The science behind erections is complicated, but what we do know is that nitric oxide is the chemical responsible for them. Because of this, nitric oxide—known by its formula, NO—is the quintessential ingredient in the most successful erectile dysfunction medications on the market.

Let’s find out what’s going on inside this compound.

The role of nitric oxide

Although sexual arousal begins in the brain, an erection is ultimately caused by physiological means: the release of nitric oxide. However, the production of NO is only part of a larger process.

First, the release of nitric oxide relaxes the smooth muscles that line the arteries that supply blood flow to the penis. This allows the arteries to increase in diameter, permitting sufficient blood flow for an erection.

Second, the release of nitric oxide produces cyclic guanosine monophosphate