Does Horny Goat Weed Actually Boost Testosterone? The Truth Might Surprise You

Last updated on October 7, 2025

Horny Goat Weed is well known for helping to assist in sexual performance. But does it work as a “natural testosterone booster”? Testosterone is important to sex, but far from the only thing.

So, I dove deep into research, and what I found was a bit frustrating. If you’re thinking about trying Horny Goat Weed (Epimedium sp.) to boost your testosterone, you deserve to know what the science actually says – not just what supplement companies want you to believe.

The Legend Behind the Name

First, let’s talk about how this herb got its provocative name. According to Chinese folklore, a goat herder noticed his flock becoming unusually frisky and energetic after grazing on a particular plant. The herder tried the plant himself and experienced similar effects.

In Traditional Chinese Medicine, it’s called “Yin Yang Huo,” which translates roughly to “licentious goat plant.” For over 2,000 years, Chinese practitioners have used it to support kidney yang energy – essentially what we might call vitality and action in the body. This is how Epimedium (the Latin genus name) became known as “Horny Goat Weed” in the West.

What I Expected to Find vs. What I Actually Found

When I started researching this topic, I expected to find at least some human studies showing testosterone increases. After all, dozens of supplement companies market Horny Goat Weed as a “proven testosterone booster.” What I discovered instead was a perfect example of how marketing claims can run far ahead of actual science.

Here’s the reality: there are no published human studies showing that Horny Goat Weed increases testosterone levels. Zero. The human studies that do exist look at some other thing but they don’t measure testosterone in men. This was honestly surprising to me, given how confidently this herb is marketed for testosterone support.

But just because there is no scientific evidence, doesn’t mean it doesn’t support this. Lack of evidence is not the same as evidence of lack. Let’s explore what is there to get a complete picture.

The Animal Studies That Started It All

Where did these testosterone claims come from? The answer lies in animal research, and this is where things get interesting – and a bit complicated.

Several studies in rats have shown that icariin, the so-called main active compound in Horny Goat Weed, can influence testosterone production under certain conditions. For example, one Chinese study found that moderate doses of icariin increased testosterone and in adult male rats that were poisoned over seven days.

Other researchers discovered that icariin upregulated genes involved in testosterone synthesis, particularly in the Leydig cells of the testes. Here icariin was protective against anti-androgenic phthalates (more examples of my Herbal Armor hypothesis).

But here’s the catch – and it’s a big one. The doses used in these and more rat studies translate to incredibly high amounts for humans. We’re talking about doses that would be impractical and potentially unsafe for people to take. Even more problematic, research shows that icariin is poorly absorbed in humans, meaning even if you took those massive doses, your body wouldn’t absorb much of the active compound, with much of it being converted into other compounds within the gut.

Another bit of interesting research wrote, “It is implied that regardless of its effects on serum T, ICA does not impact pituitary LH expression. It is possible that ICA may influence aromatase or 5-alpha reductase activity in vivo and thereby modulate serum T levels without directly impacting LH secretion.” In other words, the study found that ICA (aka Icariin) did not directly increase testosterone synthesis but may have increased testosterone levels by reducing its conversion to DHT.

So this research is mixed. That last one also saw more results with lower rather than larger doses.

Human Trials but Not Quite on Testosterone for Men

I found two human trials for men using Horny Goat Weed. Unfortunately, these exclusively included Horny Goat Weed in formulas, not on its own.

In one study a formula featuring Horny Goat Weed along with Deer Antler, Cynomorium songaricum, Safflower and Cistanche deserticola, helped with erectile function. Testosterone was not measured.

In another study the formula contained Horny Goat Weed as well as Aged Garlic Extract, Ginseng, Oriental Bezoar, Velvet Antler, and Cuscuta Seed. Here, testosterone was measured in some participants, but there was no increase. Despite that, the participants scored better on aging and sexual function questionnaires after taking the formula for 6 months.

Those were the only two human trials on men I could find. But wait, were some on women…

These studies tend to focus on bone health of menopausal and post-menopausal women, which is arguably the second most researched benefit of Horny Goat Weed–after its effects on sexual function. In these trials, Horny Goat Weed was used by itself, not in formula.

In a study with 90 postmenopausal women over six weeks, hot water extract of Epimedium raised estradiol (estrogen) levels but not that of testosterone or progesterone.

To contrast that, in a two year placebo-controlled trial, while Horny Goat Weed was suggested to help support bone strength, it did not change estrogen levels. This trial did not look at testosterone. (More about Osteoporosis here.)

So, as you see there isn’t any quantifiable data regarding Horny Goat Weed supporting the body’s ability to increase testosterone. In the very limited places it was looked at, it did not have an effect.

How Horny Goat Weed Actually Works

This is where the story gets more nuanced and actually more interesting. While Horny Goat Weed may not boost testosterone, it does seem to affect male physiology in other ways.

