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Horny Goat Weed and ED: Here’s the Deal

Mary Lucas, RN

Medically reviewed by Mary Lucas, RN

Written by Our Editorial Team

Last updated 2/1/2022

Erectile dysfunction (ED) is a common sexual health issue that can occur in men of all ages and backgrounds. It can be a either short or long-term issue that affects your sexual satisfaction and general quality of life.

If you’re one of the millions of guys affected by erectile dysfunction, you’ve probably looked into treatment options such as Viagra®.

You may have also heard of natural supplements that claim to increase blood flow and improve erections, such as epimedium, or horny goat weed.

While horny goat weed sure sounds like it’s going to help you in the bedroom, putting something into your body based solely on its name probably isn’t the best move. 

When it comes to supplements and natural remedies for ED, weeding through the huge amount of information (and misinformation) online is hard work. A good first step: trust those who share the evidence and back claims with scientific research.

We did our best to round up some facts on this largely mysterious supplement and its potential effects on erections and sexual performance. Here’s the short version:

TL;DR: What You Need to Know About Horny Goat Weed

  • Horny goat weed is an informal name that’s used to refer to various herb species of the Epimedium genus. These herb species have been used in traditional Chinese medicine for centuries and are sometimes referred to as "yin yang huo."

  • Like with other herbal supplements, there’s limited evidence that horny goat weed offers any health benefits. Most of the research on this herb has been performed in labs under a microscope, not on humans.

  • Some research on animals suggests that icariin, a component in horny goat weed, might have positive effects on blood flow to the penis by inhibiting the effects of PDE5.

  • However, only a small amount of research compares horny goat weed to existing PDE5 inhibitors such as sildenafil. In one study, researchers discovered that horny goat weed is about 1/80th as effective as prescription ED drugs.

  • Much more research on horny goat weed is needed before we can confidently state that it’s a worthwhile treatment for erectile dysfunction.

What Is Horny Goat Weed?

Epimedium grandiflorum, or horny goat weed, is a plant that’s native to China and Korea, but is now found throughout the world. Its unique name can be traced back to a Chinese goat herder, who reportedly noticed increased sexual activiity in his herd after they ate its leaves.

The name “horny goat weed” is a translation of the Chinese version, “yin yang huo,” as the herb has long been used in traditional Chinese medicine (TCM).

Horny goat weed has been used as an ingredient in traditional Chinese medicine for more than 1,000 years. It’s generally considered a yang tonic that enhances the “energetic organ” (kidney) and promotes fertility and sexual function.

Horny goat weed is one of the most common ingredients in natural remedies for various sexual performance issues, including ED. It’s easy to find in supplements marketed as aphrodisiacs or sexual performance enhancers. 

As is common with herbal supplements, many of these products contain horny goat weed and a mix of other ingredients, such as maca and ginseng. 

Supplements like these are not regulated by the Food and Drug Administration in the same way that prescription drugs are. This means they aren’t required to be as rigorously tested for safety or backed up by solid proof of effectiveness.

It also means that you’re likely to get varying amounts of active ingredients from supplement to supplement. 

Understanding Erectile Dysfunction

Before we get into the specifics of horny goat weed, it’s important to explain the basics of how and why erectile dysfunction occurs in the first place.

Erections depend on a combination of proper nerve function and healthy blood flow. When you feel sexually aroused, nerves in your brain and the areas that surround your penis promote the relaxation of the muscles inside your penis, called the corpora cavernosa.

The corpora cavernosa are two masses of erectile tissue inside your penis. As they relax, blood flows into the tissue, causing your penis to become larger and firmer. This is what gives you the firm erection that’s needed for penetrative sex.

As blood flows into the erectile tissue of your penis, a fibrous sheath called the tunica albuginea traps this blood, helping you to sustain the erection during sexual activity.

When you reach orgasm and ejaculate, the same process occurs in reverse, with blood flowing out from the corpora cavernosa and your penis becoming smaller and less rigid.

One natural chemical that’s involved in this process is an enzyme called phosphodiesterase-5, or PDE5.

PDE5 is found inside the smooth muscle cells of your blood vessels. It plays a key role in the control of blood flow. When the effects of PDE5 are inhibited, your blood vessels can dilate and blood can more easily flow to certain parts of your body, including your penis.

Medications for erectile dysfunction, such as sildenafil (the active ingredient in Viagra), tadalafil (Cialis®), vardenafil (Levitra®) and avanafil (Stendra®) belong to a class of drugs referred to as PDE5 inhibitors.

These medications work by reducing the effects of PDE5 and making it easier for blood to flow into your penis when you’re sexually aroused. 

You can learn more about this process, as well as the options available for improving blood flow to the penis, in our guide to the most common ED treatments and drugs

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Horny Goat Weed Medicinal Uses

In traditional Chinese medicine, epimedium has historically been used to treat cardiovascular health issues, including those that affect the circulatory system.

Proponents of horny goat weed typically point to its active ingredient, icariin, as a source of its potential benefits. Some research suggests that icariin might inhibit the effects of PDE5 and improve blood flow to certain parts of the body, including the penis.

