supp.fit

L-Methionine

17 benefits mapped to clinical evidence across supplements.

Serves the goals:Bone & JointCognitionDetoxEnergyEssential Health

Dose per serving from products

2,091 products in our catalogue print how much L-Methionine a serving holds.

Most common: 100 mg to 250 mg, 18% of 2,091 products.

Dose per servingProducts
5 mg or less
29
5 mg to 10 mg
139
10 mg to 25 mg
269
25 mg to 50 mg
234
50 mg to 100 mg
306
100 mg to 250 mg
367
250 mg to 500 mg
314
500 mg to 1 g
352
over 1 g
81

Dose per serving from research

53 study groups in 20 studies say how much L-Methionine participants took a day.

These are the doses the studies gave. They are not a recommendation.

Most common: 50 mg/kg to 100 mg/kg, 32% of 53 study groups.

Daily doseStudy groups
0.5 mg/kg or less
2
0.5 mg/kg to 1 mg/kg
2
1 mg/kg to 2.5 mg/kg
3
2.5 mg/kg to 5 mg/kg
5
5 mg/kg to 10 mg/kg
6
10 mg/kg to 25 mg/kg
11
25 mg/kg to 50 mg/kg
7
50 mg/kg to 100 mg/kg
17

See every study group

Commonly used together

37 of 82 study groups took L-Methionine with something else. Shown: what 3 or more different studies gave.

What was given together, not what works together.

Taken withStudy groups
Cysteine
9
Essential Amino Acids
9
Cystine
5
Vitamin C
5
Vitamin E
3

Benefit Evidence

Cell health
Strong

Choline depletion ↑ALT

Homocysteine ↓ with supplements

13,042 people
Liver support
Strong

ALT/cholestasis ↓

Fibrosis risk ↓

Liver prediction +0.06

3,405 people
Detoxification
Strong

GSH/Cysteine detoxification

Homocysteine lowering

4,232 people
Metabolism
Strong

Lipids ↑ with methionine

Homocysteine ↑; vessel function ↓

Methionine restriction: fat loss

6,079 people
Muscle growth
Strong

Muscle protein synthesis +

Growth + weight gain

Amino acids + methionine

6,484 people
Antioxidant
Strong

Glutathione↑, MDA↓

Selenium/antioxidants↑

2,135 people
Healthy aging
Strong

Homocysteine↓, risk↓

Methylation↑, aging↓

3,201 people
Brain health
Moderate

Memory/executive +0.84

+ methylation/choline

Depression response +18.5%

1,624 people
Mood balance
Moderate

Depression ↓; remiss. +18.5pp

Mood stable; biomarkers ↑500%

Male benefit d=0.95

1,598 people
Immune support
Moderate

Leukocyte/antibody boosts

−55% anti‑TPO

−34pp mucositis

1,515 people
Nutrition source
Moderate

Met boost; AA markers

Cys spares Met need

1,765 people
Hormone balance
Moderate

Immune ↓; TgAb −

Inflammation ↓; Steroidogenesis ↑

2,696 people
Digestive support
Moderate

Digestive diges.+VFA

Symptoms/ulcer relapse

Mucositis -24%

1,777 people
Joint comfort
Moderate

Pain relief similar vs NSAIDs

Tenderness down; liver enzymes +

336 people
Energy & Fatigue
Moderate

Methionine: DMI, milk, protein

Fatigue: cycling +1.4 min

346 people
Skin appearance
Weak

Faster healing, fewer relapses

Lesion scores down

Ulcer healing +23pp

294 people
Hair & Nails
Weak

Hair outcomes +1.01

Wool traits, methionine

83 people

Research sources

Cell health (63)
  1. 5,10-Methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTRR), and methionine synthase reductase (MTR) gene polymorphisms and adult meningioma risk

    PubMed ID: 23959833

    Large genetic case–control study found folate/methionine pathway variants associated with meningioma risk—supports importance of methionine‑related methylation genetics.

  2. The association of betaine, homocysteine and related metabolites with cognitive function in Dutch elderly people

    PubMed ID: 17537289

    B12+folate reduced homocysteine and raised betaine → supports one‑carbon/methylation metabolism.

  3. Choline intake exceeding current dietary recommendations preserves markers of cellular methylation in a genetic subgroup of folate-compromised men

    PubMed ID: 20220206

    Higher choline intake maintained SAMe and DNA methylation in folate‑compromised men → direct support for methylation capacity.

  4. Maternal choline intake modulates maternal and fetal biomarkers of choline metabolism in humans

    PubMed ID: 22418088

    Maternal choline increased methyl‑donor metabolites including changes in methionine → relevant to methylation pathways.

  5. Hepatic Activity and Transcription of Betaine-Homocysteine Methyltransferase, Methionine Synthase, and Cystathionine Synthase in Periparturient Dairy Cows Are Altered to Different Extents by Supply of Methionine and Choline

    PubMed ID: 27881594

    Rumen‑protected methionine markedly changed hepatic methylation‑related gene expression and enzyme activity (MAT1A, PEMT, SAHH, CBS).

  6. Effects of rumen-protected methionine and choline supplementation on the preimplantation embryo in Holstein cows

    PubMed ID: 26928647

    Peripartal methionine altered embryo global DNA methylation (direct evidence of methylation effects).

  7. Eggs early in complementary feeding increase choline pathway biomarkers and DHA: a randomized controlled trial in Ecuador

    PubMed ID: 29092879

    One‑egg/day increased plasma methionine in infants (raises substrate for SAM synthesis and methylation reactions).

  8. Traditional Korean diet high in one-carbon nutrients increases global DNA methylation: implication for epigenetic diet

    PubMed ID: 38867083

    Traditional Korean diet increased global DNA methylation and altered homocysteine/folate—one‑carbon pathway evidence.

  9. The effect of L-arginine and creatine on vascular function and homocysteine metabolism

    PubMed ID: 19651674

    Arginine/creatine supplementation changed methylation metabolites (including methionine decreases and homocysteine increases), demonstrating perturbation of methylation pathways.

  10. The association between progression of atherosclerosis and the methylated amino acids asymmetric dimethylarginine and trimethyllysine

    PubMed ID: 23734218

    Associations between methylated amino acids and coronary progression link methionine/SAM pathway products to clinical outcomes.

  11. A new nutraceutical (Livogen PlusÂŽ) improves liver steatosis in adults with non-alcoholic fatty liver disease

    PubMed ID: 35986358

    Product included SAMe (a direct methyl donor) and improved liver fat in NAFLD, indicating influence on methylation‑related biology (multi‑ingredient limit attribution).

  12. Lowering plasma S-Adenosylhomocysteine (SAH) in healthy adults with elevated SAH and normal homocysteine using nutritional supplementation

    PubMed ID: 40883125

    Nutritional product raised SAM:SAH ratio and lowered SAH—direct markers of methylation capacity (L‑methionine was not an ingredient).

  13. Coenzyme Q(10), vitamin E, selenium, and methionine in the treatment of chronic recurrent viral mucocutaneous infections

    PubMed ID: 22079390

    Nutriceutical mixes including L‑methionine accelerated lesion healing and reduced recurrences of HPV/herpes infections, indicating improved tissue repair (multi‑ingredient).

  14. Influence of a methionine synthase (D919G) polymorphism on plasma homocysteine and folate levels and relation to risk of myocardial infarction

    PubMed ID: 11257268

    Methionine synthase gene variant associated with lower homocysteine and higher folate, implicating genetic effects on methylation.

  15. Betaine supplementation decreases post-methionine hyperhomocysteinemia in chronic renal failure

    PubMed ID: 11849459

    Glycine betaine (remethylation substrate) markedly lowered post‑methionine‑load homocysteine (18% lower) in chronic renal failure, directly implicating methionine cycle regulation.

  16. Consumption of wheat aleurone-rich foods increases fasting plasma betaine and modestly decreases fasting homocysteine and LDL-cholesterol in adults

    PubMed ID: 20980654

    Wheat aleurone increased plasma betaine and lowered tHcy — directly impacts remethylation pathway and methyl donors.

  17. l-5-Methyltetrahydrofolate Supplementation Increases Blood Folate Concentrations to a Greater Extent than Folic Acid Supplementation in Malaysian Women

    PubMed ID: 29878267

    l‑5‑MTHF increased folate and lowered homocysteine — improves remethylation capacity and methylation status.

  18. Metabolic Signature of Arsenic Exposure and Metabolism: The Folic Acid and Creatine Trial

    PubMed ID: 40668877

    Arsenic and folic acid interventions changed one‑carbon metabolites (methionine, SAM, betaine) — relevant to methylation.

  19. Effect of L-methionine on hot flashes in postmenopausal women: a randomized controlled trial

    PubMed ID: 19407666

    Direct randomized trial of L‑methionine showed dose‑dependent increases in serum methionine and homocysteine — strong direct evidence that supplemented methionine impacts methylation pathway flux.

  20. One year B and D vitamins supplementation improves metabolic bone markers

    PubMed ID: 23183751

    B‑vitamin therapy lowered homocysteine and SAM/SAH correlations were measured—direct human RCT data linking one‑carbon/methylation metabolites.

