Nitric oxide acts as a vasodilator, which means it helps open blood vessels. As a result, many people take the precursor L-arginine for issues like erectile dysfunction and to improve heart health.

Nitric oxide works as a signalling molecule in the cardiovascular, nervous and immune systems of animals, and is mostly produced in the inner layer of blood vessels called the endothelium.

A team of Hopkins scientists has greatly advanced the science of penile erection, showing for the first time the mechanism for continued production of nitric oxide that maintains an erection over ...