The phrase branched-chain amino acids or BCAA is used to refer to the amino acids having aliphatic side-chains that are non-linear. These are leucine, isoleucine and valine. The combination of these three essential amino acids makes up approximately 1/3 of skeletal muscle in the human body, and plays an important role in protein synthesis. BCAA’s are currently used clinically to aid in the recovery of burn victims, as well as for supplementation for strength athletes. BCAA may also be used to improve your diet. It may be used to treat loss of appetite and liver problems, such as cirrhosis (sir-O-sus).