  21. Iron sucrose augments homocysteine-induced endothelial dysfunction in normal subjects

    PubMed ID: 16395269

    Oral methionine increased homocysteine and, combined with IV iron, produced acute vascular dysfunction—shows strong acute perturbation of methionine/homocysteine pathway.

  22. S-adenosyl methionine (SAMe) versus escitalopram and placebo in major depression RCT: efficacy and effects of histamine and carnitine as moderators of response

    PubMed ID: 24856557

    SAMe (direct methionine metabolite) showed antidepressant efficacy—functional evidence that methylation metabolites affect brain and mood.

  23. Acute hyperhomocysteinemia impairs endothelium function in subjects with type 2 diabetes mellitus

    PubMed ID: 20200816

    Oral L‑methionine load raised homocysteine and acutely reduced FMD/increased arterial stiffness—clear human evidence methionine affects one‑carbon metabolism and vascular function.

  24. Effect of homocysteine-lowering treatment with folic acid plus vitamin B6 on progression of subclinical atherosclerosis: a randomised, placebo-controlled trial

    PubMed ID: 10683000

    Large randomized folate+B6 trial markedly lowered fasting and post‑load homocysteine—supports modulation of methionine‑cycle methylation by vitamins.

  25. Genomic DNA methylation decreases in response to moderate folate depletion in elderly women

    PubMed ID: 11010943

    Moderate folate depletion reduced genomic DNA methylation (SAM‑dependent) in elderly women—evidence linking folate/methionine cycle to methylation.

  26. Randomized trial of methylcobalamin and folate effects on homocysteine in hemodialysis patients

    PubMed ID: 12021520

    Folic acid normalized elevated homocysteine in dialysis patients — supports remethylation of homocysteine to methionine (methylation cycle).

  27. Efficacy of methylcobalamin on lowering total homocysteine plasma concentrations in haemodialysis patients receiving high-dose folic acid supplementation

    PubMed ID: 11981084

    Methylcobalamin + folic acid produced substantial homocysteine lowering — strong evidence for remethylation pathway modulation.

  28. Changes in basal and postmethionine load concentrations of total homocysteine and cystathionine after B vitamin intervention

    PubMed ID: 15321804

    Folic acid + B12 strongly reduced fasting and post‑load homocysteine in coronary patients — robust effect on methylation pathway.

  29. Effect of nitrous oxide on plasma homocysteine and folate in patients undergoing major surgery

    PubMed ID: 18400808

    Nitrous oxide raises homocysteine by inhibiting methionine synthase — demonstrates vulnerability of methylation processes.

  30. Concentrations of unmetabolized folic acid and primary folate forms in plasma after folic acid treatment in older adults

    PubMed ID: 20727555

    High‑dose folic acid in elderly doubled folate species and halved homocysteine — powerful effect on one‑carbon/methylation processes.

  31. MTHFR C677T and MTR A2756G polymorphisms and the homocysteine lowering efficacy of different doses of folic acid in hypertensive Chinese adults

    PubMed ID: 22230384

    Dose‑dependent homocysteine lowering with folic acid and genotype effects — strong evidence for folate role in remethylation.

  32. Genotypes of the MTHFR C677T and MTRR A66G genes act independently to reduce migraine disability in response to vitamin supplementation

    PubMed ID: 22926161

    B‑vitamin supplementation lowered homocysteine and improved migraine in genotypes — methylation‑linked clinical benefit.

  33. Folic acid supplementation does not reduce intracellular homocysteine, and may disturb intracellular one-carbon metabolism

    PubMed ID: 23740686

    Plasma homocysteine decreased with 500 µg folic acid — shows plasma methylation response (PBMC unchanged).

  34. Effect of folic acid supplementation on plasma homocysteine in obese children: a randomized, double-blind, placebo-controlled trial

    PubMed ID: 25391194

    5 mg folic acid reduced homocysteine in obese children (RCT) — supports remethylation capacity improvement.

  35. Effects of folic acid supplementation on cognitive function and Aβ-related biomarkers in mild cognitive impairment: a randomized controlled trial

    PubMed ID: 29255930

    Folate increased SAM and SAM/SAH ratio and DNMT expression while lowering SAH/homocysteine—clear one‑carbon/methylation pathway effects relevant to methionine cycle.

  36. Dietary Intervention Modifies DNA Methylation Age Assessed by the Epigenetic Clock

    PubMed ID: 30350398

    Folate+B12 changed genome‑wide methylation and reduced epigenetic age in a genotype/sex subgroup—direct epigenetic/methylation evidence.

  37. Treatment of AIDS-associated myelopathy with L-methionine: a placebo-controlled study

    PubMed ID: 15477550

    L‑methionine increased CSF SAM in some subjects—direct evidence methionine can augment methyl‑donor (SAM) pools in CNS, though clinical benefit lacking.

  38. Assessment of pre- and post-methionine load homocysteine for prediction of recurrent stroke and coronary artery disease in the Vitamin Intervention for Stroke Prevention Trial

    PubMed ID: 18166191

    Fasting and post‑methionine homocysteine levels predict vascular events—homocysteine is a central marker of one‑carbon/methylation cycle status.

  39. Bioavailability of S-adenosyl methionine and impact on response in a randomized, double-blind, placebo-controlled trial in major depressive disorder

    PubMed ID: 22687580

    SAMe supplementation (a direct methyl donor derived from Met) caused large rises in plasma SAMe and SAH, directly implicating Met-related methylation biochemistry.

  40. The effect of hyperhomocysteinemia on aortic distensibility in healthy individuals

    PubMed ID: 23434109

    Acute methionine loading raised homocysteine and altered cardiovascular function, showing impact on methylation-related metabolite levels.

  41. Effects of feed grade L-methionine on intestinal redox status, intestinal development, and growth performance of young chickens compared with conventional DL-methionine

    PubMed ID: 26115284

    Increased GSH and reduced protein carbonylation indicate enhanced cellular antioxidant protection and repair capacity.

  42. Randomized, Placebo-Controlled Trial of Methyl B12 for Children with Autism

    PubMed ID: 26889605

    Methyl B12 injections altered plasma methionine, SAH and SAM/SAH ratio and correlated with clinical improvements — relevant to methylation.

  43. Combined Vitamin B-12 and Balanced Protein-Energy Supplementation Affect Homocysteine Remethylation in the Methionine Cycle in Pregnant South Indian Women of Low Vitamin B-12 Status

    PubMed ID: 28446631

    Human trial showed vitamin B12 increased remethylation of homocysteine to methionine (one‑carbon cycle), directly impacting methylation processes.

  44. Double-blind placebo-controlled multicenter phase II trial to evaluate D-methionine in preventing/reducing oral mucositis induced by radiation and chemotherapy for head and neck cancer

    PubMed ID: 29473247

    D‑methionine reduced mucosal injury during chemoradiotherapy — supports tissue protection/repair.

  45. Effects of S-adenosyl-L-Methionine Combined with Ursodesoxycholic Acid on Serum Endotoxin, MMP-9 and IL-18 in Neonates with Cholestasis

    PubMed ID: 34794285

    S‑adenosyl‑L‑methionine (SAMe) is a direct methyl donor; trial showed clinical benefit in cholestasis when added to UDCA.

  46. Effect of adjunctive L-methylfolate 15 mg among inadequate responders to SSRIs in depressed patients who were stratified by biomarker levels and genotype: results from a randomized clinical trial

    PubMed ID: 24813065

    L‑methylfolate improved depression in certain genotypes — supports one‑carbon pathway involvement in brain/methylation.

  47. Effect of Methylfolate, Pyridoxal-5'-Phosphate, and Methylcobalamin (Soloways(TM)) Supplementation on Homocysteine and Low-Density Lipoprotein Cholesterol Levels in Patients with Methylenetetrahydrofolate Reductase, Methionine Synthase, and Methionine Synthase Reductase Polymorphisms: A Randomized Controlled Trial

    PubMed ID: 38892484

    Methylfolate + B‑vitamins markedly lowered homocysteine — strong evidence of modifying one‑carbon/methylation pathways linked to methionine cycle.

  48. A Phase II Randomized, Controlled Trial of S-Adenosylmethionine in Reducing Serum Îą-Fetoprotein in Patients with Hepatitis C Cirrhosis and Elevated AFP

    PubMed ID: 26130251

    Oral SAMe (direct methyl donor derived from methionine) raised SAMe/SAH ratio in cirrhosis patients — direct biochemical evidence of enhanced methylation capacity (SAMe not L‑methionine but closely related metabolite).

  49. Role of sulphydryl-containing agents in the management of venous (varicose) ulceration. A new approach

    PubMed ID: 1486710

    Sulphydryl agents (including methionine derivative) substantially accelerated healing of venous leg ulcers — direct tissue repair evidence.

  50. Double-blind, placebo-controlled study of S-adenosyl-L-methionine in depressed postmenopausal women

    PubMed ID: 8441793

    SAMe supplementation improved depressive symptoms — clinical effect tied to methylation pathways.