It’s important to point out that most of the existing scientific research on horny goat weed has been carried out in a lab setting, usually under a microscope. A few studies have looked at its effects in animals, but human research is very limited. 

This research has found that icariin, the active ingredient in horny goat weed, may have some anti-inflammatory, antiosteoporotic and neuroprotective properties, meaning it may be effective at reducing inflammation, promoting strong bones and protecting the brain. 

However, studies have also found that icariin has quite poor absorption and oral bioavailability, meaning only a small amount actually reaches the bloodstream and provides any effects.

When it comes to research involving humans, there isn’t very much to support horny goat weed as a treatment for any real diseases or health conditions. 

However, a few studies have produced interesting findings. One human study involving elderly patients with vascular disease affecting blood flow to the heart and brain found improved blood circulation for those patients who were given epimedium compared to those who were not.

The researchers note they believe these results were due to epimedium’s ability to lower blood lipid levels and its effects on platelets and clotting. It was also noted to be rich in antioxidants.

A double-blind, placebo-controlled study published in the Journal of Bone and Mineral Research in 2007 involving 100 post-menopausal women also found compounds derived from epimedium to prevent bone loss over a 24 month period.

Horny Goat Weed for Erectile Dysfunction

Even though horny goat weed is one of the most popular ingredients in over-the-counter sexual health supplements, there’s very little high quality research showing that it treats ED.

A few animal studies have supported the theory that horny goat weed helps to improve erectile function by inhibiting PDE5, but more research is needed to confirm this hypothesis.

In 2013, a double-blind, placebo-controlled study published in the African Journal of Traditional, Complementary and Alternative Medicines found that a supplement containing epimedium had positive effects on men’s erections and sexual performance. 

However, the supplement used in this study also contained maca and several other ingredients, making it impossible to know whether the benefits were caused by horny goat weed, by another ingredient or by a combination of active ingredients. 

Other research has found that icariin, the active ingredient in horny goat weed, appears to treat erectile dysfunction in rats.

This research is interesting, and certainly promising. However, it’s important to keep in mind that substances that are effective at treating ED or another medical condition in animals don’t always have the same benefits in humans. 

It’s also important to keep in mind that the anecdotal reports you can often find in blog posts and online reviews of horny goat weed don’t necessarily mean that it’s an effective option for treating ED or improving blood flow. 

In other words, we need more studies -- and more importantly, higher quality research -- before we can confidently say that horny goat weed offers any serious benefits for erectile dysfunction or other male sexual performance issues. 

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Horny Goat Weed Side Effects and Safety

Like other supplements, horny goat weed may cause side effects. Reported adverse effects of horny goat weed extract and its active ingredients include:

  • Nausea

  • Dizziness

  • Vomiting

  • Irregular heartbeat

  • Irritability

  • Fast, increased speech

Currently, there are no long-term toxicity studies that look at the safety of horny goat weed or its active ingredient icariin. However, research suggests that some horny goat weed extracts can be safely used for several months at a time without significant issues.

In some cases, it may not be safe to take horny goat weed. For example, horny goat weed may slow blood clotting, meaning it may worsen bleeding disorders or contribute to an increased risk of bleeding during surgery.

Because horny goat weed acts like estrogen in the body, it may affect estrogen levels and play a role in the development of estrogen-sensitive conditions, such as breast and uterine cancer.

There have also been isolated reports of cardiovascular issues, such as tachyarrhythmia (overly fast heart rate) in people who use horny goat weed supplements. 

Because of these safety concerns, it’s important to talk to your healthcare provider before using horny goat weed or any other sexual health supplements. 

This conversation is particularly important if you already use prescription medication, or if you’ve been diagnosed with a health condition such as cardiovascular disease.

Horny Goat Weed Interactions

Research suggests that horny goat weed may interact with some medications and supplements, including those that are broken down by the liver.

Horny goat weed may affect how quickly the liver is able to metabolize some medications, such as those targeted by enzymes CYP1A2 and CYP2B6. This could cause these medications to produce different effects and/or side effects.

Because of its effects on blood clotting, horny goat weed may also interact with anticoagulants and antiplatelet medications, contributing to an elevated risk of bleeding and/or bruising.

Some supplements that affect blood clotting, such as ginger, ginkgo, garlic, Panax ginseng and nattokinase, may also be affected by horny goat weed. 

Horny goat weed may slow down the absorption and processing of caffeine, causing you to feel the effects of caffeine from coffee, tea, energy drinks or other products for longer or at a greater intensity level. Horny goat weed may also interact with drugs that contain estrogen.

Finally, horny goat weed may interact with medications and supplements that reduce your blood pressure levels, causing a more significant reduction in blood pressure. 

To avoid interactions, make sure to inform your healthcare provider about any supplements and medications you currently use or have recently used before taking horny goat weed.

Is Horny Goat Weed Effective?

