Tryptophan and Essential Amino Acids: study protocols
12 study groups took Tryptophan together with Essential Amino Acids. These are the doses the studies gave. They are not a recommendation.
Dose per serving from research: Tryptophan
10 study groups in 9 studies say how much Tryptophan participants took a day.
These are the doses the studies gave. They are not a recommendation.
Most common: 1 g to 2.5 g, 50% of 10 study groups.
| Daily dose | Study groups |
|---|---|
| 500 mg to 1 g | 1 |
| 1 g to 2.5 g | 5 |
| 2.5 g to 5 g | 1 |
| 5 g to 10 g | 2 |
| over 10 g | 1 |
Dose per serving from research: Essential Amino Acids
6 study groups in 6 studies say how much Essential Amino Acids participants took a day.
These are the doses the studies gave. They are not a recommendation.
Most common: 50 g to 100 g, 50% of 6 study groups.
| Daily dose | Study groups |
|---|---|
| 10 g or less | 1 |
| 10 g to 25 g | 0 |
| 25 g to 50 g | 2 |
| 50 g to 100 g | 3 |
Commonly used together
4 of 12 study groups took Tryptophan and Essential Amino Acids with something else, but nothing that 3 or more different studies gave.
12 study groups
| Study | ||||
|---|---|---|---|---|
| Effects of tryptophan depletion and a simulated alcohol binge on impulsivity 2015 · Tryptophan-balanced control followed by alcohol · Adults aged 26–54 who drank at least once per week, without stated clinically significant medical or psychological conditions | 5.15 g | — | 1 day | 179 |
| Effects of tryptophan depletion and a simulated alcohol binge on impulsivity 2015 · Tryptophan-balanced control followed by placebo · Adults aged 26–54 who drank at least once per week, without stated clinically significant medical or psychological conditions | 5.15 g | — | 1 day | 179 |
| The effects of tryptophan depletion on neural responses to emotional words in remitted depression 2009 · TRP+ · Adults aged 18–50: 23 unmedicated participants with remitted major depressive disorder and 20 healthy controls | 1.2 g | 31.5 g | 1 day | 43 |
| Serotonin transporter polymorphism mediates vulnerability to loss of incentive motivation following acute tryptophan depletion 2006 · TRP+ · Healthy adults with 5-HTTLPR ll or ss genotype, without a history of Axis I psychiatric disorders | 3 g | 78 g | 1 day | 30 |
| Facial expressions of pain: the role of the serotonergic system 2023 · Control (Trp+) condition · Adult women, mean age 24.1 years, without current or past psychiatric or neurological disorders or acute or chronic pain | 10.3 g | — | 1 day | 27 |
| An fMRI study on the role of serotonin in reactive aggression 2011 · BAL (balanced amino acid drink containing tryptophan) · Healthy male volunteers; mean age 24.7 years; no stated diagnosed condition | 2.3 g | 100 g | 1 day | 15 |
| Acute tryptophan depletion attenuates conscious appraisal of social emotional signals in healthy female volunteers 2011 · Control mixture · Healthy female volunteers, aged 19–34; no stated psychiatric condition | 1.92 g | 49.9 g | 1 day | 15 |
| CSF neurochemicals during tryptophan depletion in individuals with remitted depression and healthy controls 2010 · Sham condition · Adults aged 23–60: people with remitted major depressive episode and healthy controls | 2.3 g | — | 3 days | 24 |
| Time series fMRI measures detect changes in pontine raphé following acute tryptophan depletion 2011 · Control balanced amino acid diet including tryptophan · Adults aged 21–49 in remission from prior depression while taking serotonin reuptake inhibitor antidepressants | 2.3 g | 100 g | 1 day | 11 |
| Melatonin and dopamine as biomarkers to optimize treatment in phenylketonuria: effects of tryptophan and tyrosine supplementation 2014 · LNAA + placebo (LNAA phase) · Adults aged 21–51 years with classical phenylketonuria; 2 women and 8 men enrolled | 30.6 mg/kg | 104 mg/kg | 3 weeks | 10 |
| Melatonin and dopamine as biomarkers to optimize treatment in phenylketonuria: effects of tryptophan and tyrosine supplementation 2014 · LNAA + Trp/Tyr (LNAA + TT phase) · Adults aged 21–51 years with classical phenylketonuria; 2 women and 8 men enrolled | 69.4 mg/kg | 104 mg/kg | 3 weeks | 10 |
| Acute tryptophan depletion in accordance with body weight: influx of amino acids across the blood-brain barrier 2012 · Balanced amino acid load (BAL) · Healthy adults aged 21–30 years, male and female | 700 mg | 6.5 g | 1 day | 24 |