There are several types of BCAAs: leucine, valine and isoleucine. They all help the muscles make proteins. Considering leucine for example, it rebuilds, repairs muscle tissues and there is some evidence that it may help improve muscle mass, recovery, inflammation, and blood sugar levels. Valine also promotes muscle growth and tissue repair, and serves a precursor in the penicillin biosynthetic pathway. Valine is one of three branched-chain amino acids that enhance energy, increase endurance, and aid in muscle tissue recovery and repair.