Buy Viagra, which contains the active ingredient sildenafil, is one of the most widely used medications for treating erectile dysfunction (ED), with millions of users in the United States alone and many more globally.

Sildenafil belongs to a class of drugs known as PDE5 inhibitors. It works by inhibiting the effects of an enzyme known as phosphodiesterase type 5, or PDE5, which regulates blood flow to the penis.