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.
Plants, unlike other higher eukaryotes, possess all the necessary enzymatic equipment for de novo synthesis of methionine, an amino acid that supports additional roles than simply serving as a building block for protein synthesis. This is because methionine is the immediate precursor of S-adenosylmethionine (AdoMet), which plays numerous roles of being the major methyl-group donor in transmethylation reactions and an intermediate in the biosynthesis of polyamines and of the phytohormone ethylene.
A mixture of the two is called DL-methionine. Methionine is a sulfur-containing amino acid that improves the tone and elasticity of the skin, promotes healthy hair and strengthens the nails.
For oral dosage form (capsules): Adults and teenagers—The usual dose is 200 milligrams (mg) three or four times a day. Children—The usual dose is the contents of 1 capsule (200 mg) added to a warm bottle of milk or formula in the evening, or added to a glass of juice or water.