Branched-chain amino acids (BCAAs) are essential nutrients including leucine, isoleucine, and valine. They're found in meat, dairy, and legumes.

BCAAs stimulate the building of protein in muscle and possibly reduce muscle breakdown. The "Branched-chain" refers to the chemical structure of these amino acids.

BCAAs are used for reduced brain function in people with advanced liver disease and for a movement disorder often caused by antipsychotic drugs. They are also commonly used to improve athletic performance, prevent fatigue, reduce muscle breakdown, and other purposes.