Horny Goat Weed 9-in-1 Review: What the Label, the Herb Blend, and the Research Actually Say

Horny goat weed supplements sit in a corner of the market where the marketing runs well ahead of the evidence, so a review of one has to start with a simple rule: marketing copy is a claim, not a fact. Product pages in this category lean on words like "male enhancing," "peak energy," and "proven ability." We will quote some of that language in this review so you can see it, but we will not repeat it as if it were established, and we will check each ingredient against the published research instead.

This article is the foundation review. It covers what the listing says is in the bottle, where the listing contradicts itself, what the research says about horny goat weed and about each of the other herbs in the blend, what the directed dose costs, and what the safety issues are. If you are reading this because you want a performance or hormone shortcut, the honest summary is that the evidence does not support one in this blend, and that some of the individual ingredients have their own, separate guides on this site.

What You Are Buying

The details below come from the Amazon listing (ASIN B0154O5FYC, manufacturer listed as Natures Craft). Label details can change between production runs, so check the bottle you actually receive.

Where the Listing Contradicts Itself

Most supplement problems are not exotic. They are accounting problems: the label and the marketing do not add up. This one has several.

• Nine, seven, or eight? The title says "9 in 1 Formula." The ingredients panel text lists seven items. The feature bullets name seven herbs too, but the set is different: the bullets include Panax ginseng and omit Polypodium vulgare. Counting the union of the two lists gives eight distinct ingredients, still not nine. The "9 in 1" in the title is a marketing label, not an ingredient count you can verify.
• "1000mg" of what? The bullets describe an "extra-strength 1000mg formula." The listing does not say whether 1000 mg is per capsule, per serving of two, or the total of all ingredients, and it gives no milligram amount for any single herb. A total weight tells you almost nothing about a blend, because the number can be reached with a lot of cheap filler-grade powder and a small amount of the ingredient you actually care about.
• Extracts and powders mixed together. Horny goat weed and saw palmetto are listed as extracts, while maca, tribulus, tongkat ali, muira puama, and Polypodium are listed as powders. An extract and a powder of the same plant are not equivalent per milligram, and the listing does not state an extract ratio or a standardization for any of them.
• No icariin figure. Icariin is the compound that the research on horny goat weed is about. The listing text does not state how much icariin, or what percentage, the extract provides. For comparison, a different nine-herb listing at the same price on Amazon does state a horny goat weed amount and a minimum icariin figure in its feature bullets. That does not make that product better, but it shows that stating it is possible.

A proprietary-style blend without per-ingredient amounts is a problem for two reasons. You cannot compare it with any dose used in a study, and you cannot tell whether a high-sounding ingredient list is built on meaningful amounts or on a sprinkle of each herb.

Reading the Marketing Claims

The listing is built around phrases such as "Male Enhancing Supplement," "unleash your peak energy," help to "boost stamina, energy, and male productivity," and herbs "chosen for their proven ability" to support "male efficiency." Those are the listing's words. Under US law, supplements cannot claim to treat or cure disease, so the copy uses soft verbs like "support" and "promote," and the listing carries the standard disclaimer that the statements have not been evaluated by the FDA. In practice the soft language lets a page imply an effect without having to prove it.

It is worth knowing how this class of product has been examined as a whole. Balasubramanian and colleagues (2019) analyzed the six top-ranked erectile dysfunction supplements on Amazon as of September 2018. The most popular ingredients across them were ginseng, horny goat weed, L-arginine, and tongkat ali. The authors searched the literature for all 21 ingredients found and identified 413 studies, of which 59 (16 percent) involved human subjects. Only a minority of those human studies examined single ingredients and reported improvement. They also compared the customer reviews before and after filtering out untrustworthy comments with a review-analysis tool, and found large drops, ranging from 77 to 90 percent, in reviews describing improvements in erection strength, maintenance, satisfaction, and confidence. The takeaway is not that every positive review is fake. It is that the star rating on a supplement page is a poor substitute for evidence. This product's listing shows a rating of 3.9 stars from tens of thousands of reviews, and that number tells you about the buying experience, not about efficacy.

Horny Goat Weed Itself: Epimedium and Icariin

Horny goat weed is the common name for several species of the plant genus Epimedium, used for centuries in traditional Chinese medicine. The compound most often studied is icariin, a flavonoid glycoside, and commercial extracts are usually described by their icariin content. That is the level at which the science exists, so it is the level at which we should judge it. Here is what the evidence consists of.

