How does Viagra work?

You will realize how Viagra works by understanding the different stages that lead to an erection. An erection is a result of blood flow to the penis that leads to an increase in its length, width and firmness. When you get sexually aroused, the nervous system in the erectile tissue around the penis releases nitric oxide (NO). NO stimulates a messenger cGMP that causes the arteries to dilate enabling blood flow to the penis. Most men experience erection problems due to narrow arteries or fast drainage of blood through the veins. Viagra works by maintaining the level of cGMP enhancing the blood flow.