Arginine meet sometimes in the form of “AAKG”, especially as a supplement or an ingredient supplements for athletes. L-arginine is a free, natural form of the amino acid and AAKG a molecule consisting of arginine and alpha-ketoglutaric acid. In other words, it arginine + AKG (keto acid, glutaric acid derivative). AAKG form is more stable after digestion as well as more effective, but it is an artificial creation. Other frequently used in suplementch forms of arginine is arginine hydrochloride (well soluble in water, but cheap b. A bitter and average absorbed) and arginine malate (well bioavailable, easily absorbed, acting quickly, but briefly).