Isoleucine, available in most food sources, is particularly high in many fish and meats, in cheeses, and relatively high in wheat germ and most seeds and nuts. L-isoleucine is a branched amino acid found in high concentrations in our muscle tissues. It is used in the body to produce certain biochemical compounds that help in energy production and has been found experimentally to reduce twitching and tremors in animals. The branched-chain amino acids (BCAA)—isoleucine, leucine, and valine—have been used as supplements for body (muscle) building.