  51. Efficacy and tolerability of oral and intramuscular S-adenosyl-L-methionine 1,4-butanedisulfonate (SAMe) in the treatment of major depression: comparison with imipramine in 2 multicenter studies

    PubMed ID: 12418499

    SAMe trials (clinical antidepressant effects) support functional outcomes of augmenting methyl donor pools derived from methionine metabolism.

  52. Plasma homocysteine and S-adenosylmethionine in erythrocytes as determinants of carotid intima-media thickness: different effects in diabetic and non-diabetic individuals. The Hoorn Study

    PubMed ID: 12921985

    Study links erythrocyte SAM and homocysteine to carotid IMT, directly implicating SAM-related methylation status in vascular outcomes.

  53. Elevated serum S-adenosylhomocysteine in cobalamin-deficient elderly and response to treatment

    PubMed ID: 17158426

    Cobalamin-deficient elderly had high SAH and B12 therapy lowered SAH/MMA/homocysteine—direct evidence about one‑carbon/methylation metabolite dynamics.

  54. Leukocyte DNA damage and wound infection after nitrous oxide administration: a randomized controlled trial

    PubMed ID: 23549382

    Nitrous oxide inactivates methionine synthase and increased DNA damage—strong mechanistic evidence that methionine cycle/methylation is critical and that disruption harms methylation processes.

  55. A double-blind, randomized, placebo-controlled clinical trial of S-adenosyl-L-methionine (SAMe) versus escitalopram in major depressive disorder

    PubMed ID: 24500245

    SAMe (a downstream methyl donor derived from methionine) was used as an antidepressant in an RCT—clinical evidence that methylation‑related therapy can have CNS effects.

  56. Is S-Adenosyl Methionine (SAMe) for Depression Only Effective in Males? A Re-Analysis of Data from a Randomized Clinical Trial

    PubMed ID: 26011569

    Post‑hoc finding of male‑specific SAMe antidepressant effect supports clinical relevance of methylation pathway manipulations (indirect evidence).

  57. Adjunctive S-adenosylmethionine (SAMe) in treating non-remittent major depressive disorder: An 8-week double-blind, randomized, controlled trial<sup/>

    PubMed ID: 30115553

    SAMe augmentation trials test a direct methyl donor (downstream of methionine) relevant to methylation biology even if clinical results were negative.

  58. An augmentation study of MSI-195 (S-adenosylmethionine) in Major Depressive Disorder

    PubMed ID: 30368163

    Large SAMe (MSI‑195) trial provides direct evidence about modulation of methylation‑dependent clinical pathways.

  59. Associations of methyl donor and methylation inhibitor levels during anti-oxidant therapy in heart failure

    PubMed ID: 33595776

    Direct measurement of SAM and SAH in response to allopurinol shows methionine‑linked methylation pool is modifiable and clinically measurable.

  60. SAFETY AND EFFICACY OF THE COMPLEX DEPRILIUMÂŽ IN REDUCING SUBCLINICAL SYMPTOMS OF DEPRESSION IN PATIENTS WITH CHRONIC NON-COMMUNICABLE DISEASES: DOUBLE-BLIND RANDOMIZED CONTROLLED STUDY

    PubMed ID: 36883502

    SAMe (a direct methyl donor derived from methionine) was included in an intervention that produced clinical benefits; this supports involvement of methylation pathways though product is multi‑ingredient.

  61. S-adenosyl-L-methionine treatment for alcoholic liver disease: a double-blinded, randomized, placebo-controlled trial

    PubMed ID: 22044287

    Oral SAM increased serum SAM levels, directly reflecting one‑carbon/methylation capacity (though clinical liver benefit was not shown).

  62. Betaine as a determinant of postmethionine load total plasma homocysteine before and after B-vitamin supplementation

    PubMed ID: 14699020

    Betaine strongly predicted smaller homocysteine rises after methionine load → directly informs remethylation to methionine (one‑carbon cycle).

  63. Betaine concentration as a determinant of fasting total homocysteine concentrations and the effect of folic acid supplementation on betaine concentrations

    PubMed ID: 15941890

    Folic acid supplementation increased plasma betaine and lowered homocysteine — supports pathways that remethylate homocysteine to methionine.

Liver support (22)
  1. S-adenosylmethionine in alcoholic liver cirrhosis: a randomized, placebo-controlled, double-blind, multicenter clinical trial

    PubMed ID: 10406187

    Two‑year SAMe reduced death/transplantation in alcoholic cirrhosis (significant in less severe strata) — clinically meaningful liver outcome.

  2. Efficacy and safety of intravenous stronger neo-minophagen C and S-adenosyl-L-methionine in treatment of pregnant woman with chronic hepatitis B: a pilot study

    PubMed ID: 20671623

    SAMe improved liver enzymes in pregnant women with chronic hepatitis B (less effective than comparator but clearly hepatically active).

  3. Ursodeoxycholic acid and S-adenosylmethionine in the treatment of intrahepatic cholestasis of pregnancy: a multi-centered randomized controlled trial

    PubMed ID: 26502869

    SAMe improved symptoms and some liver tests in intrahepatic cholestasis of pregnancy (UDCA was superior for some measures).

  4. Effect of S-adenosyl-L-methionine administration on red blood cell cysteine and glutathione levels in alcoholic patients with and without liver disease

    PubMed ID: 7811344

    Parenteral SAMe corrected erythrocyte glutathione and cysteine in alcohol users → strong methionine‑pathway effect on hepatic redox status.

  5. [Parenteral S-adenosylmethionine compared to placebos in the treatment of alcoholic liver diseases]

    PubMed ID: 8679834

    SAMe improved glutathione, reduced lipid peroxidation and improved lab indices in alcoholic liver disease → clinically relevant liver benefit (SAMe is methionine downstream metabolite).

  6. Quantitative liver function tests improve the prediction of clinical outcomes in chronic hepatitis C: results from the Hepatitis C Antiviral Long-term Treatment Against Cirrhosis Trial

    PubMed ID: 22030902

    Methionine breath test (MBT) predicted liver decompensation → methionine metabolism is a liver function marker.

  7. Hepatic Activity and Transcription of Betaine-Homocysteine Methyltransferase, Methionine Synthase, and Cystathionine Synthase in Periparturient Dairy Cows Are Altered to Different Extents by Supply of Methionine and Choline

    PubMed ID: 27881594

    Rumen‑protected methionine altered hepatic methylation enzyme expression/activity (MAT1A, PEMT, SAHH, CBS), indicating major hepatic one‑carbon effects.

  8. Rumen-protected methionine compared with rumen-protected choline improves immunometabolic status in dairy cows during the peripartal period

    PubMed ID: 27592438

    Methionine supplementation in transition dairy cows increased liver glutathione and improved hepatic antioxidant markers.

  9. [The results of phase III multicenter open randomized controlled study REM-Chol-III-16 in patients with intrahepatic cholestasis syndrome caused by chronic diffuse liver diseases]

    PubMed ID: 36286675

    Remaxol (contains methionine) was non‑inferior to SAMe for improving cholestasis labs in intrahepatic cholestasis patients (multi‑component product).

  10. 5-MTHF enhances the portal pressure reduction achieved with propranolol in patients with cirrhosis: A randomized placebo-controlled trial

    PubMed ID: 37482222

    5‑MTHF reduced homocysteine and improved portal pressure and NO markers in cirrhosis—relates to one‑carbon metabolism and hepatic hemodynamics.

  11. A new nutraceutical (Livogen PlusÂŽ) improves liver steatosis in adults with non-alcoholic fatty liver disease

    PubMed ID: 35986358

    Randomized trial of a SAMe‑containing multi‑ingredient nutraceutical improved liver fat in NAFLD—strongest liver‑related human data in the set (attribution to methionine/SAMe indirect due to multi‑ingredient product).

  12. [A trial of ademetionine in the treatment of intrahepatic biliary stasis viral hepatitis]

    PubMed ID: 10880165

    Ademetionine (SAMe, a downstream methionine metabolite) improved jaundice, LFTs and pruritus in cholestatic viral hepatitis — mechanistically linked to methionine→SAM pathways.

  13. Isocaloric Diets High in Animal or Plant Protein Reduce Liver Fat and Inflammation in Individuals With Type 2 Diabetes

    PubMed ID: 27765690

    High‑protein diets (with higher postprandial methionine on animal protein) produced marked intrahepatic fat loss and improved liver‑related markers (direct diet/methionine relevance).

  14. Quantitative tests of liver function measure hepatic improvement after sustained virological response: results from the HALT-C trial

    PubMed ID: 19053983

    Methionine breath test used as probe of hepatic mitochondrial function in HCV; demonstrates methionine mapping to measurable liver function (direct methodological relevance).

  15. Impact of the Association Between PNPLA3 Genetic Variation and Dietary Intake on the Risk of Significant Fibrosis in Patients With NAFLD

    PubMed ID: 33306506

    Large human observational study found higher dietary methionine intake strongly associated with lower risk of significant fibrosis in NAFLD (robust adjusted associations).

