548
Reduced fatigue and improved performance under severe stress likely increase ability and willingness to perform (motivation proxy).
- Expectation for stimulant type modifies caffeine's effects on mood and cognition among college students
PubMed ID: 33734725
Caffeine increased subjective feelings of motivation/stimulation vs placebo.
- Psychopharmacology of theobromine in healthy volunteers
PubMed ID: 23420115
Caffeine increased 'want'/'like' subjective ratings (stimulant profile) which may reflect short-term motivational drive.
- Faster but not smarter: effects of caffeine and caffeine withdrawal on alertness and performance
PubMed ID: 23108937
Improved alertness and performance may indirectly support motivation, though not directly measured.
- Expectation of having consumed caffeine can improve performance and mood
PubMed ID: 21824504
Expectation increased vigour and some mood measures—psychological drivers that can boost motivation.
Forms of Caffeine
The form a label may print instead of Caffeine. Each is a different substance with its own identifier, and none of them has research of its own — the studies are the ones on this page.
Similar by evidence
Supplements the same benefits carry qualifying findings for — a fact about the evidence graph, not a recommendation to swap.
Products with Caffeine
Search all1986 products whose verified label declares Caffeine — not every bottle that mentions it in a title.
Being studied right now
Recruiting clinical trials registered on ClinicalTrials.gov. A trial in progress has no result yet — this is what the field is asking, not what it found.