DL-Methionine, DL Methionine, DL-Méthionine, L-2-amino-4-(methylthio)butyric acid, L-Methionine, L-Méthionine, Méthionine, Metionina.


Overview Information

Methionine is an amino acid. Amino acids are the building blocks that our bodies use to make proteins. Methionine is found in meat, fish, and dairy products. It plays an important role in the many functions within the body.

Methionine is commonly taken by mouth to treat liver disorders and viral infections along with many other uses. But there is limited scientific research that supports these uses.

How does it work?

In acetaminophen poisoning, methionine prevents the breakdown products of acetaminophen from damaging the liver. It may also act as an antioxidant and help to protect damaged tissues.


Uses & Effectiveness?

Possibly Effective for

  • Acetaminophen (Tylenol) poisoning. Research shows that taking methionine by mouth seems to be effective for treating acetaminophen poisoning. Treatment should begin as quickly as possible but must start within 10 hours of acetaminophen overdose.

Insufficient Evidence for

More evidence is needed to rate the effectiveness of methionine for these uses.

Side Effects

Side Effects & Safety

Methionine is LIKELY SAFE when taken by mouth in amounts commonly found in foods. It is POSSIBLY SAFE when taken by mouth or given intravenously (by IV) under the supervision of a healthcare professional. In some people, methionine may cause headache, heartburn, nausea, diarrhea, dizziness, or drowsiness.

Don't treat yourself with methionine. It is POSSIBLY UNSAFE to use methionine by mouth or intravenously to self-medicate. Too much methionine can cause brain damage and death. Methionine can increase blood levels of homocysteine, a chemical that may cause heart disease. Methionine might also promote the growth of some tumors.

Special Precautions & Warnings:

Children: Methionine is LIKELY SAFE for children when given by mouth in amounts commonly found in foods. It is POSSIBLY SAFE when given by IV, but only under the supervision of a healthcare professional. Methionine is POSSIBLY UNSAFE when given by IV into infants who are also receiving parenteral nutrition (nutrition through the vein).

Pregnancy and breast-feeding: Methionine is LIKELY SAFE when taken by mouth in amounts commonly found in foods. But there is not enough information about the safety of taking methionine in larger doses than those commonly found in foods. Stay on the safe side and avoid use.

Acidosis: Methionine can cause changes in acidity of the blood and should not be used in people with a condition called acidosis.

"Hardening of the arteries" (atherosclerosis): There is some concern that methionine might make atherosclerosis worse. Methionine can increase blood levels of a chemical called homocysteine, especially in people who don't have enough folate, vitamin B12, or vitamin B6 in their bodies, or in people whose bodies have trouble processing homocysteine. Too much homocysteine is linked to an increased risk for diseases of the heart and blood vessels.

Liver disease, including cirrhosis: Methionine might make liver disease worse.

Methylenetetrahydrofolate reductase (MTHFR) deficiency: This is an inherited disorder. It changes the way the body processes homocysteine. People who have this disorder should not take methionine supplements because methionine might cause homocysteine to build up in these people. Too much homocysteine might increase the chance of developing diseases of the heart or blood vessels.

Schizophrenia: Large doses of methionine (e.g., 20 g/day for 5 days) might cause confusion, disorientation, delirium, agitation, listlessness, and other similar symptoms in people with schizophrenia.



We currently have no information for METHIONINE Interactions.



The following doses have been studied in scientific research:



  • For acetaminophen (Tylenol) poisoning: 2.5 grams of methionine every 4 hours for 4 doses.

