Amino acids

Amino acids are the building blocks of proteins. Proteins contribute to muscle mass growth and to maintaining muscle mass, and are important for the skeleton. Some of the amino acids can be produced by the body itself, while those called essential must be supplied through the diet; these are arginine, phenylalanine, histidine, isoleucine, leucine, lysine, methionine, threonine, tryptophan, and valine.