Valine is essential for muscle metabolism, the repair of damaged tissue and the maintenance of normal nitrogen metabolism in the body. In the case of a negative nitrogen balance, the body is forced to destroy functional tissues and skeletal muscles to produce energy. Most often this does not pose a big threat, since in an adult body the protein content is relatively constant and as many amino acids are oxidized as a person receives from food.
It is classified as a branched-chain amino acid, which means that it can be used by muscles as an energy source.
Valine is often used to correct severe amino acid deficiencies resulting from drug addiction.