Ornithine helps to maintain and build up the immune system and to regenerate the liver. It takes part in the release of growth hormone and is often used in conjunction with Arginine. Ornithine is a precursor of Citruline and Arginine and, when given orally, has very similar biological effects. It is a naturally occurring Amino Acid and is different from Arginine in that it is not found incorporated into body proteins. Amino acids are essential to health. Most form the small structural components of protein and are required for the synthesis of protein within the body. The primary function of most amino acids is to furnish the essential material for duplication of the genetic code, for cell division, and for the formation of muscles and connective tissue.