AKA: Nitric Oxide
The Mythology: Pre-workout jet fuel. Tunes you up like a muscle car on nitrous.
The Truth: Delays fatigue and improves strength. Not quite the same robust evidence base as Creatine though. Getting there?
Research: Arginine supplementation is believed to enhance levels of Nitric Oxide in the blood, causing dilation of blood vessels in the muscle, much the same way Sildenafil (Viagra) does in the penis (eep!)
Most studies have been conducted on sick people ie: those with coronary or pulmonary diseases. In terms of the evidence for improving exercise parameters in healthy individuals the evidence is shaky but intriguing. Studies have demonstrated improvements in muscular strength, fatigue and endurance both in trained and untrained men. 1.2.3.
A recent study found that untrained men could improve their fatigue thresholds significantly by consuming arginine supplements for 4 weeks 4. I suspect that future studies on trained individuals will make things clearer in the years ahead, quite possibly in the favour of arginine. In the meantime I’d definitely urge you to try it out and see what your own individual response is like.
1. Campbell, B, Roberts, M, Kerksick, C, Wilborn, C, Marcello, B, Taylor, L, Nassar, E, Leutholtz, B, Bowden, R, Rasmussen, C, Greenwood, M, and Kreider, R Pharmacokinetics, safety, and effects on exercise performance of L-arginine ct-ketoglutarate in trained adult men. Nutrition 22: 872-881, 2004.
2. Chen, S, Kim, W, Li, Z, and Heber, D. The effect of an L-arginine containing supplement on exercise performance in middle-aged and elderly men. Exp Biol 2006
3. Steven, BR, Godfrey, MD, Kaminski, TW, and Braith, RW. High-intensity dynamic human muscle performance enhanced by a metabolic intervention. Med Sd Sports Exerc 32: 2102-2108, 2000
4. Camic, Clayton L; Housh, Terry J; Zuniga, Jorge M; Hendrix, Russell C; Mielke, Michelle; et al. Journal of Strength and Conditioning Research 5 (May 2010): 1306-12.
How it works: Arginine contributes to the removal of excess ammonia from the body and the synthesis of muscle protein, other amino acids, and creatine. It is the precursor of nitric oxide (NO) and thus plays a crucial role in endothelium-dependent vasodilation. Therefore, one of the proposed benefits of arginine supplementation is increased blood flow in the skeletal muscle during exercise, enhancing strength and over a period of time – muscle mass. It also reduces the formation of metabolic waste products in muscle such as lactate.
Adverse effects: Infrequent reports of nausea, diarrhoea and bitterness.