  16. A comparison of two sources of methionine supplemented at different levels on heat shock protein 70 expression and oxidative stress product of Peking ducks subjected to heat stress

    PubMed ID: 28503893

    Dietary methionine altered hepatic oxidative markers and reduced protein carbonylation in ducks, implying hepatic antioxidant benefit.

  17. Effects of S-adenosyl-L-Methionine Combined with Ursodesoxycholic Acid on Serum Endotoxin, MMP-9 and IL-18 in Neonates with Cholestasis

    PubMed ID: 34794285

    S‑adenosyl‑L‑methionine + UDCA improved clinical recovery and inflammatory markers in neonatal cholestasis — strong liver benefit in RCT.

  18. Oral S-adenosylmethionine in the symptomatic treatment of intrahepatic cholestasis. A double-blind, placebo-controlled study

    PubMed ID: 2188871

    Oral SAMe significantly improved cholestasis biochemistry and symptoms (bilirubin, alkaline phosphatase, pruritus, fatigue) vs placebo — strong liver benefit.

  19. S-adenosylmethionine for the treatment of intrahepatic cholestasis of pregnancy. Results of a controlled clinical trial

    PubMed ID: 2083923

    IV SAMe reduced bile acids, bilirubin and itching in intrahepatic cholestasis of pregnancy — objective liver improvements.

  20. [Analysis on therapeutic effect of Western and Chinese drug in treating intrahepatic cholestasis pregnancy]

    PubMed ID: 15143715

    Small randomized comparison in intrahepatic cholestasis of pregnancy: SAMe improved itching and liver biochemistry—direct liver-related clinical evidence for SAMe.

  21. Beneficial effects of S-adenosyl-L-methionine on post-hepatectomy residual liver function: a prospective, randomized, controlled clinical trial

    PubMed ID: 23491928

    RCT: IV SAMe reduced postoperative liver dysfunction markers in cirrhotic patients undergoing resection (benefit strongest in patients with longer ischemia)—direct clinical liver benefit from a methionine product.

  22. Metabolomics as a tool to predict the risk of decompensation or liver-related death in patients with compensated cirrhosis

    PubMed ID: 36811400

    Plasma methionine was one of the metabolites that improved prediction of decompensation/liver‑related death in compensated cirrhosis — associative but relevant to liver outcomes.

Detoxification (20)
  1. Effect of Methylfolate, Pyridoxal-5'-Phosphate, and Methylcobalamin (Soloways(TM)) Supplementation on Homocysteine and Low-Density Lipoprotein Cholesterol Levels in Patients with Methylenetetrahydrofolate Reductase, Methionine Synthase, and Methionine Synthase Reductase Polymorphisms: A Randomized Controlled Trial

    PubMed ID: 38892484

    B‑vitamin/methylfolate lowering homocysteine supports one‑carbon metabolism linked to detoxification and conjugation pathways.

  2. Oral S-adenosylmethionine in the symptomatic treatment of intrahepatic cholestasis. A double-blind, placebo-controlled study

    PubMed ID: 2188871

    Oral SAMe improved cholestasis biochemistry (bilirubin, ALP) and symptoms — supports hepatic detox/function.

  3. S-adenosylmethionine for the treatment of intrahepatic cholestasis of pregnancy. Results of a controlled clinical trial

    PubMed ID: 2083923

    IV SAMe reduced bile acids and bilirubin in cholestasis of pregnancy — evidence for improved hepatic bile detox/clearance.

  4. S-adenosylmethionine in alcoholic liver cirrhosis: a randomized, placebo-controlled, double-blind, multicenter clinical trial

    PubMed ID: 10406187

    Two‑year SAMe lowered death/transplant rates in alcoholic cirrhosis strata — long‑term support of liver function/detox outcomes.

  5. Beneficial effects of S-adenosyl-L-methionine on post-hepatectomy residual liver function: a prospective, randomized, controlled clinical trial

    PubMed ID: 23491928

    IV SAMe improved postoperative liver function parameters in cirrhotic patients undergoing resection—supports hepatic (detox) capacity enhancement in a clinical setting.

  6. Effect of S-adenosyl-L-methionine administration on red blood cell cysteine and glutathione levels in alcoholic patients with and without liver disease

    PubMed ID: 7811344

    SAMe normalized thiol disturbances (glutathione/cysteine) in alcohol users → supports detox (phase II redox) capacity.

  7. [Parenteral S-adenosylmethionine compared to placebos in the treatment of alcoholic liver diseases]

    PubMed ID: 8679834

    SAMe decreased lipid peroxidation and improved glutathione in alcoholic liver disease → supports detox/antioxidant pathways.

  8. Betaine as a determinant of postmethionine load total plasma homocysteine before and after B-vitamin supplementation

    PubMed ID: 14699020

    Betaine predicted smaller homocysteine rises after methionine load → remethylation supports homocysteine clearance/detox balance.

  9. Hepatic Activity and Transcription of Betaine-Homocysteine Methyltransferase, Methionine Synthase, and Cystathionine Synthase in Periparturient Dairy Cows Are Altered to Different Extents by Supply of Methionine and Choline

    PubMed ID: 27881594

    Hepatic changes in transsulfuration enzymes (CBS) suggest enhanced flux toward glutathione and detox pathways.

  10. [The results of phase III multicenter open randomized controlled study REM-Chol-III-16 in patients with intrahepatic cholestasis syndrome caused by chronic diffuse liver diseases]

    PubMed ID: 36286675

    Multi‑component infusion containing methionine performed similarly to SAMe in improving cholestasis labs—relevant to hepatic detox/excretion.

  11. Rumen-protected methionine compared with rumen-protected choline improves immunometabolic status in dairy cows during the peripartal period

    PubMed ID: 27592438

    Increased hepatic glutathione with methionine supports phase II antioxidant detoxification capacity.

  12. A new nutraceutical (Livogen PlusÂŽ) improves liver steatosis in adults with non-alcoholic fatty liver disease

    PubMed ID: 35986358

    SAMe‑containing nutraceutical reduced liver fat in NAFLD patients—suggests improved hepatic metabolic/detox capacity (study multi‑ingredient but SAMe/methionine relevant to detox via glutathione pathways).

  13. [A trial of ademetionine in the treatment of intrahepatic biliary stasis viral hepatitis]

    PubMed ID: 10880165

    SAMe (methionine derivative) improved cholestasis and liver tests, supporting methionine→SAM role in hepatic detox and biliary function.

  14. Betaine supplementation decreases post-methionine hyperhomocysteinemia in chronic renal failure

    PubMed ID: 11849459

    Betaine enhanced remethylation and reduced post‑load homocysteine, supporting metabolic clearance pathways connected to methionine cycle (detox relevance).

  15. Metabolic Signature of Arsenic Exposure and Metabolism: The Folic Acid and Creatine Trial

    PubMed ID: 40668877

    Arsenic exposure and folic acid shifts show methionine/SAM/betaine associations relevant to arsenic methylation/detox capacity.

  16. Effect of homocysteine-lowering treatment with folic acid plus vitamin B6 on progression of subclinical atherosclerosis: a randomised, placebo-controlled trial

    PubMed ID: 10683000

    B‑vitamin regimen greatly reduced homocysteine (a detox/recycling intermediary), supporting homocysteine clearance pathways.

  17. Effect of nitrous oxide on plasma homocysteine and folate in patients undergoing major surgery

    PubMed ID: 18400808

    Nitrous oxide‑induced homocysteine rises linked to complications — shows importance of intact methionine‑dependent detox pathways.

  18. Effects of feed grade L-methionine on intestinal redox status, intestinal development, and growth performance of young chickens compared with conventional DL-methionine

    PubMed ID: 26115284

    L‑Met markedly increased glutathione (key detox molecule) and total antioxidant capacity in broiler intestine.

  19. A comparison of two sources of methionine supplemented at different levels on heat shock protein 70 expression and oxidative stress product of Peking ducks subjected to heat stress

    PubMed ID: 28503893

    Methionine modulated hepatic oxidative markers and HSP70 expression under stress, consistent with improved detox/stress handling.

  20. Effects of S-adenosyl-L-Methionine Combined with Ursodesoxycholic Acid on Serum Endotoxin, MMP-9 and IL-18 in Neonates with Cholestasis

    PubMed ID: 34794285

    SAMe + UDCA improved cholestasis and reduced endotoxin/inflammatory markers — supports hepatic detox/clearance.

Metabolism (14)
  1. Dietary sulfur amino acid restriction in humans with overweight and obesity: Evidence of an altered plasma and urine sulfurome, and a novel metabolic signature that correlates with loss of fat mass and adipose tissue gene expression

    PubMed ID: 38776754

    Direct human SAAR produced major changes in sulfur metabolites and a metabolic signature tied to fat loss — strong relevance to methionine‑linked metabolism.

  2. Dietary sulfur amino acid restriction in humans with overweight and obesity: a translational randomized controlled trial

    PubMed ID: 38195568

    Double‑blind RCT of sulfur amino‑acid restriction showed significant weight loss, lower leptin and marked biochemical changes — strong metabolic effect related to methionine intake.

