Viagra like other erectile dysfunction treatments is very simple to take, but it's mechanism of action is rather complex. Of course, when you deal with such a complex process like erection, the treatment should be adequate. A very important component of both natural and drug-induced erections is nitric oxide, a chemical transmitting impulses of sexual arousal between different nerves and relaxing the smooth muscles in the penis shaft, stimulating more blood to flow into the penis.

Nitric oxide is very important for a strong and stable erection, but there are more elements to it. It causes the arterial cells to produce cyclic guanosine monophosphate (cGMP), the substance that stimulates the blood circulation in the penis shaft. And penile tissues also produce phosphodiesterase-5 (PDE5), a chemical that breaks down cGMP.

In a normal situation, there is enough cGMP generated in the penis for producing a strong erection and enough PDE5 to dissolve the erection after ejaculation. But in case of erectile dysfunction, this gentle balance is disturbed, and Viagra like other ED medications works by restoring this balance. All these drugs are PDE5-inhibitors, which means that they restrict this chemical's production, thus increasing the level of cGMP. In most cases of erectile dysfunction the increased supply of cGMP results in adequate erections that are obtained during sexual stimulation.

But does Viagra and other erectile dysfunction medications work? Well, they do, and in contrast to the battles in the media and on the market, they are all pretty much the same in their mechanism of action and effectiveness. About 70% of men with erection problems have positive results when using these drugs, but the percentage may vary according to the cause of impotence. For example, men who don't have serious physiological conditions have a 90% success rate, while those with diabetes — only 50%. Other conditions can have even lower success figures.