Horny Goat Weed: Benefits, Side Effects, Best Time to Take It & More

Horny Goat Weed

(Epimedium, Barrenwort, Icariin)

Evidence: Reasonable
Possible Benefits: Low
Safety: Reasonable

What is horny goat weed?

Epimedium, also known as barrenwort or horny goat weed, is an adaptogenic herb with a long history of use as a traditional medicine. This herb is often used as a supplement for its aphrodisiac properties. This article is about the main benefits of horny goat weed, its potential side effects, the best time to take it, and more.

Possible benefits

All of the potential benefits mentioned below are dose-dependent. As with other adaptogenic herbs, there is a sweet-spot dose that allows you to get most of the benefits without causing meaningful side effects or tolerance buildup in the body. We will discuss the best dosing protocol later in this article.

Major benefits

Increased libido – Horny goat weed can significantly increase sex drive and erections in men. This is because icariin, the main bioactive compound in this herb, can inhibit the PDE5 enzyme and promote nitric oxide signaling.

Minor benefits

Increased bone mineral density – The rate of bone loss was reduced in people who took the supplement for 2 years but only to a small degree.
Increased testosterone – Testosterone-boosting effects were shown in rats that took 200mg/kg of an extract standardized for 40% icariin. This would translate to about 6 mg per pound of body weight, which would be about 1000 mg for an average, 170 lb adult. These amounts are very high and usually not recommended as we don’t yet know if they are safe in the long term. More human research is needed to confirm or disprove this effect.

Possible side effects

The side effects below are dose-dependent. The risk for them increases (often linearly but sometimes exponentially) as you increase the dose. Some of the side effects only apply to very high doses.

Initial adverse reaction – Like other adaptogens and hormetic stressors, horny goat weed can worsen some aspects of your health and even make you sick for a few days after you start taking it. While this can be unpleasant, it is usually a sign that the supplement is working and creating a hormetic response that allows the body to adapt and become more resilient in the long term.
Nausea – This side effect is most common when people take the herb on an empty stomach.
Diarrhea – You can usually prevent diarrhea or stomach discomfort by taking this herb with a meal.
Toxicity – As an adaptogen, horny goat weed acts as a mild stressor on the body. That is usually a great thing as it allows your body to adapt to specific forms of stress and become more resilient. However, stressing the body too much can be counter-productive and cause multiple side effects, including toxicity. While acute toxicity is extremely rare, taking very high amounts of this herb could lead to chronic toxicity and cause health problems over time. To prevent chronic toxicity or the buildup of tolerance, staying below 5 grams of dry herb or 200 mg of icariin a day is best unless you have a great reason to take more.
Contamination – If growing or storing conditions are not adequately controlled, horny goat weed can be contaminated with bacteria, molds, and other potentially harmful microorganisms. Some growers also use pesticides and herbicides, some of which are unsafe. Another issue is that herbal supplements can get contaminated with other supplements and chemicals during the manufacturing process. Choose the brand you get herbs and herbal supplements from wisely. It is often best to use websites like Amazon, where thousands of users have reviewed and rated the products. You are less likely to buy something of lower quality there.

Who should not take horny goat weed?

You should probably avoid taking horny goat weed if you:

are allergic to this herb
experience a severe adverse reaction after taking the herb (though a mild adverse reaction is usually a great thing as it is a sign that the supplement is working and causing a hormetic response that allows the body to adapt and become more resilient)
are pregnant or breastfeeding (while it can be safe to take this adaptogen during pregnancy or breastfeeding, it acts as a mild stressor and can cause some unnecessary risk to the child)
suffer from an autoimmune disease (adaptogenic herbs can stimulate the immune system, which can worsen symptoms of autoimmune diseases, such as lupus or multiple sclerosis)

Who will benefit the most?

You should consider taking the supplement if you:

wish to boost your libido and sex drive

How much horny goat weed should you take?

Because horny goat weed is an adaptogenic herb, it acts as a mild hormetic stressor on the body, which allows your body to adapt and become more resilient to certain kinds of stressors in the long term.

A higher dose does not necessarily lead to more pronounced benefits. Instead, there appears to be an inverted U-shaped dose-response pattern. In other words, you want to find a sweet-spot dose that allows you to get the benefits of horny goat weed without putting too much stress on the body or quickly causing the body to develop tolerance to the herb.

Testosterone-boosting effects were shown in rats that took 200mg/kg of an extract standardized for 40% icariin. This would translate to about 6 mg per pound of body weight, which would be about 1000 mg for an average, 170 lb adult. These amounts are very high and usually not recommended as we don’t yet know if they are safe in the long term.

Studies done on humans use much lower doses, typically anywhere from 10-200 mg of icariin.

The sweet-spot dose is typically somewhere around 5 grams of dry herb daily. If you buy an x:1 extract, divide the dry herb dosage by x. If you buy an extract standardized for icariin, the sweet spot is about 60-150 mg of icariin.