View References


  • Guttuso T Jr, McDermott MP, Ng P, Kieburtz K. Effect of L-methionine on hot flashes in postmenopausal women: a randomized controlled trial. Menopause 2009;16(5):1004-8.View abstract.
  • Hladovec J, Sommerova Z, Pisarikova A. Homocysteinemia and endothelial damage after methionine load. Thromb Res 1997;88:361-4. View abstract.
  • Kokko JP. Fluids and electrolytes. In: Goldman L, Bennett JC. Cecil Textbook of Medicine. 21st ed. Philadelphia, PA: W.B. Saunders Co. 2000:59.
  • La Vecchia C, Negri E, Franceschi S, Decarli A. Case-control study on influence of methionine, nitrite, and salt on gastric carcinogenesis in northern Italy. Nutr Cancer 1997;27:65-8. View abstract.
  • Meakins TS, Persaud C, Jackson AA. Dietary supplementation with L-methionine impairs the utilization of urea-nitrogen and increases 5-L-oxoprolinuria in normal women consuming a low protein diet. J Nutr 1998;128:720-7. View abstract.
  • National Research Council (US) Subcommittee on the Tenth Edition of the Recommended Dietary Allowances. Recommended Dietary Allowances: 10th Edition. Washington (DC): National Academies Press (US); 1989. 6, Protein and Amino Acids. Accessed August 7th, 2017.
  • Passaro M, Mainini G, Ambrosio F, Sgambato R, Balbi G. Effect of a food supplement containing L-methionine on urinary tract infections in pregnancy: a prospective, multicenter observational study. J Altern Complement Med 2017;23(6):471-8. View abstract.
  • Cottington EM, LaMantia C, Stabler SP, et al. Adverse event associated with methionine loading test: a case report. Arterioscler Thromb Vasc Biol 2002;22:1046-50.. View abstract.
  • De Luca C, Kharaeva Z, Raskovic D, Pastore P, Luci A, Korkina L. Coenzyme Q(10), vitamin E, selenium, and methionine in the treatment of chronic recurrent viral mucocutaneous infections. Nutrition 2012;28(5):509-14. View abstract.
  • Epner DE, Morrow S, Wilcox M, Houghton JL. Nutrient intake and nutritional indexes in adults with metastatic cancer on a phase I clinical trial of dietary methionine restriction. Nutr Cancer 2002;42:158-66.. View abstract.
  • Epner DE. Can dietary methionine restriction increase the effectiveness of chemotherapy in treatment of advanced cancer? J Am Coll Nutr 2001;20:443S-9S.. View abstract.
  • Frosst P, Blom HJ, Milos R, et al. A candidate genetic risk factor for vascular disease: a common mutation in methylenetetrahydrofolate reductase. Nat Genet 1995;10:111-3.. View abstract.
  • Fuchs CS, Willett WC, Colditz GA, et al. The influence of folate and multivitamin use on the familial risk of colon cancer in women. Cancer Epidemiol Biomarkers Prev 2002;11:227-34.. View abstract.
  • Girelli D, Martinelli N, Pizzolo F, et al. The interaction between MTHFR 677 C-->T genotype and folate status is a determinant of coronary atherosclerosis risk. J Nutr 2003;133:1281-5. View abstract.
  • Ward, M., McNulty, H., McPartlin, J., Strain, J. J., Weir, D. G., and Scott, J. M. Effect of supplemental methionine on plasma homocysteine concentrations in healthy men: a preliminary study. Int.J.Vitam.Nutr.Res. 2001;71(1):82-86. View abstract.
  • Yaghmai, R., Kashani, A. H., Geraghty, M. T., Okoh, J., Pomper, M., Tangerman, A., Wagner, C., Stabler, S. P., Allen, R. H., Mudd, S. H., and Braverman, N. Progressive cerebral edema associated with high methionine levels and betaine therapy in a patient with cystathionine beta-synthase (CBS) deficiency. Am.J.Med.Genet. 2-15-2002;108(1):57-63. View abstract.
  • Ahmed Ali U, Jens S, Busch OR, et al. Antioxidants for pain in chronic pancreatitis. Cochrane Database Syst Rev 2014;(8):CD008945. View abstract.
  • Anon. Should methionine be added to paracetamol formulations? Drug Ther Perspect 1997;10:11-3.
