Description
Horny goat weed extract from Epimedium leaf, standardised to 10 percent icariin, 60 servings at about 38 cents each. Icariin is a prenylated flavonoid glycoside and it is the compound this plant is calibrated against. The reason to buy a standardised horny goat weed extract rather than the cheap raw leaf powder is that the raw powder almost never states its icariin content, and when it is measured the figure is usually well under one percent.
On the panel
| Plant | Epimedium, leaf, with the species named |
|---|---|
| Standardisation | 10 percent icariin, measured by HPLC on the lot |
| Arithmetic | a 500 mg capsule at 10 percent carries 50 mg of icariin |
| Against raw leaf | unstandardised powder often measures under 1 percent |
| Servings | 60 per bottle, about 38 cents each |
| Marker method | named on the certificate beside the result |
| Price basis | per milligram of icariin, printed under the price |
Why a horny goat weed extract needs its percentage printed
Without it the weight on the front of the bottle is unreadable. A gram of milled leaf and 200 milligrams of a 10 percent extract can carry the same amount of the marker compound, and nothing on either label would tell you so. Percentage times weight is the only comparison that holds.
That is the rule applied across the herbals page, where every botanical states its extract ratio, its plant part and its marker percentage. A horny goat weed extract is one of the clearer examples, because the gap between standardised material and raw powder is more than tenfold.
Species matters as much as percentage
Epimedium is a genus, not a single plant. Several species are harvested commercially and their icariin content differs substantially, which is why the species appears on our panel rather than a common name alone.
Milled leaf from one species looks identical to milled leaf from another, so this is a distinction only a laboratory can make. Identity confirmation on every lot is the control that matters here, and it sits alongside the marker assay on the certificate rather than instead of it.
What the published work on icariin consists of
Most of it is laboratory work. Icariin has been studied in cell and animal models, including work on enzyme systems and on bone cell cultures, at concentrations that have no straightforward human equivalent. Controlled human trials on standardised Epimedium extracts are scarce, and the ones that exist are small.
So there is no established human dose to point you at, and the 10 percent figure is a manufacturing specification rather than a research one. That describes the state of the literature and is not a claim about this bottle, which is a food under United States law.
Raw leaf and horny goat weed extract are different purchases
A bag of milled Epimedium leaf costs a fraction of a standardised bottle and measures a fraction of the marker compound. Both get sold as horny goat weed extract on plenty of shelves, which is a labelling problem rather than a pricing one. The percentage on a standardised horny goat weed extract panel is the only thing that separates the two, and it is the first figure worth checking.
The interaction note
Flavonoid rich extracts are discussed in the pharmacological literature in relation to drug metabolising enzymes, and anyone taking prescription medication should raise this with a pharmacist before starting rather than afterwards. The NCCIH herbs at a glance series is a free government index of what has been formally reviewed for individual plants.
If you are comparing bottles
Multiply the capsule weight by the stated percentage, divide the bottle price by the result, and you have a cost per milligram of icariin. Do that across three products and the ranking usually changes. Our figure is printed under the price, which is the method set out in why price per milligram beats the price on the bottle.
Testing
An independent laboratory confirms species identity, measures the icariin percentage and screens heavy metals, pesticides, aflatoxins and microbials on every lot of horny goat weed extract. Adulteration rather than potency is the real risk in milled botanical material, so identity sits first in that order. Failing lots are withdrawn and the certificate stays published.
Where it sits
This bottle is listed on the men’s page, where the standardised extracts carry their marker percentages and anything without a marker is flagged as such. Your lot certificate is linked on this page and archived with the rest, including the lots that failed.
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