Arginine, an amino acid, is the precursor of nitric oxide, which plays a number of important roles in the body. Nitric oxide acts as vasodilator (blood vessel relaxant) and helps deliver blood flow to muscle tissues.
A recent study examined the effect of 4 weeks of arginine supplementation to determine if it can boost performance in untrained men.
Fifty college-aged men were randomized into 1 of 3 groups who took 1.5g of arginine plus 300 mg of grape seed extract, 3g of arginine plus 300 mg of grape seed extract or a placebo.
Before supplementation and after 4 weeks of supplementation, subjects performed an incremental test to exhaustion on a cycle ergometer. There were significant mean increases in physical work capacity for the 1.5g (22.4%) and 3g (18.8%) arginine groups, but no change for the placebo group (-1.6%). The authors of this study conclude, “These findings supported the use of arginine-based supplements, at the dosages examined in the present investigation, as an ergogenic aid for untrained individuals.”