Test-tube evidence: icariin inhibits PDE5, weakly

Dell'Agli and colleagues (2008) screened plant extracts traditionally used for male impotence against human recombinant phosphodiesterase-5, the enzyme targeted by sildenafil and similar drugs. Of the extracts tested, which included Tribulus terrestris, Ferula hermonis, Cinnamomum cassia, and Epimedium brevicornum, only the Epimedium extract and its active principle icariin were active. The Epimedium extract inhibited the enzyme by 80 percent at 50 micrograms per milliliter, and icariin had an IC50 of 5.9 micromolar. For scale, the same paper reports that a chemically modified derivative of icariin, one that does not occur in the plant, had an IC50 of 75 nanomolar, about the same as sildenafil's 74 nanomolar, and was 80 times more potent than icariin itself. In plain terms, icariin is a real but weak PDE5 inhibitor in a test tube, roughly 80 times weaker than the modified lab compound that matched sildenafil. The authors' interest was in developing the derivative as a drug candidate, not in supplements. A test-tube result tells us a mechanism is plausible. It does not tell us what a capsule does in a person.

Animal evidence: rats with nerve injury

Shindel and colleagues (2010) gave icariin by gavage for four weeks to rats whose cavernous nerves had been injured, at 1, 5, and 10 milligrams per kilogram. The rats treated with the low dose had significantly higher erectile pressure responses to nerve stimulation than control animals, and tissue from treated animals showed more nitric oxide synthase and smooth-muscle marker expression. In separate experiments on cultured pelvic nerve tissue, icariin increased neurite outgrowth. The authors concluded icariin may have neurotrophic effects in addition to PDE5 inhibition. This is interesting science, in a specific injury model, in rats, with purified icariin dissolved in a solvent. It is not a study of a multi-herb capsule in healthy men, and the abstract itself notes that a single dose did not reproduce the effect of four weeks of treatment.

Human evidence: the gap

This is where honesty requires a plain statement. We searched PubMed for human clinical trials of Epimedium or icariin for erectile function and did not find a randomized trial we could verify. The one randomized human trial of Epimedium-derived compounds that our searches did surface was in a completely different population: Zhang and colleagues (2007) gave 100 late-postmenopausal women either a daily Epimedium-derived phytoestrogen flavonoid preparation (60 mg icariin, 15 mg daidzein, and 3 mg genistein) or placebo, with calcium for everyone, for 24 months. The treated group maintained bone mineral density at the lumbar spine and femoral neck while the placebo group lost bone, and neither estradiol nor endometrial thickness changed. That is a bone study in women taking a defined preparation. It says that icariin-containing material has been given to people for two years under trial conditions without a detected endometrial effect, and nothing about sexual function or training in men.

The wider herbal-supplement literature agrees with the gap. Borrelli and colleagues (2018) pooled 24 randomized controlled trials with 2,080 men with erectile dysfunction, covering herbal dietary supplements. The single-herb preparations they found were ginseng, saffron, Tribulus terrestris, pine bark, and maca; horny goat weed was not among the single-herb preparations. Several multi-herb formulations showed preliminary results, and the authors warned that more research was needed and that only seven of the trials had a prevailing low risk of bias. So the claim that horny goat weed works for men is, at present, an extrapolation from a mechanism and a rat study.

The Other Herbs in the Blend

If horny goat weed does not carry the blend, the other ingredients have to. Here is what a literature check turns up for each one named on the listing, with the caveat that none of these studies tested this product or this combination.

Tongkat ali

Tongkat ali (Eurycoma longifolia) has the most encouraging data of the group. A systematic review and meta-analysis by Leisegang and colleagues (2022) included nine studies and pooled five randomized trials, finding a significant increase in total testosterone with supplementation (standardized mean difference 1.352, 95 percent confidence interval 0.565 to 2.138), including in hypogonadal men. The authors called it a possible and promising option but said more research was needed before clinical use. This blend lists tongkat ali as a powder with no stated amount or standardization, so it cannot be matched to whatever preparations those trials used. We cover the evidence and dosing in the tongkat ali guide.

Tribulus terrestris

Tribulus is marketed for testosterone. Vilar Neto and colleagues (2025) systematically reviewed ten clinical studies with 483 participants and found that doses of 400 to 750 mg a day for one to three months improved erectile dysfunction in three of the five studies that measured it, but that eight of ten studies found no significant change in androgen levels, and the two studies that did show an increase involved men with low testosterone and showed a clinically small change of 60 to 70 ng/dL. The authors concluded there was a low level of evidence for erectile function and no robust evidence for raising testosterone. In the Dell'Agli screening above, Tribulus extract did not inhibit PDE5.

