Men who have trouble achieving or sustaining an erection may be suffering from a condition called erectile dysfunction. Viagra is a very popular drug that has been proven to help men overcome this problem. Although the small blue pill may appear to work like magic, we’ll explain the process of how Viagra actually works. The smooth muscle in the penis called the corpus cavernosum contains a type-5 receptor and PDE receptors, which prevent men from achieving an erection. They break down the muscle-relaxing chemicals in the body, causing blood to exit the penis and the muscles to constrict. The penile area also produces CGMP or cyclic guanosine monophosphate, which relaxes the tissue in the area so an erection can occur. However, Viagra blocks the chemical, PDE5, which reverses an erection and enables more blood to remain in the penis. In simpler terms, Viagra stops the compound necessary for obtaining an erection from breaking down. The effects of Viagra are noticed very soon after taking the pill, with the results lasting up to 4 hours afterwards.