Do alot of Men use Viagra?

[carlos marvado]

I have heard from some people that there are side effects including headaches and bleeding. From my limit knowledge, original Viagra (from Pfizer) is only available from pharmacies with a prescription. The cheapo stuff that is available on the internet and other unreliable sources seems to be coming from China and I'm sure that some time in the future, we will learn what the long term effects of using this are.