Maca

Shin and colleagues (2010) reviewed randomized trials of maca for sexual function and found four that met their criteria, two of which suggested a positive effect on desire in healthy menopausal women or men, one of which found no effect in healthy cyclists, and one in men with erectile dysfunction that showed an effect. They concluded the evidence was limited and that the number of trials, the total sample size, and the average methodological quality were too limited for firm conclusions. The listing names black maca, which is a color variety of the same plant, and the review does not distinguish varieties.

Panax ginseng

The listing bullets name Panax ginseng, though the panel text does not. If it is in your bottle, the best-quality summary is the Cochrane review by Lee and colleagues (2021): nine studies and 587 men with mild to moderate erectile dysfunction, all against placebo, with follow-up of up to 12 weeks. Ginseng had a trivial effect on the erectile function domain of the IIEF-15 (mean difference 3.52, 95 percent CI 1.79 to 5.25, low-certainty evidence, against a minimal clinically important difference of 4), and probably a trivial effect on the IIEF-5 (mean difference 2.39, 95 percent CI 0.89 to 3.88, moderate-certainty evidence, against a minimal important difference of 5). In other words, ginseng's measured effect landed below the threshold the review's authors considered meaningful. The Borrelli review was somewhat more optimistic, pooling five ginseng trials to a standardized mean difference of 0.43 on the IIEF-5, though it also cautioned that study quality varied.

Saw palmetto, muira puama, and Polypodium vulgare

Saw palmetto is a prostate herb, not a sexual or performance herb. Dedhia and McVary (2008), in their review of botanicals for urinary symptoms, noted that saw palmetto had been shown comparable to placebo in a trial of sound methodology, which is the main reason it is a surprising ingredient in a supplement sold on the premise of male vitality. For muira puama (Ptychopetalum olacoides), the top results of our PubMed search were laboratory chemistry and animal studies, and we did not find human trials we could verify. We did not find human clinical research for Polypodium vulgare in the context of this blend either. If a listing contains an ingredient for which no human evidence exists, the honest label for that ingredient is "traditional use," not "proven."

The Dose Problem: No Amounts, No Comparison

For a single-ingredient product, we can lay the label dose next to the study dose and see how they compare. Here we cannot. The listing does not give an amount for horny goat weed, for icariin, for tongkat ali, for tribulus, or for anything else. The directions say two capsules daily, and the total strength claim is "1000mg" without saying what that figure measures.

If the whole "1000mg" is spread across seven or eight ingredients, each herb would average a small fraction of that, in the low hundreds of milligrams or below, and a product with eight ingredients and a total strength claim around 1,000 mg cannot also deliver trial-level doses of each. We are not saying the amounts are low, since the listing does not tell us. We are saying that arithmetic makes it unlikely that every herb is present at a studied dose, and that the listing gives you no way to check.

What It Costs Per Day

At $14.99 for 60 capsules and a directed dose of two capsules a day, the cost works out as follows.

Fifty cents a day is cheap in absolute terms, and that is the honest case for the product: the downside in dollars is small. But cost per day is only meaningful if you know what you are buying a day of. For a product whose active amounts are undisclosed and whose lead ingredient has no human trial for its marketed purpose, a low price per capsule does not tell you the cost per useful dose, because the useful dose is unknown. A different nine-herb listing priced the same on Amazon, in a bottle with twice as many capsules and the same directed two capsules a day, works out to about half as much per day. We mention that comparison only to show how widely the price per day varies for products making similar claims, and not as a recommendation, since we have not evaluated that product. Prices fluctuate, so treat all figures as a snapshot.

Safety, Side Effects, and Interactions

Several safety points apply to this class of product. They are separate from whether it works.

Blood pressure and the heart

The listing itself advises consulting a doctor if you have heart conditions or high blood pressure, and lists possible migraines, upset stomach, abdominal discomfort, and nausea. Ingredients that act on blood vessel tone, and stimulant-adjacent herbs such as ginseng in some people, are a reason to be cautious if your blood pressure or heart rhythm is not normal. We did not find a human safety trial of this blend.

PDE5 inhibitors and nitrates

Because icariin inhibits PDE5 in the test tube, there is a theoretical concern about taking an Epimedium product together with prescription PDE5 inhibitors or with nitrate medicines, since combining those drug classes can cause a dangerous drop in blood pressure. We want to be clear about the status of this point: it is an inference from the mechanism, not a documented interaction from a study we could verify, and icariin is far weaker than the drugs. But the sensible response to a theoretical risk with a serious downside is to tell your prescriber before combining, not to assume the weakness protects you.

