Arginine is a precursor for nitric oxide, which relaxes vascular smooth muscle leading to improved blood flow and, thus, the flow of nutrients to muscles (1;2). Oral arginine appears to also stimulate growth hormone release, especially when taken with exercise (3). Supplementation with arginine didn’t increase body mass significantly in a study in 2008; although, when taken with creatine, arginine did improve endurance and power of muscle (2).
1. Gropper SS, Smith JL, Groff JL. Advanced Nutrition and Human Metabolism. Belmont, CA: Thomson Wadsworth, 2009.
2. Little JP, Forbes SC, Candow DG, Cornish SM, Chilibeck PD. Creatine, arginine alpha-ketoglutarate, amino acids, and medium-chain triglycerides and endurance and performance. Int J Sport Nutr Exerc Metab 2008;18:493-508.
3. Kanaley JA. Growth hormone, arginine and exercise. Curr Opin Clin Nutr Metab Care 2008;11:50-4.