Despite its popularity as a natural remedy for everything from brittle bones to erectile ED, there isn’t very much evidence to suggest that horny goat weed is effective. 

In general, research into horny goat weed’s effects is limited, both in quantity and quality. There are few studies available that look at its effects, with the tiny amount of research that’s available largely limited to studies of lab rats. 

This doesn’t necessarily mean that horny goat weed isn’t effective. Instead, it largely means that we don’t yet know whether it’s effective or not. 

Put simply, the jury is still out on horny goat weed. As more research is carried out, we’ll find out more about horny goat weed’s effectiveness, or lack thereof, as a potential treatment for erectile dysfunction and other sexual health issues. 

Other Treatments for Erectile Dysfunction

While research is limited on the effects of horny goat weed, there are a few existing treatments for erectile dysfunction that are backed up by real evidence.

Of these, the most popular are oral PDE5 inhibitors, which work by increasing blood flow to the penis. These come in tablet form and are designed for use around one hour before you plan to have sex, making them a convenient, easy-to-use choice for treating ED.

The most popular PDE5 inhibitors are:

  • Sildenafil. The active ingredient in Viagra, sildenafil typically works in 30 minutes to an hour and provides relief from ED for up to four hours per dose.

  • Tadalafil. The active ingredient in Cialis, tadalafil is a longer-lasting ED medication that can provide relief from ED symptoms for up to 36 hours per dose.

  • Vardenafil. The active ingredient in Levitra, vardenafil is similar to sildenafil and is used to treat ED for four to five hours per dose.

  • Avanafil. Available as Stendra®, this is a fast-acting ED medication that works in 15 to 30 minutes and is less likely to cause certain side effects. 

We offer several FDA-approved ED medications online, following a consultation with a licensed healthcare provider who will determine if a prescription is appropriate. 

Other options for treating ED include therapy (when ED is caused by a psychological issue) and lifestyle changes such as keeping yourself active, improving your diet and limiting harmful habits such as smoking and alcohol consumption. 

We’ve talked about these techniques more in our detailed guide to the best ways to protect your erections naturally

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Learn More About Treating ED

Erectile dysfunction is a frustrating issue that can develop at any time in your life, from your 20s or 30s to middle age.

Although there isn’t much evidence that horny goat weed is an effective treatment for ED, there are options available if you find it difficult to get or maintain an erection firm enough to have sex with your partner. 

Our guide to the causes of ED goes into more detail about how ED can develop, as well as the steps that you can take to improve your erections and sexual performance.

If you’re worried that you might have ED, you can access effective ED medication online after a consultation with a licensed healthcare provider. 

10 Sources

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references.

  1. Horny Goat Weed. (2021, August 26). Retrieved from https://medlineplus.gov/druginfo/natural/699.html
  2. Dell’Agli, M., et al. (2008, September). Potent inhibition of human phosphodiesterase-5 by icariin derivatives. Journal of Natural Products. 71 (9), 1513-7. Retrieved from https://pubmed.ncbi.nlm.nih.gov/18778098/
  3. Corazza, O., et al. (2014). Sexual Enhancement Products for Sale Online: Raising Awareness of the Psychoactive Effects of Yohimbine, Maca, Horny Goat Weed, and Ginkgo biloba. BioMed Research International. 841798. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4082836/
  4. Horny Goat Weed. (2015, June 5). Retrieved from https://wa.kaiserpermanente.org/kbase/topic.jhtml?docId=hn-4391000
  5. FDA 101: Dietary Supplements. (2015, July 15). Retrieved from https://www.fda.gov/consumers/consumer-updates/fda-101-dietary-supplements
  6. Erection Ejaculation: How It Occurs. (2020, November 27). Retrieved from https://my.clevelandclinic.org/health/articles/10036-erection-ejaculation-how-it-occurs
  7. Dhaliwal, A. & Gupta, M. (2021, June 25). PDE5 Inhibitors. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK549843/
  8. Tan, X. & Weng, W. (1998). Efficacy of epimedium compound pills in the treatment of the aged patients with kidney deficiency syndrome of ischemic cardio-cerebral vascular diseases. Bulletin of Hunan Medical University. 23 (5), 450-2. Retrieved from https://pubmed.ncbi.nlm.nih.gov/10682558/
  9. Zhang, G., Qin, L. & Shi, Y. (2007, July). Epimedium-derived phytoestrogen flavonoids exert beneficial effect on preventing bone loss in late postmenopausal women: a 24-month randomized, double-blind and placebo-controlled trial. Journal of Bone and Mineral Research. 22 (7), 1072-9. Retrieved from https://pubmed.ncbi.nlm.nih.gov/17419678/
  10. Punyawudho, B., Puttilerpong, C., Wirotsaengthong, S. & Aramwit, P. (2013). A Randomized, Double-Blind, Placebo-Controlled Crossover Study of Cappra® for the Treatment of Mild or Mild to Moderate Erectile Dysfunction in Thai Male. African Journal of Traditional, Complementary and Alternative Medicines. 10 (2), 310–315. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3746578/

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.