Branched-chain amino acid (BCAA) is a combination of three amino acids which have branched molecular structure – leucine, isoleucine and valine. In the form of food supplements they can be found most commonly in three different ratios: 2:1:1, 4:1:1 and 8:1:1. BCAAs are classified as essential amino acids, hence they are not synthesized in the human body and must be received from food or food supplements. BCAAs have fundamental function in the muscle cell protein synthesis, as they stimulate muscle growth and protect muscle tissue from catabolism (disintegration). During intensive workouts the increased intake of BCAA reduces tiredness, helps muscle recovery and growth and protects the muscle tissue from disintegration. The additional intake of BCAAs is recommended for all types of workouts due to their fundamental role in the muscle metabolism.