To understand more clearly the effect of Cialis, let’s review the biochemical mechanism of erection’s appearance. For invention of this mechanism creators of Viagra received Nobel Prize.

Briefly, the nature of biochemical mechanism of erection is as follows: nitric oxide is to be released in the tissues of penis during sexual stimulation. It causes to creation of cyclic guanosine monophosphate, this substance results to relaxation of smooth muscles of penis.


Due to action of this substance, the blood fills penis, and it causes to natural excellent erection.  Besides, it will be interesting to know that nocturnal erections are not the result of erotic dreams, but are caused of relaxation of smooth muscles in penis. However, when cyclic guanosine monophosphate penetrates into blood, organism begins to secrete enzyme PDE 5 (phosphodiesterase of 5-type). This substance begins to destroy cyclic guanosine monophosphate. After the reduction of the level of cyclic guanosine monophosphate in blood, there is an outflow of blood from penis and erection disappears.