About L-Methionine

L-methionine is an essential amino acid. The human body cannot manufacture this amino acid and must obtain it from the daily diet. The male adult’s daily requirement is 13 mg per kg of body weight. L-methionine deficiency is unlikely as it is readily available from meat, fish, dairy and other high protein foods.


In pharmaceutical preparations, L-methionine is used in hepatic therapeutics and drugs for preventing hepatic impairments. L-methionine is used as a nutritive element in infant milk preparations, health foods and as a component of sports supplements. Supplementing the diet with L-methionine is not recommended unless directed by a physician.


L-methionine is manufactured by optical resolution of the DL-form, which is manufactured by chemical synthesis using acrolein as the starting material. L-methionine is manufactured under cGMP conditions; no materials of animal origin are used in the production process. L-methionine from Ajinomoto meets USP, EP and JP standards. A Drug Master file for L-methionine is on file at the FDA.

L Methionine

Abbreviation: L-Met
CAS Number: 63-68-3
Conforms To: JP,USP,EP
Chemical Name: (2S)-2-Amino-4 -(methylsulfanyl) Butanoic Acid
Chemical Formula: C5H11NO2·S
Molecular Weight: 149.2100
Nitrogen Content: 0.0939
Assay: 99.0 tp 101.0%
Solubility: Soluble in water
Description: White crystals or crystalline powder; characteristic odor

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