  • Barshop BA. Homocystiniuria. In: Goldman L, Bennett JC. Cecil Textbook of Medicine. 21st ed. Philadelphia, PA: W.B. Saunders Co. 2000:1115-6.
  • Bellamy MF, McDowell IF, Ramsey MW, et al. Hyperhomocysteinemia after an oral methionine load acutely impairs endothelial function in healthy adults. Circulation 1998;98:1848-52. View abstract.
  • Bellone J, Farello G, Bartolotta E, et al. Methionine potentiates both basal and GHRH-induced GH secretion in children. Clin Endocrinol (Oxf) 1997;47:61-4. View abstract.
  • Btaiche IF, Khalidi N. Parenteral nutrition-associated liver complications in children. Pharmacotherapy 2002;22:188-211.. View abstract.
  • Cassano N, Ferrari A, Fai D, et al. Oral supplementation with a nutraceutical containing Echinacea, methionine and antioxidant/immunostimulating compounds in patients with cutaneous viral warts. G Ital Dermatol Venereol 2011;146(3):191-5. View abstract.
  • Christensen B, Guttormsen AB, Schneede J, et al. Preoperative methionine loading enhances restoration of the cobalamin-dependent enzyme methionine synthase after nitrous oxide anesthesia. Anesthesiology 1994;80:1046-56. View abstract.
  • Trumbo, P., Schlicker, S., Yates, A. A., and Poos, M. Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein and amino acids. J Am.Diet.Assoc. 2002;102(11):1621-1630. View abstract.
  • Adams, J. M. and Capecchi, M. R. N-formylmethionyl-sRNA as the initiator of protein synthesis. Proc.Natl.Acad.Sci U.S.A 1966;55(1):147-155. View abstract.
  • CATONI, G. L. S-Adenosylmethionine; a new intermediate formed enzymatically from L-methionine and adenosinetriphosphate. J Biol.Chem. 1953;204(1):403-416. View abstract.
  • Cellarier, E., Durando, X., Vasson, M. P., Farges, M. C., Demiden, A., Maurizis, J. C., Madelmont, J. C., and Chollet, P. Methionine dependency and cancer treatment. Cancer Treat.Rev. 2003;29(6):489-499. View abstract.
  • Clark, B. F. and Marcker, K. A. How proteins start. Sci Am. 1968;218(1):36-42. View abstract.
  • Coelho CND, Klein NW. Methionine and neural tube closure in cultured rat embryos: morphological and biochemical analyses. Teratology 1990;42:437-451.
  • Douglas, A. P., Hamlyn, A. N., and James, O. Controlled trial of cysteamine in treatment of acute paracetamol (acetaminophen) poisoning. Lancet 1-17-1976;1(7951):111-115. View abstract.
  • Essien FB and Wannaberg SL. Methionine but not folinic acid or vitamin B-12 alters the frequency of neural tube defects in Axd mutant mice. J Nutr 1993;123:27-34.
  • Finkelstein, J. D. Homocysteine: a history in progress. Nutr Rev 2000;58(7):193-204. View abstract.
  • Hamlyn, A. N., Lesna, M., Record, C. O., Smith, P. A., Watson, A. J., Meredith, T., Volans, G. N., and Crome, P. Methionine and cysteamine in paracetamol (acetaminophen) overdose, prospective controlled trial of early therapy. J.Int.Med.Res. 1981;9(3):226-231. View abstract.
  • Hanratty, C. G., McGrath, L. T., McAuley, D. F., Young, I. S., and Johnston, G. D. The effects of oral methionine and homocysteine on endothelial function. Heart 2001;85(3):326-330. View abstract.
  • L-methionine and naltrexone for insomnia. Posit.Health News 1998;(No 17):19. View abstract.
  • Larsson, S. C., Giovannucci, E., and Wolk, A. Methionine and vitamin B6 intake and risk of pancreatic cancer: a prospective study of Swedish women and men. Gastroenterology 2007;132(1):113-118. View abstract.
  • Lu, S., Hoestje, S. M., Choo, E. M., and Epner, D. E. Methionine restriction induces apoptosis of prostate cancer cells via the c-Jun N-terminal kinase-mediated signaling pathway. Cancer Lett. 5-8-2002;179(1):51-58. View abstract.
  • McAuley, D. F., Hanratty, C. G., McGurk, C., Nugent, A. G., and Johnston, G. D. Effect of methionine supplementation on endothelial function, plasma homocysteine, and lipid peroxidation. J.Toxicol.Clin.Toxicol. 1999;37(4):435-440. View abstract.
