Horny Goat Weed for Men and Women: Testosterone, Libido and Maca

Does horny goat weed increase testosterone? In animal and cell studies, its main flavonoid, icariin, raised testosterone: blood testosterone rose in 15-month-old male rats given icariin for 7 days after reproductive damage from a chemotherapy drug, and testosterone output rose in mouse Leydig cells, the cells that make it. The human trials of epimedium extracts, in 100 and 58 women after menopause, measured bone density, bone markers and safety.

Horny goat weed, also called epimedium, is a traditional Chinese herb with a long reputation for vitality and libido. The other question that comes up most is whether it works for women. This guide covers what the research has looked at in men and in women, how it compares and pairs with maca, how much has been studied, how long it takes, and the side effects worth knowing about.

It is educational, not medical advice.

Key Takeaways

• Testosterone: the testosterone research on horny goat weed comes from cell and animal studies, where its main flavonoid, icariin, raised testosterone production.
• Women: the longest human trial was in women after menopause, where an epimedium flavonoid extract helped maintain bone density over 24 months.
• Maca: in a 12-week trial in men, maca improved self-reported sexual desire from week 8 without changing testosterone.
• Amounts studied: extracts giving 60 mg of icariin a day, or 740 mg of a prenylflavonoid extract a day.
• Safety: well tolerated in the trials, but there are reports of liver injury linked to horny goat weed products, so know the warning signs.

What Is Horny Goat Weed?

Horny goat weed is the common name for epimedium, a genus of about 52 species in the barberry family, also known as barrenwort and, in traditional Chinese medicine, yin yang huo. More than 260 compounds have been isolated from it, and the best known are prenylflavonoids such as icariin (Ma et al., 2011).

Icariin is largely converted in the gut before it reaches the blood. In a human trial, icariin was below detection in the blood after women took an epimedium prenylflavonoid extract; its gut metabolites desmethylicaritin, icaritin and icariside II were what reached the blood (Yong et al., 2021). Our epimedium ingredient guide covers the plant and its compounds in detail.

Does Horny Goat Weed Increase Testosterone?

The testosterone research on horny goat weed comes from cell and animal studies:

• In older rats. In 15-month-old male rats whose reproductive system had been damaged with a chemotherapy drug, icariin given for 7 days raised blood testosterone (Zhang and Yang, 2006).
• In testosterone-making cells. In mouse Leydig cells, the cells that make testosterone, icariin increased the enzymes that build testosterone and raised testosterone output (Sun et al., 2022).

Results in animals and cells do not always carry over to people, so read these as early findings rather than a promise. If testosterone is your main interest, our guide to supplements to support testosterone compares the options, and a blood test from your clinician is the only way to know your own level.

Horny Goat Weed for Men

For men, horny goat weed is mostly taken for its traditional use for vitality and libido. It is often sold together with maca, which has its own human research on desire (below). Men who take it daily should know the liver warning signs in the safety section, especially if they also take other supplements or regular medicines.

Horny Goat Weed for Women

Can women take horny goat weed? Women took part in the two best-known human trials of epimedium extracts:

• Bone density over 24 months. 100 women well past menopause with lower than average bone density took an epimedium flavonoid extract (with 60 mg of icariin a day) or placebo. The extract group maintained bone density at the spine and hip, while the placebo group lost about 2 percent, and the extract did not thicken the lining of the womb (Zhang et al., 2007).
• Safety over 6 weeks. 58 healthy women after menopause took 740 mg a day of an epimedium prenylflavonoid extract or placebo. The extract caused no significant side effects, no changes in liver, blood or kidney tests, and raised a marker of bone formation (Yong et al., 2021).

Epimedium's flavonoids are described as phytoestrogens because some act weakly on estrogen receptors. Epimedium does not contain hormones itself. Women with a hormone-sensitive condition, or who are pregnant or breastfeeding, should ask a clinician before taking it.

Horny Goat Weed With Maca

Horny goat weed and maca are often combined, but they are very different plants.

	Horny goat weed (epimedium)	Maca
What it is	Leafy herb in the barberry family	Root vegetable from the Andes
Key compounds	Prenylflavonoids such as icariin	Macamides and glucosinolates
Human research	Bone density and safety in women after menopause	Sexual desire in men; mood and well-being in women after menopause
Testosterone	Raised in cell and animal studies	No change in a 12-week trial in men

• Maca in men. In a 12-week randomized trial, men aged 21 to 56 took 1,500 mg or 3,000 mg of maca a day or placebo. Self-reported sexual desire improved with maca from week 8, and testosterone and estradiol levels did not differ from placebo (Gonzales et al., 2002).
• Maca in women. In a 12-week crossover trial, 14 women after menopause took 3.5 g of maca a day for 6 weeks. Scores for mood symptoms and for sexual concerns improved compared with placebo, with no change in hormone levels (Brooks et al., 2008).

More on maca in our maca root extract guide, and our guide to black vs red vs yellow maca compares the colors.

For each maca trial, the amounts used and safety, see our guide to maca root benefits.

How Much Horny Goat Weed to Take

What was studied	Amount	How long
Epimedium flavonoid extract (bone)	60 mg of icariin a day	24 months
Epimedium prenylflavonoid extract (safety)	740 mg a day	6 weeks
Maca (men)	1,500 or 3,000 mg a day	12 weeks
Maca (women after menopause)	3.5 g a day	6 weeks

Horny goat weed products are labeled in different ways: some state milligrams of extract, some state an icariin percentage. Compare products by what the label states, and follow your label.

When to take it and how long it takes

The studies gave epimedium and maca every day and measured results after 6 weeks to 24 months; the maca trial in men saw changes in desire from week 8. Take it consistently and give it several weeks. If it is part of a combined formula, follow that label: Clarity Capsules are taken as two capsules in the morning.

