is an essential branched-chain amino acid (BCAA) that's broken down in fat structures. It helps preserve lean muscle tissue, it supplies the body with energy when under stress (i.e. when engaging in athletic activity), it may help to preserve muscle glycogen (glucose stored in muscle tissue used to power muscular contraction), along with supporting nitrogen balance.* As the strongest of the BCAA's, L-Leucine is what's known as a "limiting nutrient" - meaning that no matter how much protein you consume, if you are deficient in L-Leucine, your body will not be able to make use of the protein for muscular gains no matter how much you consume.
is probably best known for its use in increasing endurance and helping heal and recover muscle tissue. Serious athletes and bodybuilders need this amino acid because of its ability to support muscular energy levels (it is broken down within the muscle tissue to provide energy), it may also support glucose uptake into muscle cells, and also it helps muscular recovery following strenuous exercise and other physical activities.*
is a BCAA that is found in high concentration in the muscles. It has a stimulating effect and is needed for muscle metabolism, recovery and growth of tissue and maintaining the nitrogen balance in the body. Since it is a branched-chain amino acid, it can be used as an energy source in the muscles, and in doing so, preserves the use of glucose, allowing you to train longer and harder.*