Amino Acids - Introduction - Essential vs. Non

Proteins are synthesized from twenty different amino acids. The liver produces eleven "non-essential" amino acids while the remaining nine "essential" amino acids must be obtained from the diet.

A deficiency of even one essential amino acids can result in severe physiological problems. It is important to obtain all essential amino acids from a variety of dietary sources (see Sources and Combinations, below). The essential amino acids are: L-histidine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-threonine, tryptophan, and L-valine.

Non-essential amino acids are manufactured by the body as needed. They are required for proper health and growth, but it is not necessary to obtain them through the diet as with the essential amino acids. The non-essential amino acids are: L-alanine, L-arginine, asparagine, aspartic acid, citrulline, L-cysteine and cystine, gamma-aminobutyric acid, glutamic acid, L-glutamine, glycine, ornithine, L-proline, L-serine, L-taurine, and L-tyrosine.