  • Meininger, V., Flamier, A., Phan, T., Ferris, O., Uzan, A., and Lefur, G. [L-Methionine treatment of Parkinson's disease: preliminary results]. Rev.Neurol.(Paris) 1982;138(4):297-303. View abstract.
  • Moss, R. L., Haynes, A. L., Pastuszyn, A., and Glew, R. H. Methionine infusion reproduces liver injury of parenteral nutrition cholestasis. Pediatr.Res. 1999;45(5 Pt 1):664-668. View abstract.
  • Sasamura, T., Matsuda, A., and Kokuba, Y. Effects of D-methionine-containing solution on tumor cell growth in vitro. Arzneimittelforschung. 1999;49(6):541-543. View abstract.
  • Shaw, G. M., Velie, E. M., and Schaffer, D. M. Is dietary intake of methionine associated with a reduction in risk for neural tube defect-affected pregnancies? Teratology 1997;56(5):295-299. View abstract.
  • Shoob, H. D., Sargent, R. G., Thompson, S. J., Best, R. G., Drane, J. W., and Tocharoen, A. Dietary methionine is involved in the etiology of neural tube defect-affected pregnancies in humans. J.Nutr. 2001;131(10):2653-2658. View abstract.
  • Smulders, Y. M., Rakic, M., Slaats, E. H., Treskes, M., Sijbrands, E. J., Odekerken, D. A., Stehouwer, C. D., and Silberbusch, J. Fasting and post-methionine homocysteine levels in NIDDM. Determinants and correlations with retinopathy, albuminuria, and cardiovascular disease. Diabetes Care 1999;22(1):125-132. View abstract.
  • TABOR, H., ROSENTHAL, S. M., and TABOR, C. W. The biosynthesis of spermidine and spermine from putrescine and methionine. J Biol.Chem. 1958;233(4):907-914. View abstract.
  • Tan, Y., Zavala, J., Sr., Xu, M., Zavala, J., Jr., and Hoffman, R. M. Serum methionine depletion without side effects by methioninase in metastatic breast cancer patients. Anticancer Res. 1996;16(6C):3937-3942. View abstract.
  • Russman S, Junker E, Lauterburg BH. Remethylation and transsulfuration of methionine in cirrhosis: studies with L-[H3-methyl-1-C]methionine. Hepatology 2002;36:1190-6.. View abstract.
  • Su LJ, Arab L. Nutritional status of folate and colon cancer risk: evidence from NHANES I epidemiologic follow-up study. Ann Epidemiol 2001;11:65-72.. View abstract.
  • Talukdar R, Murthy HV, Reddy DN. Role of methionine containing antioxidant combination in the management of pain in chronic pancreatitis: a systematic review and meta-analysis. Pancreatology 2015;15(2):136-44. View abstract.
  • Vale JA, Meredith TJ, Goulding R. Treatment of acetaminophen poisoning. The use of oral methionine. Arch Intern Med 1981;141:394-6. View abstract.
  • Ward M, McNulty H, Pentieva K, et al. Fluctuations in dietary methionine intake do not alter plasma homocysteine concentrations in healthy men. J Nutr 2000;130:2653-7.. View abstract.
  • Wu W, Kang S, Zhang D. Association of vitamin B6, vitamin B12 and methionine with risk of breast cancer: a dose-response meta-analysis. Br J Cancer 2013;109(7):1926-44. View abstract.
  • Zhou ZY, Wan XY, Cao JW. Dietary methionine intake and risk of incident colorectal cancer: a meta-analysis of 8 prospective studies involving 431,029 participants. PLoS One 2013;8(12):e83588. View abstract.

Vitamins Survey

Have you ever purchased METHIONINE?

Did you or will you purchase this product in-store or online?

Where did you or where do you plan to purchase this product?

Where did you or where do you plan to purchase this product?

What factors influenced or will influence your purchase? (check all that apply)

Vitamins Survey

Where did you or where do you plan to purchase this product?

Do you buy vitamins online or instore?

What factors are most important to you? (check all that apply)

This survey is being conducted by the WebMD marketing sciences department.Read More

More Resources for METHIONINE

CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version.
© Therapeutic Research Faculty .