Supplements for Erectile Dysfunction

Are there any supplements that have been shown to help with erectile dysfunction? Fish oil may help rat penises, but remains untested in humans. Observational studies have found an apparent link between vitamin D deficiency and erectile dysfunction, though as pointed out in a skeptical commentary entitled “A bone to pick with vitamin d deficiency and erectile dysfunction,” perhaps low levels of the sunshine vitamin may just be a proxy for limited (outdoor) physical activity. There was one interventional study of vitamin D finding an improvement of erectile function in middle-aged vitamin D deficient men, but there was no control group to rule out the placebo effect or even to document it superior to doing nothing. 
  
Vitamins A, C, and E have also been put to the test, but universally flopped. Niaspan, slow-release niacin (vitamin B3), also failed to improve erectile function compared to placebo. The one vitamin that may show some promise is folate. ED patients given 500 mcg of folic acid a day went from an International Index of Erectile Function score of 6 (“severe” erectile dysfunction) to 14 (mild-to-moderate) within three months. The researchers suspected this was due to the drop in homocysteine levels measured in blood drawn directly from their penises. They concluded all men with ED should be prescribed folic acid, but the study had no control group, so it really can’t establish cause-and-effect. 
 
One of the most popular ingredients in sexual enhancement supplements, and most extensively studied, is ginseng. A meta-analysis of a half dozen randomized controlled trials found that 4 to 12 weeks of 1800 mg to 3000 mg a day of Korean red ginseng significantly improved erectile function compared with placebo. 58% of men experienced an improvement in sexual function compared with 20% of men in the placebo group. This may be due to an improvement in artery function that has been demonstrated three hours after consumption. Of course this is assuming there’s actually ginseng in your quote-unquote “ginseng.” Testing the authenticity of more than 500 commercial ginseng products across a dozen countries in six continents, about a quarter, were found adulterated. 
 
Some natural “so-called aphrodisiacs” are considered too risky. These include yohimbine, Spanish fly, mad honey, and Bufo toad, the latter of which has been banned by the FDA for its potential lethality. Death has also been attributed to yohimbine, though having been purchased online, who knows what was actually in it.