Branched-chain amino acids (BCAAs) are great supplements for bodybuilders, athletes, and all active people. BCAAs have been popular for many years due to their many health benefits. They contain a combination of the amino acids leucine, iso-leucine, and valine. These are classified as “essential” amino acids because the body does not produce them naturally, meaning you have to get them from your diet or from supplement sources. Some other essential amino acids include lysine, tryptophan, methionine, and phenylalanine.