  3. Efficacy and safety of methionine aminopeptidase 2 inhibition in type 2 diabetes: a randomised, placebo-controlled clinical trial

    PubMed ID: 29992370

    Beloranib in obese T2D gave large weight and HbA1c improvements; strong metabolic signal via an enzyme linked to methionine processing.

  4. Effects of MetAP2 inhibition on hyperphagia and body weight in Prader-Willi syndrome: A randomized, double-blind, placebo-controlled trial

    PubMed ID: 28556449

    Beloranib (MetAP2 inhibitor) produced large weight/fat mass and metabolic benefits — mechanistically tied to methionine processing (MetAP2) though not L‑methionine supplementation.

  5. [A controlled study of AO-90, a methionine-free intravenous amino acid solution, in combination with 5-fluorouracil and mitomycin C in advanced gastric cancer patients (internal medicine group evaluation)]

    PubMed ID: 7755384

    Confirmatory trial showing methionine restriction changed clinical response rates — metabolic intervention evidence.

  6. [A controlled study of AO-90, a methionine-free intravenous amino acid solution, in combination with 5-fluorouracil and mitomycin C in advanced gastric cancer patients (surgery group evaluation)]

    PubMed ID: 7755383

    Methionine‑free TPN altered tumor response to chemotherapy — strong metabolic effect of methionine manipulation.

  7. Effects of feed grade L-methionine on intestinal redox status, intestinal development, and growth performance of young chickens compared with conventional DL-methionine

    PubMed ID: 26115284

    L‑Met improved growth performance (ADG, G:F) and intestinal redox status in broilers, demonstrating metabolic improvements.

  8. Differential effects of protein intake versus intake of a defined oligopeptide on FGF-21 in obese human subjects in vivo

    PubMed ID: 32600859

    In obese humans, higher dietary methionine/protein intake correlated with lower FGF‑21 (metabolic regulator)—cohort and intervention signals.

  9. Efficacy of DL-methionine hydroxy analog free acid and DL-methionine as methionine sources for pigs

    PubMed ID: 16361496

    Weanling pig studies: dl‑methionine improved growth and nitrogen retention—translational evidence of methionine supporting metabolic/anabolic processes.

  10. Ascending dose-controlled trial of beloranib, a novel obesity treatment for safety, tolerability, and weight loss in obese women

    PubMed ID: 23512440

    MetAP2 inhibitor (acts on methionine processing) produced rapid weight loss and lipid improvements; mechanistic link to methionine biology and metabolic outcomes.

  11. Isocaloric Diets High in Animal or Plant Protein Reduce Liver Fat and Inflammation in Individuals With Type 2 Diabetes

    PubMed ID: 27765690

    6‑week high‑protein diets raised postprandial methionine and produced large reductions in liver fat, FGF21 and inflammation (direct diet/methionine relevance).

  12. Better postpartal performance in dairy cows supplemented with rumen-protected methionine compared with choline during the peripartal period

    PubMed ID: 27638261

    Rumen‑protected methionine increased feed intake, milk yield and milk protein—clear metabolic effects in dairy cows.

  13. Are dietary amino acids prospectively predicts changes in serum lipid profile?

    PubMed ID: 31235103

    Large prospective cohort: dietary methionine intake predicted changes in triglycerides and cholesterol — strong metabolic relevance.

  14. Evaluation of the efficacy of an antioxidant combination for the modulation of metabolic, endocrine, and clinical parameters in patients with polycystic ovary syndrome

    PubMed ID: 37356455

    PCOS antioxidant formula containing SAMe improved HOMA‑IR; metabolic benefit present but multi‑ingredient confounding.

Muscle growth (13)
  1. Better postpartal performance in dairy cows supplemented with rumen-protected methionine compared with choline during the peripartal period

    PubMed ID: 27638261

    Supplemental methionine increased milk protein concentration and yield in dairy cows (clear protein‑anabolic effect in animal lactation).

  2. Effects of feed grade L-methionine on intestinal redox status, intestinal development, and growth performance of young chickens compared with conventional DL-methionine

    PubMed ID: 26115284

    Direct large broiler trial: L‑Met > DL‑Met for ADG and gain:feed and improved intestinal/redox markers relevant to protein accretion.

  3. Methionine improves the performance and breast muscle growth of broilers with lower hatching weight by altering the expression of genes associated with the insulin-like growth factor-I signalling pathway

    PubMed ID: 23919886

    Boosting dietary Met improved growth and breast-muscle development in low-weight broilers with IGF‑I pathway changes—strong protein-building evidence in that context.

  4. Methionine requirement of the enterally fed term infant in the first month of life in the presence of cysteine

    PubMed ID: 22492372

    Measured minimal methionine requirement in term infants (mg/kg/d) demonstrating Met is essential for protein synthesis in humans.

  5. Effects of diets with different protein and DL-methionine levels on the growth performance and N-balance of growing minks

    PubMed ID: 21635571

    DL‑Met supplementation improved growth and N retention in mink, indicating support for protein accrual and efficient N use.

  6. Effect of dietary methionine on growth performance and insulin-like growth factor-I mRNA expression of growing meat rabbits

    PubMed ID: 20487098

    Dietary Met dose-dependently increased rabbit ADG and IGF‑I expression, showing role in growth/protein accretion.

  7. Effects of dietary supplementation of methionine and lysine on milk production and nitrogen utilization in dairy cows

    PubMed ID: 20655436

    Met supplementation increased milk yield and improved milk composition, reflecting improved protein/nitrogen utilization.

  8. Effects of providing two forms of supplemental methionine to periparturient Holstein dairy cows on feed intake and lactational performance

    PubMed ID: 19762834

    Two supplemental Met forms increased plasma Met and milk protein content in dairy cows; supports role in protein synthesis.

  9. Evidence of a different dose response in turkeys when fed 2-hydroxy-4(methylthio) butanoic acid versus DL-methionine

    PubMed ID: 17297164

    Different Met sources produced rapid differences in plasma Met and growth in turkeys, showing impact on protein accretion kinetics.

  10. Determining the methionine activity of Mintrex organic trace minerals in broiler chicks by using radiolabel tracing or growth assay

    PubMed ID: 17435021

    HMTBA provided methionine activity and was incorporated into protein equally as free HMTBA; clear evidence of Met supporting protein synthesis (avian model).

  11. Efficacy of DL-methionine hydroxy analog free acid and DL-methionine as methionine sources for pigs

    PubMed ID: 16361496

    Weanling pig feeding trials: dl‑methionine improved growth and nitrogen retention—translational support for methionine's role in protein accretion.

  12. Estimation of the true ileal digestible lysine and sulfur amino acid requirement and comparison of the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid and DL-methionine in eleven- to twenty-six-kilogram nursery pigs

    PubMed ID: 16775054

    Large nursery-pig experiments showing digestible SAA (methionine activity) improved growth and feed efficiency—strong animal evidence for protein-building role.

  13. Effect of essential amino acid supplementation and aerobic exercise on insulin sensitivity in healthy older adults: A randomized clinical trial

    PubMed ID: 31307843

    22‑week essential amino acid supplementation (which includes methionine) trial directly targeted amino‑acid provision relevant to protein anabolism in older adults.

Antioxidant (11)
  1. Long-term supplementation with selenate and selenomethionine: urinary excretion by New Zealand women

    PubMed ID: 9155505

    Selenomethionine supplementation raised plasma selenium substantially over weeks — selenium is a cofactor for antioxidant selenoenzymes (direct pharmacokinetic support).

  2. [Parenteral S-adenosylmethionine compared to placebos in the treatment of alcoholic liver diseases]

    PubMed ID: 8679834

    SAMe increased glutathione and reduced lipid peroxidation in alcoholic liver disease → supports antioxidant production via methionine cycle.

  3. Hepatic Activity and Transcription of Betaine-Homocysteine Methyltransferase, Methionine Synthase, and Cystathionine Synthase in Periparturient Dairy Cows Are Altered to Different Extents by Supply of Methionine and Choline

    PubMed ID: 27881594

    Hepatic upregulation of transsulfuration enzymes (CBS) and SAHH suggests increased flux to cysteine/glutathione with methionine.

  4. Rumen-protected methionine compared with rumen-protected choline improves immunometabolic status in dairy cows during the peripartal period

    PubMed ID: 27592438

    Methionine supplementation increased hepatic total and reduced glutathione and improved several antioxidant markers in cows.

  5. Effect of diets with different inclusion levels of distillers dried grain with solubles combined with lysine and methionine supplementation on the lipid peroxidation and glutathione status of chickens

    PubMed ID: 21665573

    Adding Met (with other diet changes) increased liver reduced glutathione and GSHPx activity in broilers—direct evidence Met provisioning supports GSH-related antioxidant capacity.

  6. Effects of feed grade L-methionine on intestinal redox status, intestinal development, and growth performance of young chickens compared with conventional DL-methionine

    PubMed ID: 26115284

    L‑Met substantially increased glutathione and total antioxidant capacity in broiler intestine — direct evidence of antioxidant boosting.

