Arginine is an amino acid that is best known as a growth hormone releaser. Arginine (2-amino-5-guanidinovaleric acid) is an alpha amino acid that has garnered significant research interest for its involvement in a several physiological and pathophysiological processes in human health and disease. Arginine is used for a number of biological processes, including being available to be broken down into chemical intermediates that replenish the Krebs Cycle. Arginine is an ESSENTIAL amino acid for cats. (Read More: The Journal of Nutrition, Volume 108, Issue 12, December 1978 and Wikipedia).