Apparently, not much according to a  recent article written by the American College of Physicians that said all three of the medications preformed well in combating ED, and there is not sufficient evidence to recommend one drug over another.

“The evidence is insufficient to compare the efficacy and adverse effects” of the drugs because “few head-to-head trials are available,” the guidelines say. This lack of evidence comparing one drug against another is familiar. Companies often launch studies comparing new drugs to placebos, rather than to existing drugs; without head-to-head trials, it can be tough to know how competing drugs stack up.

A report by the WSJ has said that since there is not sufficient evidence of one ED drug being more affective than another, most doctors are prescribing brands based on price.

According to our database, Viagra comes in first with the cheapest price per pill at $1.60, followed by Cialis at $1.90 per pill, and Levitra at $2.23 per pill.

So when you go to talk to your doctor about beginning a treatment for ED remember: All the major brands will work with the same efficacy, so get your prescription for the cheapest one.