The higher end of this range usually provides slightly more benefits in the short term. If you plan to take this herb for a longer time (multiple months or years), the lower end is probably a better way to go since you would develop tolerance faster if you were to take higher doses.

While higher doses are generally safe, taking more than the sweet-spot dose daily would be counter-productive as your body would quickly develop tolerance.

Additionally, very high doses can put too much stress on your system and cause health problems if you take the supplement for a prolonged period.

While this herb could theoretically cause acute toxicity, you would need to take an extremely high dose that is way beyond what is generally found in even the most potent supplements.

Like with most other adaptogens, it is best to cycle horny goat weed and take about 2 days off every week to reset your tolerance. This will allow you to keep getting the benefits in the long term.

Keep in mind that the effects of this herb are cumulative. Therefore, you must take it for at least 2-4 weeks to notice the benefits. But again, cycling the herb and not taking it at least twice a week is necessary to prevent tolerance in the long term.

Best time to take horny goat weed

You can take this herb with or without food. Each of these options has its benefits. The main bioactive compounds in the herb should absorb well either way.

If you experience nausea or stomach discomfort when you take this herb, taking it with food should prevent these unpleasant effects or at least make them less intense.

If you take this herb on an empty stomach, the short-term effects will kick in faster and they will be more pronounced but will not last as long.

Whether you take this herb in the morning or the evening typically does not make much difference. Both options are fine so feel free to experiment.

Interactions

Yohimbine
These two herbs have similar aphrodisiac effects achieved by similar mechanisms (mainly by inhibiting the PDE5 enzyme). Their effects can be additive when you take them together.

Where to buy horny goat weed?

Amazon is the best option for ordering horny goat weed and other herbal supplements in most countries. They offer some very affordable products backed by many positive reviews. Also, you can choose from a wide range of brands without having to search through other markets on the internet.

Some brands display the dosage per serving instead of per pill or capsule. Therefore, you may accidentally buy something less potent than you intended. Do not fall for this marketing trick.

FAQ

As with most other herbs and herbal supplements, it is best to cycle horny goat weed and stay off of it for about 2 days per week to reset your tolerance back to baseline. This will keep your body sensitive to the herb and allow you to keep getting the benefits in the long term.

When you take an extract standardized for icariin, you know exactly how potent it is and how much you need to take to get the desired outcome. Herbal extracts also tend to be cheaper than unextracted powders in many cases. However, many of the potentially beneficial compounds get lost during the extraction process. Therefore, if you know how potent the unextracted powder is, it is almost always a better option.

All of these options are fine. The two most important things to consider are the price and dosing. Powders are almost always the cheapest form. However, you may need a highly accurate scale to dose them correctly (preferably 0.001g). You can get one for as little as $20 from Amazon. Dosing the powders also takes some time that can add up over months or years. The disadvantage of capsules is that they are often made of bovine gelatine, which rarely comes from ethical sources.

Yes, you can. This herb should not impact your sleep in any negative way. Whether you take it in the morning or the evening typically doesn’t make much of a difference. Both options are fine so feel free to experiment.

This herb should not become harmful once it exceeds the expiration date but it can lose potency over time. Keep the herb or the herbal supplement in a cold, dark, and dry place, and it should remain just as potent for many months or even years.

As an adaptogen, horny goat weed acts as a mild stressor on the body. This is usually a great thing as it allows your body to adapt to specific forms of stress and become more resilient. However, putting too much stress on the body can be counter-productive and cause multiple side effects, including toxicity. While acute toxicity is extremely rare, taking very high amounts of this herb could lead to chronic toxicity and cause health problems over time. To prevent chronic toxicity or the buildup of tolerance, staying below 5 grams of dry herb or 200 mg of icariin a day is best unless you have a great reason to take more.

While you could safely take higher doses, there is no point in taking more than 5 grams of a dry herb or 200 mg of icariin daily. This amount should give you all of the benefits without meaningful side effects. Paradoxically, taking a higher dose would likely lead to fewer benefits as the body would become accustomed to the herb.

The half-life of horny goat weed in the body is about 2-3 hours. This herb should be processed in your body within 12 hours after consuming it.

The effects of this herb are cumulative. Therefore, you must take it for at least 2-4 weeks to notice the benefits. But again, cycling the herb and not taking it at least twice a week is necessary to prevent tolerance in the long term.

Yes, horny goat weed is vegan-friendly. If you buy this herb in a capsulated form, beware that the capsules often contain animal-based gelatin. Instead, find a brand that puts its products into cellulose capsules.

No, it doesn’t. The herb does not interfere with fasting in any significant way.

References

Most of the information in this guide is based on scientific research that can be found and verified in the PubMed medical library. We highly encourage you to use the library to verify anything you read in this article. We excluded from consideration studies that are either confounded or have a high conflict of interest.

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