Anticoagulants

Izzo and Ernst (2009), in their systematic review of herb-drug interactions, found that ginseng may interact with phenelzine and warfarin, and that no interactions had been reported for saw palmetto. The picture on ginseng and warfarin is mixed: Lee and colleagues (2008) randomized 25 newly diagnosed ischemic stroke patients to warfarin with or without Panax ginseng for two weeks and found no significant difference in prothrombin time or INR between groups, and concluded that ginseng did not influence warfarin's action in that setting, while the earlier case reports and healthy-volunteer trials they cite had conflicting results. The study was small and short, and the listing is unclear on whether ginseng is even in the product. If you take warfarin or another anticoagulant, the right move is to ask the prescriber who manages it.

Undeclared drugs in sexual-enhancement supplements

This is the most important safety point for the category. Tucker and colleagues (2018) analyzed FDA tainted-product warnings from 2007 through 2016 and counted 776 adulterated dietary supplements. Most were marketed for sexual enhancement (353, or 45.5 percent), weight loss (317, or 40.9 percent), or muscle building (92, or 11.9 percent). Among the sexual enhancement products, the most common hidden ingredient was sildenafil, found in 166 of 353 (47.0 percent). The authors warned that the hidden drugs can cause serious harm through accidental misuse, overuse, or interaction with other medicines and conditions. We have no evidence that this product is adulterated, and we are not suggesting it is. We are pointing out that the product category has a documented contamination problem, that the problem is strongest in exactly the market this listing is in, and that a company statement about quality is not a test result. For a man on nitrate medication, an undeclared PDE5 inhibitor is a medical emergency waiting to happen, which is the reason to be cautious about unverified products in this aisle.

Quality and Third-Party Testing

The listing says the product is made in the USA with globally sourced ingredients in a "state-of-the-art facility" under "strict quality standards." The text we retrieved names no third-party certification program, no independent laboratory, and no certificate of analysis. A facility claim is about processes; it is not a lot-level test of what is in the capsule. Given what Tucker and colleagues documented about the category, and given that this listing does not state ingredient amounts, the right level of trust is whatever you can verify. Ask the company for a certificate of analysis for your lot that covers identity of the botanicals and screening for undeclared drug compounds, and be cautious if one is not available. If you compete in tested sport, remember that herbal blends are a common source of positive-test surprises, and a blend without product-level certification is a poor fit.

Who Should Buy It and Who Should Skip It

It could be a reasonable low-cost experiment if you are a healthy adult, you take no medications that interact, you understand that the evidence for this blend as a whole is thin, you do not expect it to raise testosterone or fix a medical problem, and you are comfortable with the unverified quality of an Amazon herbal blend. The dollar risk is small.

Skip it if you take nitrates or PDE5 inhibitors, have heart disease or blood pressure that is poorly controlled, take warfarin or another anticoagulant, are subject to drug testing, or are looking for a dependable effect. If your goal is testosterone, the evidence for an ingredient like tongkat ali is better than for the rest of this blend, and a single-ingredient product with a stated dose at least lets you see what you are taking, and the zinc and sleep fundamentals are covered in our zinc guide and in the turkesterone review, which shows what the same hype cycle looks like in a different ingredient. And if the real concern is a medical one, a clinician is the better first stop than a supplement.

It also helps to know the red flags that this category shares. Our guide to fitness influencer red flags and our research-based blacklist both cover how marketing language is built, and they apply to this listing as much as to anything sold on social media.

How HonestLifter Is Reviewing This Product

HonestLifter's editorial model is longitudinal, as described in our longitudinal review program overview. A one-time first-impressions post tells you very little about a supplement, so the plan for each product we review is a written research review at the start, followed by dated checkpoint updates at 30 days, 60 days, 90 days, 6 months, and 12 months of use. The checkpoint updates are meant to report real notes, not recycled research.

The checkpoint schedule is below, counted from the start of use.

This is a research review built on the manufacturer's listing and published studies; our own notes will be added as dated updates later.

The Bottom Line

This Horny Goat Weed "9 in 1" is a cheap, loosely specified herbal blend. The lead ingredient has a plausible mechanism in a test tube and a favorable result in injured rats, but no randomized human trial that we could find for the purpose the listing implies. The supporting herbs have a patchwork of human data that ranges from trivial (ginseng at the effect sizes pooled in the Cochrane review) to modestly encouraging (tongkat ali) to unproven (muira puama, Polypodium), and none of it was tested in this combination. The listing gives no amount for any ingredient, calls itself nine herbs while listing seven or eight, and offers no independent testing, in a product category where the FDA has documented hidden prescription drugs in nearly half of the sexual-enhancement products it flagged for adulteration.

