The Science: Some studies have implied that feeding maca to domestic cattle increases sperm production, but there is very little data about any sexual effect on humans. One very small randomized double-bind trial of men with erectile dysfunction found that men taking maca extract reported a small increase in their ability to get erections. But so did the control group. As with the fenugreek study, a similar study with a larger group of people is needed to see whether any differences between the controls and the maca-eaters are real.
Research is mixed on the effectiveness of acupuncture as an erectile dysfunction cure, but one study published in November 2013 in the Journal of Alternative and Complementary Medicine found that acupuncture can be beneficial for men experiencing erectile dysfunction as a side effect of antidepressants, including selective serotonin reuptake inhibitors (SSRIs) and serotonin noradrenaline reuptake inhibitors (SNRIs).
The Claim: If you squint and have an excellent imagination, mature ginseng roots vaguely resemble a human body. That ties into folk ideas for finding medicines–in this case, the idea that a plant that looks like a person must contain materials that help sick people. Ginseng was traditionally used as a tonic to treat erectile dysfunction and low sexual drive in men (as well as many other complaints).
Many products contain undocumented “fillers” that can cause allergic reactions. In recent years, the FDA has found over 300 herbal products that contain hidden, deceptively labeled, or dangerous ingredients4. And since 2015, the FDA has released public warnings on more than 160 ED supplements and “male enhancement” products found to contain dangerous ingredients and contaminants5 . An independent study of FDA data, conducted in 2018, found almost 800 herbal supplements that contained unlisted ingredients6.
Yohimbe A number of clinical trials have shown that the primary component of this bark from an African tree can improve sexual dysfunction associated with selective-serotonin reuptake inhibitors (SSRIs) used to treat depression. This herb has been linked to a number of side effects, including increased blood pressure, fast or irregular heartbeat, and anxiety. Yohimbe shouldn't be used without a doctor's supervision.