Horny Goat Weed Side Effects and Safety

In the two trials above, epimedium extracts were well tolerated over 6 weeks and 24 months. Points worth knowing:

• Liver. A 2024 study notes numerous reports of adverse reactions to epimedium, with liver injury the most common (Wang et al., 2024). In a 2025 case report, a 53-year-old man who had taken horny goat weed daily for over a year developed acute liver injury, which improved after he stopped (Shueb, 2025). Stop taking it and see a clinician if you notice unusual tiredness, nausea, dark urine or yellowing of the skin or eyes.
• Hormone-sensitive conditions. Because some of its flavonoids act weakly on estrogen receptors, ask first if you have a hormone-sensitive condition.
• Medicines. Lab research shows effects on blood vessels, so ask your clinician if you take blood pressure medication or any other regular medication.
• Pregnancy and breastfeeding. Check with your healthcare provider first.

Where Clarity Capsules Fit

Our Clarity Capsules are a daily focus formula: per 2-capsule serving, 200 mg epimedium extract and 200 mg maca root extract alongside lion's mane, bacopa, rhodiola and huperzine A, caffeine-free and made with third-party tested ingredients. The label states 200 mg of epimedium extract per serving; take it as directed, two capsules in the morning. Questions are answered on the Clarity FAQ. For other ingredients sometimes linked to testosterone, see do mushrooms affect testosterone levels? For the other ingredients in a focus formula, see our guide to the best supplements for energy and focus. If you are looking at adaptogens more broadly, Forage is our mushroom and adaptogen blend.

Frequently Asked Questions

Does horny goat weed increase testosterone?

Its main flavonoid, icariin, raised testosterone in cell and animal studies. Results in animals and cells do not always carry over to people, so a blood test is the only way to know your own level.

What does horny goat weed do for women?

In women after menopause, an epimedium flavonoid extract with 60 mg of icariin a day helped maintain bone density over 24 months, and a 740 mg extract was well tolerated over 6 weeks.

Can women take horny goat weed?

Women took part in the main human trials. Because some of its flavonoids act weakly on estrogen receptors, check with a clinician first if you are pregnant, breastfeeding or have a hormone-sensitive condition.

Can you take horny goat weed with maca?

They are often combined, and Clarity Capsules contain both. Maca has its own human research: in a 12-week trial in men, it improved self-reported sexual desire without changing testosterone.

How long does it take for horny goat weed to work?

The studies measured results after 6 weeks to 24 months of daily use. Take it consistently for several weeks.

When should I take horny goat weed?

The studies gave it daily. Take it at the same time each day and follow your label; Clarity Capsules are taken in the morning.

What are the side effects of horny goat weed?

It was well tolerated in the trials, but there are reports of liver injury linked to horny goat weed products. Stop and see a clinician if you notice unusual tiredness, nausea, dark urine or yellowing of the skin or eyes.

Is horny goat weed the same as epimedium?

Yes. Horny goat weed is the common name for epimedium, also called yin yang huo or barrenwort.

What is in horny goat weed?

More than 260 compounds have been isolated from epimedium, and the best known are prenylflavonoids such as icariin. Icariin is largely converted in the gut: in a human trial, its metabolites desmethylicaritin, icaritin and icariside II were what reached the blood. Product labels usually state milligrams of extract or an icariin percentage, so compare products by what the label states.

What is horny goat weed used for?

It has a long traditional use in Chinese medicine for vitality and libido, and it is often sold together with maca. In research, the longest human trial gave 100 women after menopause an epimedium flavonoid extract with 60 mg of icariin a day, and they maintained bone density at the spine and hip over 24 months. In Clarity Capsules it is part of a daily focus formula.

Is horny goat weed effective?

It depends on what you take it for. In 100 women after menopause, an epimedium flavonoid extract helped maintain bone density over 24 months while the placebo group lost about 2 percent. For testosterone, icariin raised it in rat and cell studies. Maca, which is often combined with it, improved self-reported sexual desire from week 8 in a 12-week trial in men.

Sources

• Ma H, et al. The genus Epimedium: an ethnopharmacological and phytochemical review. J Ethnopharmacol. 2011. PubMed 21215308
• Zhang ZB, Yang QT. The testosterone mimetic properties of icariin. Asian J Androl. 2006. PubMed 16751992
• Sun J, et al. Icariin promotes mouse Leydig cell testosterone synthesis via the Esr1/Src/Akt/Creb/Sf-1 pathway. Toxicol Appl Pharmacol. 2022. PubMed 35259346
• Zhang G, et al. 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. J Bone Miner Res. 2007. PubMed 17419678
• Yong EL, et al. Randomized, double-blind, placebo-controlled trial to examine the safety, pharmacokinetics and effects of Epimedium prenylflavonoids, on bone specific alkaline phosphatase and the osteoclast adaptor protein TRAF6 in post-menopausal women. Phytomedicine. 2021. PubMed 34352588
• Gonzales GF, et al. Effect of Lepidium meyenii (maca) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men. Andrologia. 2002. PubMed 12472620
• Brooks NA, et al. Beneficial effects of Lepidium meyenii (maca) on psychological symptoms and measures of sexual dysfunction in postmenopausal women are not related to estrogen or androgen content. Menopause. 2008. PubMed 18784609
• Wang J, et al. Integrating metabolomics and bioinformatics to reveal the mechanism of Epimedium-induced liver injury. Biomed Chromatogr. 2024. PubMed 38981997
• Shueb M. Herb-induced liver injury: a case of acute hepatotoxicity associated with horny goat weed use. Spartan Med Res J. 2025. PMC12459906

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.