How does MUSE produce an erection?
When the penis is flaccid (not erect), the flow of blood into the penis is regulated by the contraction of the muscles in the walls of the blood vessels. The medication contained in the MUSE pellet relaxes these muscles and thereby allows more blood to fill the penis so that it becomes firm. When the effect of the medicine wears off, the muscles in the walls of the blood vessels again contract and slow the amount of blood flowing into the penis.