Promotes lean muscle. Initiated anabolic response. Vital for protein synthesis. Essential amino acid. Pharmaceutical Grade. Leucine is an essential amino acid: as an essential amino acid, leucine cannot be made by the body, and must be acquired through food or dietary supplements. Leucine is classified as a branched chain amino acids (BCAA). It comprise about 8% of the total amino acids in your body's protein structures and is the fourth most concentrated amino acid in skeletal muscle tissue. Leucine stimulates muscle protein synthesis: leucine may be the major fuel involved in anabolic (tissue building) reactions. This mistakes leucine especially important for body builders and other athletes that demand explosive strength. The branched chain amino acids, valine, leucine, and isoleucine, enhance protein synthesis in liver cells and muscle cells and help promote muscle recovery after exercise. BCAA's contribute to energy production in the body by being oxidized in the cells mitochondria. BCAAs are used by bodybuilders and micro tears in muscle tissue that are a normal results of exercise. Leucine is thought to be the most effective BCAA for preventing the body's burning of muscle stores for energy during intense workouts because it is converted to glucose more quickly than isoleucine and valine.