Both arginine and alpha-ketoglutaric acid are precursors to nitric oxide (NO) production. The rate-limiting step of amino acid uptake into skeletal muscle is the transportation of the amino acids through the blood to the skeletal muscle, which is governed by blood flow (Wolfe 2004). NO vasodilates blood vessels, thereby increasing blood flow. This increase when combined with exercises means greater blood flow and greater amino acid deliver and uptake in the working skeletal muscle. Exercise itself results in an increase in NO production, and the increased blood flow created by exercise is believed to be linked to the increase in protein synthesis post workout (Douglas et al. 2004). Arginine is a precursor for NO production. Supplementing with exogenous Arginine increases NO production and therefore blood vessel dilation and blood flow, which will also for great nutrient deliver (i.e. amino acids) to skeletal muscle. Arginine is also involved in hormone secretion, wound healing, and immune system functioning (Tong & Barbul 2004). Alpha-ketoglutaric acid is a vital intermediate in the Kreb's energy cycle, used in the formation of amino acids, and a nitrogen/ammonia transporter. The combination of alpha-ketoglutaric acid's benefits with arginine's benefits give AAGK a clear edge over standard L-arginine.