  7. A comparison of two sources of methionine supplemented at different levels on heat shock protein 70 expression and oxidative stress product of Peking ducks subjected to heat stress

    PubMed ID: 28503893

    Dietary methionine modulated oxidative stress markers and HSP70 expression under heat stress in ducks.

  8. Effect of S-adenosyl-L-methionine administration on red blood cell cysteine and glutathione levels in alcoholic patients with and without liver disease

    PubMed ID: 7811344

    Parenteral SAMe restored erythrocyte glutathione in alcohol users → direct evidence of boosting glutathione (major antioxidant) via methionine‑pathway metabolite.

  9. Plasma glutathione of HIV⁺ patients responded positively and differently to dietary supplementation with cysteine or glutamine

    PubMed ID: 22261571

    NAC/glutamine raised glutathione and sulfur amino acids in HIV patients — clear support for antioxidant capacity (related sulfur biochemistry).

  10. Long-term supplementation with selenate and selenomethionine: selenium and glutathione peroxidase (EC 1.11.1.9) in blood components of New Zealand women

    PubMed ID: 8490010

    Selenomethionine supplementation raised blood selenium and GPx activity — supports antioxidant selenoenzyme capacity.

  11. Effects of vitamin C, vitamin E, zinc gluconate, and selenomethionine supplementation on muscle function and oxidative stress biomarkers in patients with facioscapulohumeral dystrophy: a double-blind randomized controlled clinical trial

    PubMed ID: 25246239

    Combination supplement including selenomethionine reduced oxidative‑stress markers and improved muscle performance in FSHD patients—antioxidant biomarker improvement consistent with selenium‑methionine effects.

Healthy aging (9)
  1. Dietary sulfur amino acid restriction in humans with overweight and obesity: Evidence of an altered plasma and urine sulfurome, and a novel metabolic signature that correlates with loss of fat mass and adipose tissue gene expression

    PubMed ID: 38776754

    Human methionine/sulfur‑AA restriction produced metabolic changes linked to fat loss and pathways implicated in longevity (mechanistic relevance to methionine biology).

  2. Dietary sulfur amino acid restriction in humans with overweight and obesity: a translational randomized controlled trial

    PubMed ID: 38195568

    Randomized SAAR in humans produced weight/leptin changes and metabolic adaptations that are consistent with mechanisms proposed for methionine‑restriction benefits on aging.

  3. The Association of the Essential Amino Acids Lysine, Methionine, and Threonine with Clinical Outcomes in Patients at Nutritional Risk: Secondary Analysis of a Randomized Clinical Trial

    PubMed ID: 39203745

    Low blood methionine at admission associated with higher short‑term mortality/functional decline — observational link to worse aging outcomes.

  4. Assessment of pre- and post-methionine load homocysteine for prediction of recurrent stroke and coronary artery disease in the Vitamin Intervention for Stroke Prevention Trial

    PubMed ID: 18166191

    Large cohort: fasting homocysteine (methionine metabolism marker) predicted recurrent stroke/CAD risk, linking methionine metabolism to vascular ageing risk.

  5. Dietary Intervention Modifies DNA Methylation Age Assessed by the Epigenetic Clock

    PubMed ID: 30350398

    Folate+B12 lowered epigenetic (DNA methylation) age in a subgroup—direct aging‑relevant epigenetic finding.

  6. Concentrations of unmetabolized folic acid and primary folate forms in plasma after folic acid treatment in older adults

    PubMed ID: 20727555

    High‑dose folic acid halved homocysteine in elderly — substantial biochemical effect tied to age‑related risk markers.

  7. Effect of nitrous oxide on plasma homocysteine and folate in patients undergoing major surgery

    PubMed ID: 18400808

    Postop hyperhomocysteinaemia linked to more major complications — strong link between Hcy (methionine pathway) and adverse outcomes.

  8. Effect of homocysteine-lowering treatment with folic acid plus vitamin B6 on progression of subclinical atherosclerosis: a randomised, placebo-controlled trial

    PubMed ID: 10683000

    Large B‑vitamin trial lowered homocysteine and reduced an ischemia surrogate—indirectly relevant to aging/vascular health.

  9. Traditional Korean diet high in one-carbon nutrients increases global DNA methylation: implication for epigenetic diet

    PubMed ID: 38867083

    Diet rich in one‑carbon nutrients increased global DNA methylation (mechanism linked to aging epigenetics).

Brain health (11)
  1. S-adenosyl methionine (SAMe) augmentation of serotonin reuptake inhibitors for antidepressant nonresponders with major depressive disorder: a double-blind, randomized clinical trial

    PubMed ID: 20595412

    Adjunctive SAMe improved depressive symptoms (clinical CNS outcome), supporting brain health relevance.

  2. A Phase II Randomized Clinical Trial of a Nutritional Formulation for Cognition and Mood in Alzheimer's Disease

    PubMed ID: 25589719

    Phase II Alzheimer’s trial of multi‑nutrient containing SAMe showed improved cognitive/dementia scores vs placebo at 3 months.

  3. A vitamin/nutriceutical formulation improves memory and cognitive performance in community-dwelling adults without dementia

    PubMed ID: 20191258

    Multi‑nutrient including SAMe improved memory and executive function in non‑demented adults—clinical cognitive benefit relevant to brain health.

  4. Effects of S-adenosylmethionine augmentation of serotonin-reuptake inhibitor antidepressants on cognitive symptoms of major depressive disorder

    PubMed ID: 21911258

    Adjunctive SAMe improved some memory/recall measures in depressed patients—clinical cognitive/brain‑related benefit in a patient group.

  5. Effects of S-adenosylmethionine augmentation of serotonin-reuptake inhibitor antidepressants on cognitive symptoms of major depressive disorder

    PubMed ID: 21665441

    Duplicate/secondary report of the adjunctive SAMe trial showing modest recall benefit—same rationale.

  6. Genotypes of the MTHFR C677T and MTRR A66G genes act independently to reduce migraine disability in response to vitamin supplementation

    PubMed ID: 22926161

    B‑vitamin supplementation reduced migraine severity in genotype‑defined subgroups — neurological benefit linked to homocysteine lowering.

  7. Effects of folic acid supplementation on cognitive function and Aβ-related biomarkers in mild cognitive impairment: a randomized controlled trial

    PubMed ID: 29255930

    Folate lowered homocysteine, raised SAM/SAM:SAH and improved cognition—directly links one‑carbon/methylation to cognitive outcomes.

  8. Double-blind, placebo-controlled study of S-adenosyl-L-methionine in depressed postmenopausal women

    PubMed ID: 8441793

    SAMe provided antidepressant benefit — relevant to brain/neuropsychiatric health.

  9. Efficacy and tolerability of oral and intramuscular S-adenosyl-L-methionine 1,4-butanedisulfonate (SAMe) in the treatment of major depression: comparison with imipramine in 2 multicenter studies

    PubMed ID: 12418499

    Large SAMe antidepressant RCTs show clinical CNS effects; SAMe is a methionine metabolite with central activity.

  10. Eggs early in complementary feeding increase choline pathway biomarkers and DHA: a randomized controlled trial in Ecuador

    PubMed ID: 29092879

    One‑egg/day in infants raised plasma methionine and DHA—both relevant to neurodevelopment and brain health.

  11. Genomic DNA methylation decreases in response to moderate folate depletion in elderly women

    PubMed ID: 11010943

    Folate depletion reduced genomic DNA methylation (SAM‑dependent) in elderly women—relevant to brain epigenetic health via methionine cycle.

Mood balance (11)
  1. SAFETY AND EFFICACY OF THE COMPLEX DEPRILIUMÂŽ IN REDUCING SUBCLINICAL SYMPTOMS OF DEPRESSION IN PATIENTS WITH CHRONIC NON-COMMUNICABLE DISEASES: DOUBLE-BLIND RANDOMIZED CONTROLLED STUDY

    PubMed ID: 36883502

    Randomized trial of a SAMe‑containing complex produced clinically meaningful improvements in depressive symptoms (HAM‑D) versus placebo, but other active ingredients confound attribution to methionine per se.

  2. S-adenosyl methionine (SAMe) versus escitalopram and placebo in major depression RCT: efficacy and effects of histamine and carnitine as moderators of response

    PubMed ID: 24856557

    SAMe (a direct methionine metabolite) produced greater antidepressant benefit vs placebo in adults with major depression—strong indirect evidence linking methionine→SAMe to mood.

  3. Is S-Adenosyl Methionine (SAMe) for Depression Only Effective in Males? A Re-Analysis of Data from a Randomized Clinical Trial

    PubMed ID: 26011569

    Post‑hoc reanalysis showed a robust antidepressant effect of SAMe in men (large effect size) — notable but requires replication (indirectly relevant to methionine via SAMe).

  4. Efficacy of a food supplement based on S-adenosyl methionine and probiotic strains in subjects with subthreshold depression and mild-to-moderate depression: A monocentric, randomized, cross-over, double-blind, placebo-controlled clinical trial

    PubMed ID: 36411659

    3‑month SAMe+probiotic trial reduced depression scores — reasonably strong signal for SAMe (downstream of methionine) on mood.