The primary mechanism appears to be PDE5 inhibition, which is very important for erectile function. This is the same pathway by which synthetic single target solutions exist (that we’re not supposed to name on this website). Icariin helps increase nitric oxide production, which improves blood flow throughout the body, including to the reproductive organs. Furthermore, by limiting PDE5 it stops NO and cGMP’s breakdown. This can genuinely improve erectile function even without changing hormone levels.

What is very fascinating is that icariin and it’s related compounds are phytoestrogens. Many men get scared of these because they think they’ll lead to feminizing effects. And while that is possible with too much (like soy milk given to infants!) the truth is more complicated. Clearly, these phytoestrogens can be very potent and helpful to men.

There seems to be other action as far as increasing desire as well. How that works has not been figured out. My hypothesis is that these compounds may also be active in the nervous system. Estrogen plays a role in brain health, including sexual desire for men, so feasibly these phytoestrogens could be working through similar receptors.

Think of it this way: if you feel more confident about your performance, your blood flow is improved, you even feel more desire, that could all be true even if your testosterone levels haven’t budged.

From a Traditional Chinese Medicine standpoint, Horny Goat Weed is classified as a yang tonic – it’s warming, ascending, and supports what TCM calls “kidney yang deficiency.” In practical terms, this might manifest as feeling cold, fatigued, or lacking drive. While exploring the biological mechanisms is useful, so too is this energetic perspective.

Real-World Effects People Report

Even though the testosterone claims aren’t supported by research, many men do report positive effects from Horny Goat Weed. The most common experiences include improved desire, better mood, and sometimes enhanced exercise performance. These effects likely come from the improved circulation and mild stimulant properties rather than hormonal changes.

Here are just a few reviews from our 10:1 :

• “Moby is up and coming! The best bang for the buck! Thank you!!” – Gregory Morse
• “Quite possibly my favorite herb. I take it every Saturday.” – Mark D.
• “Just remember quality isn’t cheap. This product is amazing.” – Richard Lewis

Safety Considerations You Should Know

Before we go further, let’s talk about safety, because this is where things get serious. Horny Goat Weed isn’t just a harmless plant – it can have real effects on your cardiovascular system and can interact with medications.

The herb can lower blood pressure, which means it can be dangerous if you’re already taking blood pressure medications or have cardiovascular issues. There have been case reports of people experiencing rapid heartbeat, mood changes, and even manic-type symptoms from Horny Goat Weed use.

But that’s all pretty rare. Most research reports zero to mild side effects. Still, you should be aware before trying it.

If you’re taking any medications – especially blood thinners, blood pressure drugs, or heart medications – you need to talk to your healthcare provider before trying this herb.

When Horny Goat Weed Might Make Sense

Despite the lack of testosterone research, there are situations where Horny Goat Weed is definitely worth considering. If you’re dealing with poor circulation, low desire that seems related to blood flow issues, or what Traditional Chinese Medicine would call “kidney yang deficiency” symptoms, it might provide some benefit.

If your testosterone is great, but you’re still having some issues, this could be an even better fit.

And, of course, women can use it for similar sexual effects as well as the more researched bone health supporting purposes.

Better Options for Actually Supporting Testosterone

If your real goal is supporting healthy testosterone levels, there are better-researched options available. Ashwagandha has shown genuine testosterone increases in human studies, particularly in men under stress or engaging in resistance training. 

Tongkat Ali also has human research supporting its use for testosterone support, especially in older men with low-normal levels.

We’ve recently even provided new research that Pine Pollen can help support the body with either free testosterone or total testosterone, along with several markers of sexual health and overall quality of life.

In addition to herbal support, the most effective approaches for optimizing testosterone are still lifestyle-based. This includes resistance training, adequate sleep, maintaining a healthy body weight, managing stress, and ensuring you’re getting enough critical nutrients such as vitamin D and zinc.

My Bottom Line

After diving deep into the research and traditional uses, here’s my honest assessment: Horny Goat Weed is not the testosterone booster it’s marketed to be. The claims are based on animal studies that don’t translate well to humans, and no human research has confirmed testosterone increases. I’m not saying that’s impossible, but I don’t think it is the primary way it works.

However, that doesn’t mean it’s worthless. Far from it. It is one of the best for sexual benefits that many men associated with testosterone. Biology is complex so it’s not as simple as many think it to be. For some men, particularly those dealing with circulation issues or low libido, it might provide genuine benefits through its PDE5 inhibition and more

The most important thing is being honest about what the research shows versus what marketing claims suggest. In a world full of overblown supplement promises, sometimes the most powerful thing we can do is tell the truth about what actually is proven and what is not.

Related Articles:

• Do Testosterone Boosting Supplements Actually Work?
• Does Cistanche Increase Testosterone? A Deep Dive into the Science & Benefits
• Which is More Important: Total Testosterone or Free Testosterone?
• Nitric Oxide in Cistanche and Horny Goat Weed

This information is for educational purposes only and has not been evaluated by the FDA. Always consult with a qualified healthcare practitioner before beginning any herbal regimen, especially if you have medical conditions or take medications.