Branch Chain Amino Acids (BCAA's) are 3 of the 10 Essential Amino Acids. Essential Amino Acids cannot be produced by your body and must be derived from food. Protein is high in Essential Amino Acids and is an excellent source. If protein is not available or is inconvenient, BCAA's can be used in order to signal muscle protein synthesis.The three BCAA's are Leucine (the anabolic trigger), Isoleucine, and Valine. NutraBio BCAA caps use only the highest quality BCAA's and are third-party tested to ensure quality and purity.