Thanks to its long-lasting effects, this product has become one of the most popular ingredients for treating erectile dysfunction and impotence. Viagra is a reversible phosphodiesterase type 5 inhibitor on the action of cyclic guanosine monophosphate.

It is recommended to take only one 100mg dose at least 30 minutes before sexual intercourse. Note that Viagra is known to maintain erection and have a much longer orgasm.