CL Review: L-Arginine Ups Endurance

WHITE PLAINS, N.Y.Nitric oxide supplements didn't increase muscle size or fullness, but supplements with L-arginine increased intense exercise endurance in older and recreational athletes, in a ConsumerLab.com review of clinical studies of supplements used to increase nitric oxide in the body. ConsumerLab.com said the supplements appear to do little for trained athletes.

The review reported nitric oxide supplements dont actually provide nitric oxide, which is a gas, but generally contain L-arginine which can, in some people, increase nitric oxide. Nitric oxide, in turn, potentially increases blood flow to muscles and other organs.

L-arginine supplements may also be helpful in people with cardiovascular conditions such as angina or atherosclerosis, ConsumerLab.com noted.

The specific dosages and other details are provided in a "Nitric Oxide Supplements Review" published online for ConsumerLab.com members. The report links to ConsumerLab.coms tests and quality ratings of specific L-arginine supplements and cites potential side-effects and cautions when using such supplements.