  5. Effects of S-adenosylmethionine augmentation of serotonin-reuptake inhibitor antidepressants on cognitive symptoms of major depressive disorder

    PubMed ID: 21665441

    Secondary/duplicate report of the same adjunctive SAMe trial showing modest recall improvement—same rationale as above.

  6. A double-blind, randomized, placebo-controlled clinical trial of S-adenosyl-L-methionine (SAMe) versus escitalopram in major depressive disorder

    PubMed ID: 24500245

    Large RCT of SAMe vs escitalopram found similar improvements but no clear separation from placebo—some signal for antidepressant/mood effect though endpoint was negative.

  7. Effects of S-adenosylmethionine augmentation of serotonin-reuptake inhibitor antidepressants on cognitive symptoms of major depressive disorder

    PubMed ID: 21911258

    Adjunctive SAMe in SSRI nonresponders modestly improved memory recall and some cognitive symptoms in depressed patients—supports mood/cognitive symptom improvement when added to antidepressants.

  8. S-adenosyl methionine (SAMe) augmentation of serotonin reuptake inhibitors for antidepressant nonresponders with major depressive disorder: a double-blind, randomized clinical trial

    PubMed ID: 20595412

    Randomized double-blind adjunctive SAMe trial in SRI nonresponders produced substantially higher response/remission rates—robust adjunctive mood benefit.

  9. Efficacy and tolerability of oral and intramuscular S-adenosyl-L-methionine 1,4-butanedisulfonate (SAMe) in the treatment of major depression: comparison with imipramine in 2 multicenter studies

    PubMed ID: 12418499

    Large multicenter RCTs found SAMe antidepressant efficacy comparable to imipramine with better tolerability—strong clinical support for mood benefit (SAMe = methionine-derived).

  10. Double-blind, placebo-controlled study of S-adenosyl-L-methionine in depressed postmenopausal women

    PubMed ID: 8441793

    Double‑blind RCT: oral SAMe significantly improved depressive symptoms in postmenopausal women with early effect — strong clinical evidence.

  11. Bioavailability of S-adenosyl methionine and impact on response in a randomized, double-blind, placebo-controlled trial in major depressive disorder

    PubMed ID: 22687580

    Adjunctive SAMe in depressed patients produced large biochemical increases in SAMe/SAH; SAMe is an established antidepressant adjunct (biochemical support present).

Immune support (11)
  1. The effect of levothyroxine and selenomethionine on lymphocyte and monocyte cytokine release in women with Hashimoto's thyroiditis

    PubMed ID: 21508145

    Selenomethionine reduced lymphocyte cytokine release in Hashimoto's—direct immune‑modulating effect (selenium bound to methionine).

  2. l-selenomethionine supplementation in children and adolescents with autoimmune thyroiditis: A randomized double-blind placebo-controlled clinical trial

    PubMed ID: 30306604

    Seleno‑L‑methionine lowered anti‑thyroglobulin antibodies in autoimmune thyroiditis — direct immunomodulatory signal from a methionine derivative.

  3. Effects of a six month treatment with selenomethionine in patients with autoimmune thyroiditis

    PubMed ID: 12656658

    Selenomethionine markedly lowered thyroid autoantibodies in autoimmune thyroiditis — clear immunomodulatory effect.

  4. Probiotic effects on immunity and microbiome in HIV-1 discordant patients

    PubMed ID: 36569851

    Synbiotic reduced microbial L‑methionine biosynthesis and modestly improved immune/inflammation markers in HIV patients.

  5. Double-blind placebo-controlled multicenter phase II trial to evaluate D-methionine in preventing/reducing oral mucositis induced by radiation and chemotherapy for head and neck cancer

    PubMed ID: 29473247

    D‑methionine reduced chemoradiotherapy mucositis and pain — clinically meaningful mucosal/host protection during cytotoxic therapy.

  6. Effects of zinc-methionine on growth performance, intestinal flora and immune function in pigeon squabs

    PubMed ID: 24784175

    Zinc‑methionine in pigeon squabs increased immune organ weights and antibody titers, clearly enhancing immune indices.

  7. Pathology of bursae of Fabricius in methionine-deficient broiler chickens

    PubMed ID: 23486195

    Methionine‑deficient broilers had markedly smaller bursa and increased bursal apoptosis, showing Met is important for primary immune organ integrity.

  8. [Prevention of reinfection by L-methionine in patients with recurrent urinary tract infection]

    PubMed ID: 9446004

    Direct human series where long‑term oral L‑methionine prevented recurrent acute UTIs and reduced bacterial adherence—strongest direct L‑methionine clinical effect in dataset.

  9. Coenzyme Q(10), vitamin E, selenium, and methionine in the treatment of chronic recurrent viral mucocutaneous infections

    PubMed ID: 22079390

    Trials with a formula containing L‑methionine reduced viral lesion relapses and increased antiviral markers—supports immune/antiviral resilience (confounded by other ingredients).

  10. Marginal deficiencies of dietary arginine and methionine could suppress growth performance and immunological responses in broiler chickens

    PubMed ID: 28447340

    In broiler chickens, correcting methionine deficiency improved antibody responses—supports an immune role (animal model).

  11. Rumen-protected methionine compared with rumen-protected choline improves immunometabolic status in dairy cows during the peripartal period

    PubMed ID: 27592438

    Rumen‑protected methionine increased liver glutathione and enhanced neutrophil phagocytosis/oxidative burst in transition cows.

Nutrition source (10)
  1. Sulfhydryl-containing agents in the treatment of gastric bleeding induced by nonsteroidal anti-inflammatory drugs

    PubMed ID: 8443719

    Cysteine and MMSC reduced rebleeding/complications in NSAID gastric bleeding — protective sulphur‑donor effects in GI tissue.

  2. Role of sulphydryl-containing agents in the management of venous (varicose) ulceration. A new approach

    PubMed ID: 1486710

    Sulphydryl agents accelerated venous ulcer healing — supplies sulphur for tissue repair.

  3. Plasma glutathione of HIV⁺ patients responded positively and differently to dietary supplementation with cysteine or glutamine

    PubMed ID: 22261571

    NAC/glutamine supplementation raised cysteine and glutathione and affected methionine levels — demonstrates manipulation of sulfur amino acid pool.

  4. Effects of feed grade L-methionine on intestinal redox status, intestinal development, and growth performance of young chickens compared with conventional DL-methionine

    PubMed ID: 26115284

    L‑Met improved growth and protein accretion in chicks, consistent with supply of sulfur AAs to tissues.

  5. Efficacy of DL-methionine hydroxy analog free acid and DL-methionine as methionine sources for pigs

    PubMed ID: 16361496

    Pig studies show methionine supplementation improves growth and nitrogen retention, implicating sulfur provision for tissues in animals.

  6. Efficacy and tolerability of an oral supplement containing amino acids, iron, selenium, and marine hydrolyzed collagen in subjects with hair loss (androgenetic alopecia, AGA or FAGA or telogen effluvium). A prospective, randomized, 3-month, controlled, assessor-blinded study

    PubMed ID: 37357646

    Supplement containing methionine (a sulfur AA) improved hair outcomes—supports the role of sulfur‑containing AAs in keratinous tissue health (indirect).

  7. Intracellular amino acid concentrations in children with chronic renal insufficiency

    PubMed ID: 8611355

    Children with chronic renal failure had lower intracellular methionine, implying reduced sulfur‑containing amino acid availability for tissues—relevant to sulfur supply.

  8. Rumen-protected methionine compared with rumen-protected choline improves immunometabolic status in dairy cows during the peripartal period

    PubMed ID: 27592438

    Higher hepatic glutathione and related markers reflect increased cysteine/sulfur availability from methionine.

  9. Hepatic Activity and Transcription of Betaine-Homocysteine Methyltransferase, Methionine Synthase, and Cystathionine Synthase in Periparturient Dairy Cows Are Altered to Different Extents by Supply of Methionine and Choline

    PubMed ID: 27881594

    Hepatic enzyme shifts with methionine supplementation (including CBS) indicate flux into transsulfuration and sulfur amino‑acid metabolism.

  10. Effect of L-methionine on hot flashes in postmenopausal women: a randomized controlled trial

    PubMed ID: 19407666

    Direct L‑methionine supplementation increased serum methionine (and homocysteine), demonstrating increased sulfur‑amino‑acid availability.

Hormone balance (6)
  1. The influence of selenium supplementation on postpartum thyroid status in pregnant women with thyroid peroxidase autoantibodies

    PubMed ID: 17284630

    Large RCT: selenomethionine reduced postpartum thyroid dysfunction and permanent hypothyroidism—direct hormone outcome though Se-containing analog.

  2. Effects of rumen-protected methionine and choline supplementation on steroidogenic potential of the first postpartum dominant follicle and expression of immune mediators in Holstein cows

    PubMed ID: 28532823

    Rumen‑protected methionine raised follicular fluid methionine and upregulated steroidogenic (3β‑HSD) gene expression.

