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What other names is Methionine known by?

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

What is Methionine?

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, and it plays an important role in many cell functions.

Methionine is used to prevent liver damage in acetaminophen (Tylenol) poisoning. It is also used for increasing the acidity of urine, treating liver disorders, and improving wound healing. Other uses include treating depression, alcoholism, allergies, asthma, copper poisoning, radiation side effects, schizophrenia, drug withdrawal, and Parkinson's disease.

Possibly Effective for...

  • Acetaminophen (Tylenol) poisoning. Research shows that receiving methionine by mouth or intravenously (by IV) 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 to Rate Effectiveness for...

  • Cobalamin deficiency. Long-term exposure to nitrous oxide, which is given for anesthesia during surgery, might cause side effects that resemble cobalamin deficiency. Some research suggests that taking methionine by mouth before surgery might reduce these side effects of nitrous oxide.
  • Colon cancer. Eating a diet that rich in methionine and folate (a type of B vitamin) seems to help reduce the risk of colon cancer. This seems to be especially true for people with a family history of colon cancer and people who drink large amounts of alcohol.
  • Neural tube birth defects. Women who consume more dietary methionine during pregnancy seem to have a lower risk of neural tube birth defects.
  • Parkinson's disease. Early research suggests that taking L-methionine by mouth for up to 6 months improves symptoms of Parkinson's disease, such as tremor, inability to control movements, and rigidity.
  • Liver function.
  • Depression.
  • Alcoholism.
  • Allergies.
  • Asthma.
  • Radiation side effects.
  • Schizophrenia.
  • Drug withdrawal.
  • Other conditions.
More evidence is needed to rate the effectiveness of methionine for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

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