Leucine is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and a side chain isobutyl group, making it a non-polar aliphatic amino acid. It is essential in humans, meaning the body cannot synthesize it: it must be obtained from the diet. Human dietary sources are foods that contain protein, such as meats, dairy products, soy products, beans and other legumes. 

1. Leucine is a branched-chain amino acid    
2. Leucine can be used as dietary supplement, and Leucine is utilized in the liver, adipose tissue, and muscle tissue.    
3. As one of the three BCAA's, L-Leucine is essential to your basic health. It has both athletic and medical applications.
3.L-Leucine maintains nitrogen balance, and it has also been shown to enhance thinking abilities that can decline as physical activity becomes more intense.   
4. L-Leucine also works to heal bone, skin and muscle tissue.