What is the mechanism behind it?
When the nerves in your penis are stimulated, you get an erection. As a result, the muscles surrounding the corpus cavernosa, which are two cylinder-shaped chambers of spongy material along your penis, relax and allow blood to flow in, causing an erection.
When you take Generic Viagra, the walls of your blood vessels relax, allowing more blood to flow into the parts of your penis that cause an erection.
Your nerves don’t communicate with your brain properly, and blood doesn’t flow properly into the corpus cavernosa when you have ED.