  3. Haemostatic effects of levothyroxine and selenomethionine in euthyroid patients with Hashimoto's thyroiditis

    PubMed ID: 22918596

    In euthyroid Hashimoto's patients, selenomethionine (often with levothyroxine) improved hemostatic markers linked to thyroid status—indirect hormone‑balance support.

  4. Effects of a six month treatment with selenomethionine in patients with autoimmune thyroiditis

    PubMed ID: 12656658

    Selenomethionine supplementation lowered thyroid autoantibodies in autoimmune thyroiditis — supports thyroid/hormone axis indirectly.

  5. Selenomethionine treatment in patients with autoimmune thyroiditis: a prospective, quasi-randomised trial

    PubMed ID: 22356267

    Selenomethionine supplementation lowered anti‑thyroglobulin antibodies in autoimmune thyroiditis—supports thyroid (hormone) modulation.

  6. The effect of levothyroxine and selenomethionine on lymphocyte and monocyte cytokine release in women with Hashimoto's thyroiditis

    PubMed ID: 21508145

    Selenomethionine lowered lymphocyte cytokine release and, with levothyroxine, reduced systemic inflammation in Hashimoto's—direct thyroid/hormone‑related effect (selenium‑methionine compound).

Digestive support (5)
  1. Regression of gastroesophageal reflux disease symptoms using dietary supplementation with melatonin, vitamins and aminoacids: comparison with omeprazole

    PubMed ID: 16948779

    A multi‑ingredient supplement that included methionine resolved GERD symptoms far more than omeprazole in a single‑blind trial (confounded by other ingredients).

  2. Sulphydryl-containing agents and the prevention of duodenal ulcer relapse

    PubMed ID: 8488172

    Methionine‑derived sulphydryl agent (MMSC) substantially reduced duodenal ulcer recurrence—direct digestive tract clinical benefit from a methionine derivative.

  3. Effects of feed grade L-methionine on intestinal redox status, intestinal development, and growth performance of young chickens compared with conventional DL-methionine

    PubMed ID: 26115284

    L‑Met improved intestinal morphology (villus height) and redox status in broilers — direct gut‑support evidence.

  4. Double-blind placebo-controlled multicenter phase II trial to evaluate D-methionine in preventing/reducing oral mucositis induced by radiation and chemotherapy for head and neck cancer

    PubMed ID: 29473247

    Oral D‑methionine substantially reduced severe mucositis and oral pain during chemoradiotherapy — direct mucosal/digestive benefit.

  5. Sulfhydryl-containing agents in the treatment of gastric bleeding induced by nonsteroidal anti-inflammatory drugs

    PubMed ID: 8443719

    Cysteine and methionine‑derived MMSC reduced rebleeding, transfusion and surgery in NSAID‑induced gastric bleeding — clear digestive tract protection.

Joint comfort (4)
  1. A randomized, double blind, placebo controlled trial of intravenous loading with S-adenosylmethionine (SAM) followed by oral SAM therapy in patients with knee osteoarthritis

    PubMed ID: 8064733

    IV load then oral SAMe reduced knee osteoarthritis pain in at least one center with effects by 2 weeks — clinical benefit for joint pain.

  2. A comparative clinical trial evaluating efficacy and safety of fixed dose combination of nimesulide (100 mg) and racemethionine (50 mg) (namsafe) versus reference drug (nimesulide) and other NSAIDs in the treatment of osteoarthritis

    PubMed ID: 18839654

    Racemethionine added to nimesulide was associated with greater relief of joint tenderness in patients (combination product).

  3. Comparative clinical trial of S-adenosylmethionine versus nabumetone for the treatment of knee osteoarthritis: an 8-week, multicenter, randomized, double-blind, double-dummy, Phase IV study in Korean patients

    PubMed ID: 20110025

    Moderate-sized RCT in Korean patients: SAMe reduced OA pain similarly to an NSAID over 8 weeks—direct clinical evidence for SAMe.

  4. S-adenosyl methionine (SAMe) versus celecoxib for the treatment of osteoarthritis symptoms: a double-blind cross-over trial. [ISRCTN36233495]

    PubMed ID: 15102339

    Randomized RCT: oral SAMe produced pain/function improvement comparable to celecoxib in knee osteoarthritis by 8 weeks—strong clinical evidence for SAMe (methionine metabolite).

Energy & Fatigue (3)
  1. Better postpartal performance in dairy cows supplemented with rumen-protected methionine compared with choline during the peripartal period

    PubMed ID: 27638261

    Improved feed intake and milk production reflect enhanced energy utilization/metabolic capacity with methionine supplementation in cows.

  2. Oral S-adenosylmethionine in the symptomatic treatment of intrahepatic cholestasis. A double-blind, placebo-controlled study

    PubMed ID: 2188871

    Oral SAMe improved fatigue in chronic intrahepatic cholestasis in addition to biochemical improvement — direct symptom (energy) improvement.

  3. A short-term intervention of ingesting iron along with methionine and threonine leads to a higher hemoglobin level than that with iron alone in young healthy women: a randomized, double-blind, parallel-group, comparative study

    PubMed ID: 37480367

    Methionine+threonine with low iron raised hemoglobin faster than iron alone — plausible effect on energy/oxygen delivery.

Skin appearance (2)
  1. Role of sulphydryl-containing agents in the management of venous (varicose) ulceration. A new approach

    PubMed ID: 1486710

    Adding cysteine/MMSC (sulphydryl agents including methionine derivative) markedly sped venous leg ulcer healing — direct skin healing benefit.

  2. Coenzyme Q(10), vitamin E, selenium, and methionine in the treatment of chronic recurrent viral mucocutaneous infections

    PubMed ID: 22079390

    Nutriceutical mix containing L‑methionine sped lesion healing and reduced viral skin lesion recurrences in controlled trials (multi‑ingredient).

Hair & Nails (1)
  1. Efficacy and tolerability of an oral supplement containing amino acids, iron, selenium, and marine hydrolyzed collagen in subjects with hair loss (androgenetic alopecia, AGA or FAGA or telogen effluvium). A prospective, randomized, 3-month, controlled, assessor-blinded study

    PubMed ID: 37357646

    Randomized trial of a multi‑ingredient oral supplement containing methionine (plus other AAs) improved clinician‑rated hair outcomes vs treatment alone.

Forms of L-Methionine

The form a label may print instead of L-Methionine. 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.

Zinc Monomethionine

A salt or solvate of L-Methionine.

Similar by evidence

Supplements the same benefits carry qualifying findings for — a fact about the evidence graph, not a recommendation to swap.

Copper

Shares 10 benefits: antioxidant, brain health, cell health, digestive support

Riboflavin

Shares 10 benefits: antioxidant, brain health, cell health, energy & fatigue

Alanine

Shares 10 benefits: detoxification, energy & fatigue, hair & nails, hormone balance

Alpha-Linolenic Acid

Shares 10 benefits: brain health, cell health, energy & fatigue, healthy aging

Niacin

Shares 10 benefits: brain health, cell health, detoxification, digestive support

Carnosine

Shares 10 benefits: antioxidant, brain health, cell health, energy & fatigue

Products with L-Methionine

Search all

3494 products whose verified label declares L-Methionine — not every bottle that mentions it in a title.

Vimerson Health

Glucosamine Chondroitin MSM

Glucosamine Sulfate Potassium (Shellfish-Free) 1500 mg, Boswellia Extract 65% Boswellic Acids (Boswellia serrata, Resin) 200 mg, Chondroitin Sulfate 150 mg +5 more

$20 – $30Chondroitin

Geritol

Liquid Energy Support, Iron and Vitamin Supplement, 12 Oz

Includes 7 g Added Sugars, Thiamin (as Thiamine HCI) 2.5 mg, Riboflavin (Vitamin B2) 2.5 mg +6 more

$10 – $15Diet & Sports Nutrition

NAKED

Whey 2LB 100% Grass Fed Whey Protein Powder

Includes 0g Added Sugars, Vitamin D 0mcg 0 mcg, Calcium 98 mg +19 more

$50 – $75Whey

Double Wood Supplements

EAA Capsules, BCAAs, All 9 Amino Acids, Workout + Muscle Recovery

L-Leucine 205 mg, L-Lysine 185 mg, L-Threonine 141 mg +6 more

$15 – $25BCAAs

BodyHealth

PerfectAmino (150 ct) Easy to Swallow Tablets, Essential

PerfectAmino Amino Acid Blend 5 g, L-Leucine 0 NP, L-Valine 0 NP +6 more

$35 – $55BCAAs

TryUvola

Uvola Milk Thistle Liver Detox

Vitamin C (as ascorbic acid) 10 mg, Milk thistle extract 300 mg, (Silybum marianum) (seed) +13 more

$30 – $50Milk Thistle

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.

Dietary Interventions During Living Kidney DonationsL-Methionine ¡ Living-Kidney Donors ¡ 80 participants planned ¡ ClinicalTrials.govRecruiting