Nitric oxide activates cGMP, a molecule that relaxes blood vessel walls and increases blood flow. This is how arginine supplements and drugs like Viagra work at the cellular level.
Turns out that the one that's responsible for vascular relaxation is called cyclic GMP, G like George, and it is triggered in the same process as nitrates such as nitric oxide. So if we give nitric oxide or we give you arginine and it raises your nitric oxide, the cyclic GMP system kicks in and then the vascular muscle, so your blood vessels have muscle in them, the vascular muscle relaxes. And what that does is that makes the vascular, the level inside the vessel larger, so the diameter, if you will, larger. That means more blood can flow through.
