Health Guide delivered to your inbox

You can unsubscribe at any time.
Please review our privacy policy for more info.

Last updated November 22, 2019. 5 minute read

What is horny goat weed? Does it work?

Horny goat weed is reputed to work as an aphrodisiac. Some animal studies show it may have an effect similar to Viagra (sildenafil) and thus might be helpful as an ED treatment. But no clinical studies have been conducted on horny goat weed and ED in humans.

Self Written by Michael Martin
Reviewed by Dr. Mike Bohl, MD, MPH

Horny goat weed is perhaps the most literally named supplement of all time—Chinese farmers noticed that goats seen eating the herb later seemed to be unusually amorous—and it has the reputation of being a bit of a punchline. But enough supplement manufacturers believe in its efficacy that it’s included in dozens of supplements that claim to improve your libido and sexual performance. But does that mean you should too?

Vitals

  • Horny goat weed (Epimedium or yin yang huo) is an herb used in traditional Chinese medicine.
  • It’s reputed to work as an aphrodisiac. Some animal studies show it may have an effect similar to Viagra (sildenafil) and thus might be helpful as an ED treatment.
  • But no clinical studies have been conducted on horny goat weed and ED in humans.
  • Horny goat weed may have other health benefits, including heart and bone health, but the evidence isn’t strong enough to recommend it for those purposes.

What is horny goat weed?

Horny goat weed is a traditional Chinese medicinal herb, also known as epimedium or yin yang huo. It’s derived from a flowering shrub native to China and has been used in traditional Chinese medicine for thousands of years to treat fatigue and low libido.

Today, horny goat weed is most commonly taken as an aphrodisiac. It’s claimed to boost sex drive and improve the quality of erections, among other effects. Horny goat weed is available as a tablet, capsule, tea, or powder. (It might be listed on a label as Epimedium, Epimedium sagittatum, Epimedium grandiflorum or Epimedium koreanum.) Horny goat weed is sold as a supplement on its own, or as part of other supplement formulations (some of the most popular include Enzyte).

Advertisement

Over 500 generic drugs, each $5 per month

Switch to Ro Pharmacy to get your prescriptions filled for just $5 per month each (without insurance).

Learn more

Horny goat weed and ED

Erectile dysfunction (ED) is a sexual dysfunction in which you can’t get an erection that’s firm enough to have satisfying sex. This can include softer erections, erections that don’t last as long, less frequent erections, or a lack of morning erections. Most men have experienced ED at some point in their lives; by age 50, about half of men will.

During an erection, a natural compound known as nitric oxide helps blood vessels to relax and enable blood flow into the penis. In cases of ED, a protein called phosphodiesterase-5 (PDE5) can interfere with that process, preventing blood from staying in the arteries of the penis and producing an erection.

Some anecdotal reports and animal tests suggest that horny goat weed might help address ED by improving erections. Horny goat weed contains icariin, a substance that is a mild inhibitor of PDE5 (Dell’Agli, 2008). Inhibiting PDE5 is how ED medications like Viagra and Cialis work.

Effectiveness of horny goat weed

A 2010 study published in the Journal of Sexual Medicine found that icariin seemed to benefit rats who had damaged blood vessels. Those fed an icariin supplement were better able to synthesize nitric oxide in penile tissue than those fed a placebo (Shindel, 2010).

In a 2007 study, researchers found that older rats fed an icariin extract for ten days had more frequent ejaculations and a shorter latency period between ejaculation (Makarova, 2007).

A number of studies have found that icariin inhibits PE5 in cavernosal smooth muscle, the kind of tissue that fills with blood during an erection (Xin, 2003; Jiang, 2006; Ning, 2006). 

But these studies on the effects of icariin are mostly suggestive; they’ve been conducted on animals and in test tubes. Horny goat weed may not work the same way in the human body. Clinical trials on horny goat weed’s effect on ED in humans haven’t been conducted.

Additional benefits of horny goat weed

Horny goat weed has also reportedly been used as a treatment for the following medical conditions:

  • High blood pressure
  • Atherosclerosis (Fang, 2017)
  • Decreased libido
  • Autoimmune conditions
  • Osteoporosis. One study found that taking horny goat weed for 24 months, plus calcium supplements, decreased bone loss in postmenopausal women better than taking calcium alone
  • Hay fever
  • Fatigue
  • Brain injury (Liu, 2011)
  • Menopausal symptoms. Horny goat weed is believed to act similarly to estrogen. A 2008 study found that postmenopausal women who took horny goat weed extract for six months had lower cholesterol and higher estrogen levels than those who didn’t (Yan, 2008)

Although some studies have been conducted, the National Institutes of Health says that overall, there’s insufficient evidence to determine whether horny goat weed is effective for any of the above conditions, including ED, and that more research is needed (NIH, 2019).

Side effects and potential risks

According to the NIH, horny goat weed is possibly safe when taken by mouth in appropriate doses. Side effects such as upset stomach, dry mouth, nosebleeds, dizziness, and rapid heartbeat have been reported.

But horny goat weed could have adverse effects when taken in conjunction with other medications, supplements, or health conditions.

Don’t take horny goat weed if you have heart disease; it has been reported to cause rapid, irregular heartbeat and excitability. 

Horny goat weed can change hormone levels, so you shouldn’t take it if you have a hormone-sensitive cancer.

Don’t take horny goat weed if you’re on certain medications, including steroids (like cortisone, prednisone, prednisolone, and methylprednisolone); aromatase inhibitors (like as anastrozole, exemestane, and letrozole); blood thinners; and nitroglycerin.

Horny goat weed can also interact with aspirin, birth control pills, antidepressants, and medications for high blood pressure, high cholesterol, thyroid issues, and immune disorders. Talk with your healthcare provider before taking any dietary supplements.