If you are curious and healthy, the financial risk is small and the realistic expectation should be modest to none. If you take any of the medications named above, or you need something that reliably does what it says, this is not that product. Check with a clinician about anything medical, and watch this page for our dated checkpoint updates.

References

1. Dell'Agli, M., Galli, G.V., Dal Cero, E., Belluti, F., Matera, R., Zironi, E., Pagliuca, G., & Bosisio, E. (2008). Potent inhibition of human phosphodiesterase-5 by icariin derivatives. Journal of Natural Products, 71(9), 1513-1517. doi:10.1021/np800049y. PMID 18778098.
2. Shindel, A.W., Xin, Z.C., Lin, G., Fandel, T.M., Huang, Y.C., Banie, L., Breyer, B.N., Garcia, M.M., Lin, C.S., & Lue, T.F. (2010). Erectogenic and neurotrophic effects of icariin, a purified extract of horny goat weed (Epimedium spp.) in vitro and in vivo. Journal of Sexual Medicine, 7(4 Pt 1), 1518-1528. doi:10.1111/j.1743-6109.2009.01699.x. PMID 20141584.
3. Zhang, G., Qin, L., & Shi, Y. (2007). 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), 1072-1079. doi:10.1359/jbmr.070405. PMID 17419678.
4. Balasubramanian, A., Thirumavalavan, N., Srivatsav, A., Yu, J., Hotaling, J.M., Lipshultz, L.I., & Pastuszak, A.W. (2019). An analysis of popular online erectile dysfunction supplements. Journal of Sexual Medicine, 16(6), 843-852. doi:10.1016/j.jsxm.2019.03.269. PMID 31036522.
5. Borrelli, F., Colalto, C., Delfino, D.V., Iriti, M., & Izzo, A.A. (2018). Herbal dietary supplements for erectile dysfunction: a systematic review and meta-analysis. Drugs, 78(6), 643-673. doi:10.1007/s40265-018-0897-3. PMID 29633089.
6. Leisegang, K., Finelli, R., Sikka, S.C., & Panner Selvam, M.K. (2022). Eurycoma longifolia (Jack) improves serum total testosterone in men: a systematic review and meta-analysis of clinical trials. Medicina (Kaunas), 58(8), 1047. doi:10.3390/medicina58081047. PMID 36013514.
7. Vilar Neto, J.O., de Moraes, W.M.A.M., Pinto, D.V., da Silva, C.A., Caminha, J.S.R., Nunes Filho, J.C.C., et al. (2025). Effects of Tribulus (Tribulus terrestris L.) supplementation on erectile dysfunction and testosterone levels in men: a systematic review of clinical trials. Nutrients, 17(7), 1275. doi:10.3390/nu17071275. PMID 40219032.
8. Shin, B.C., Lee, M.S., Yang, E.J., Lim, H.S., & Ernst, E. (2010). Maca (L. meyenii) for improving sexual function: a systematic review. BMC Complementary and Alternative Medicine, 10, 44. doi:10.1186/1472-6882-10-44. PMID 20691074.
9. Lee, H.W., Lee, M.S., Kim, T.H., Alraek, T., Zaslawski, C., Kim, J.W., & Moon, D.G. (2021). Ginseng for erectile dysfunction. Cochrane Database of Systematic Reviews, 4(4), CD012654. doi:10.1002/14651858.CD012654.pub2. PMID 33871063.
10. Dedhia, R.C., & McVary, K.T. (2008). Phytotherapy for lower urinary tract symptoms secondary to benign prostatic hyperplasia. Journal of Urology, 179(6), 2119-2125. doi:10.1016/j.juro.2008.01.094. PMID 18423748.
11. Izzo, A.A., & Ernst, E. (2009). Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs, 69(13), 1777-1798. doi:10.2165/11317010-000000000-00000. PMID 19719333.
12. Lee, S.H., Ahn, Y.M., Ahn, S.Y., Doo, H.K., & Lee, B.C. (2008). Interaction between warfarin and Panax ginseng in ischemic stroke patients. Journal of Alternative and Complementary Medicine, 14(6), 715-721. doi:10.1089/acm.2007.0799. PMID 18637764.
13. Tucker, J., Fischer, T., Upjohn, L., Mazzera, D., & Kumar, M. (2018). Unapproved pharmaceutical ingredients included in dietary supplements associated with US Food and Drug Administration warnings. JAMA Network Open, 1(6), e183337. doi:10.1001/jamanetworkopen.2018.3337. PMID 30646238.

Product details were taken from the manufacturer's Amazon listing and may change. HonestLifter carries no affiliate links. This article is educational and is not medical advice.