L-Methionine Side Effects

L-Methionine is an essential amino acid. It is beneficial in treating liver disease and benefits skin tone and elasticity, nails and hair. It is also important for proper cardiovascular and muscular functions and is used in the treatment of chronic depression. Though it’s considered safe, some are convinced it has potentially dangerous health effects.

What Is L-Methionine?

L-Methionine is a white crystalline powder and an essential amino acid found in high protein foods such as meat, fish, and dairy. This amino acid is used to help the body break down fat, build muscle, and aid in the removal of heavy metals from the body to ensure proper functioning of the liver, kidneys, and bladder. L-Methionine is used as a nutritional food additive and is of particular interest to vegetarians and vegans who may not ingest enough protein in their normal diet.

Possible Side Effects of L-Methionine

Although L-Methionine generally regarded as a very safe and effective supplement, there can be some minor side effects. The side effects may:

  • Drowsiness
  • nausea and vomiting

GRAS Affirmation: Yes

Generally recognized as safe (GRAS) is an American Food and Drug Administration (FDA) designation that a chemical or substance added to food is considered safe by experts, and so is exempted from the usual Federal Food, Drug, and Cosmetic Act (FFDCA) food additive tolerance requirements. L-Methionine is considered safe.

Suggested Dosage


Special Populations Precaution

There is a lot of concern about diet and nutrition for these population, like Newborns, children, pregnant, sensitive to Glucono Delta Lactone populations. Better consult to your doctor if you would like to intake L-Methionine.




Related Research

1. 2-keto-4-(methylthio)butyric acid (keto analog of methionine) is a safe and efficacious precursor of L-methionine in chicks. [J Nutr. 2007 Aug] Author: Dilger RN, Kobler C, Weckbecker C, Hoehler D, Baker DH.

2. The keto acid of methionine is a safe and efficacious substitute for dietary L-methionine: the answer from chick bioassays. [J Nutr. 2007 Aug] Author: Stipanuk MH.

3. Treatment of AIDS-associated myelopathy with L-methionine: a placebo-controlled study. [Neurology. 2004 Oct 12] Author: Di Rocco A, Werner P, Bottiglieri T, Godbold J, Liu M, Tagliati M, Scarano A, Simpson D.

4. Does L-Methionine Have Health Benefits? A Scientist Explains

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