Cialis does not cause a man to be sexually aroused. Cialis will only be effective if a man is mentally sexually aroused. To understand how Cialis works you need to understand the mechanics of how a man gets an erection. When a man is sexually stimulated, the nervous system in the erectile tissue of your penis releases nitric oxide (NO). The nitric oxide stimulates an enzyme that produces a ‘messenger’ called cyclic guanosine monophosphate (cGMP). The cGMP relaxes the smooth muscle cells.

How quickly does it works?

One result of this is that the arteries in the penis dilate and the blood can flow into the penis more easily. Another result is that the erectile tissue itself fills with blood. Both of these processes result in an erection. Cialis works by maintaining the level of cGMP in the smooth muscle cells. If you are not mentally sexually aroused, your brain will not stimulate the release of any nitric oxide and you will not produce increased levels of cGMP.