Herbs & Supplements:
Methionine

Supplement Forms / Alternate Names
  • L-Methionine
Principal Proposed Uses
  • · There are no well-documented uses for methionine
Other Proposed Uses
  • Urinary Tract Infections, "Liver Support", Parkinson's Disease

Methionine is an essential amino acid—one of the building blocks of proteins and peptides that your body cannot manufacture from other chemicals. The body uses methionine to manufacture creatine and uses the sulfur in methionine for normal metabolism and growth.

One preliminary study suggests that methionine can prevent bacteria from sticking to urinary tract cells,¹which may make it useful for preventing bladder infections. (Cranberry juice is thought to help reduce the incidence of bladder infections in a similar fashion.)

Requirements/Sources

Depending on your body weight, you need between 800 and 1,000 mg of methionine daily for normal health. Deficiency is unlikely, because enough methionine is generally available from the diet.

Meat, fish, dairy products, and other high-protein foods are good sources of methionine.

Therapeutic Dosages

A proper therapeutic dosage of methionine has not been determined. One study relating to urinary tract infections used a dosage of 500 mg 3 times daily.

Therapeutic Uses

Because it seems to discourage bacteria from sticking to the wall of the bladder, methionine has been suggested as a treatment for recurrent bladder infections.² However, the evidence that it works is limited to one small trial without placebo control.

One study on rats suggests that methionine might protect the liver against acetaminophen (e.g., Tylenol) poisoning.³ Based on this, it has been proposed as a generally helpful substance—what our great-grandparents might have called a "tonic"—for the liver. However, in this particular study the action of methionine was more to fight acetaminophen specifically than to protect the liver in general.

Very preliminary evidence suggests methionine might be helpful in treating Parkinson's disease (however, this should not be attempted except under physician supervision; see Safety Issues).^4,5

Safety Issues

Methionine is thought to be generally safe. However, the maximum safe dosages for young children, pregnant or nursing women, or those with serious liver or kidney disease have not been established.

Like other amino acids, methionine may interfere with the absorption or action of the drug levodopa, which is used for Parkinson's disease.⁶

Interactions You Should Know About

If you are taking

• Methionine: Make sure to get enough folate, vitamin B₆, and vitamin B₁₂.⁷
• Levodopa: Methionine might interfere with its action.

Last reviewed March 2002 by Medical Review Board

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