What does nitric oxide do to muscles?

Blood Flow: Nitric oxide increases the blood flow in blood vessels by causing them to expand. This is suppose to be the theory behind the supplements that are used to build muscles. By increasing blood flow you also increase the glucose and protein delivery to the muscle and stimulate its growth.

Increases blood flow: Nitric oxide has been marketed as a performance enhancer for athletes - Nitric Oxide increase blood flow to muscles and helps to maintain the 'pumped up' look after lifting weights. Some studies have suggested improved endurance. Arginine is actually the ingredient in the Nitric Oxide that is sold in health and nutrition stores. It is converted to Nitric Oxide hope this helps.