Icariin
Compiled from published pharmacological and botanical literature. Not independently verified by Herbuno. Spotted an error or have a correction? Flag it below →
| Chemical Class | Prenylated flavonol glycoside |
| Molecular Formula / CAS | C₃₃H₄₀O₁₅ · CAS 489-32-7 |
| Primary Botanical Source(s) | Horny goat weed (Epimedium spp., especially E. sagittatum) |
| Plant Part | Aerial parts (leaf) |
| Typical Content | The major and most abundant bioactive flavonoid of Epimedium herb, among more than 260 identified constituents |
| Solubility / Format | Available as standardised extract powders at multiple potency grades |
| Sourcing Status | Product-live — genuine match via Herbuno’s horny goat weed extract line |
| Buy from Herbuno | Icariin 40% Powder (Horny Goat Weed Extract) · Icariin 20% Powder |
Name origin: Icariin takes its name from the genus Epimedium, whose common English name, horny goat weed, derives from a Chinese folk account of goats becoming notably energetic after grazing on the plant. Traditional use: Herba Epimedii (known as yin yang huo in Chinese) has been used in Traditional Chinese Medicine for centuries specifically for sexual dysfunction, fatigue, joint pain and bone-related conditions in aging, making icariin’s modern research focus areas — erectile function, bone metabolism and cardiovascular health — a close continuation of its traditional indications rather than an unrelated modern discovery. Research trajectory: Icariin was identified as Epimedium’s major bioactive constituent and became the standardisation marker for commercial horny goat weed extract; research has expanded from early phosphodiesterase-inhibition studies relevant to erectile function into a broad and still-active research programme covering bone metabolism, cardiovascular protection, neuroprotection and anti-inflammatory activity. Commercial source: Horny goat weed is the standard commercial source of icariin, and Herbuno’s standardised extracts reflect this well-established, genuine botanical match.
Evidence for Icariin Applications
Icariin inhibits phosphodiesterase type 5 (PDE5), the same enzyme target as pharmaceutical erectile dysfunction medications, though considerably less potently — laboratory testing has found sildenafil roughly 80 times more potent than icariin at this target. In a rat model of cavernous nerve injury, four weeks of daily icariin treatment improved penile hemodynamic parameters following nerve injury, with treated animals showing increased penile neuronal nitric oxide synthase and smooth muscle content compared to untreated injured controls (Shindel et al. 2010). This remains an animal-model finding, and no high-quality randomised human clinical trial data for icariin specifically in erectile dysfunction was identified in this review. Claim strength: Emerging.
A substantial and separate research literature has developed around icariin’s cardiovascular protective effects, particularly in atherosclerosis: a dedicated review describes icariin as exerting antioxidant, anti-inflammatory and lipid-modulating activity across endothelial cells, vascular smooth muscle cells and macrophages, positioning it as a candidate anti-atherosclerotic agent within the broader Chinese medicinal herb literature (et al. 2017). This cardiovascular research base is largely preclinical (cell and animal model) at present. Claim strength: Emerging.
Icariin has also been extensively studied for bone-related applications, showing osteogenic effects including enhanced proliferation and differentiation of bone marrow stromal cells and stimulated production of bone morphogenetic protein 2, research that connects directly to Epimedium’s traditional use for age-related bone and joint complaints. This osteogenic research programme is among the more mechanistically detailed areas of icariin pharmacology, though it likewise remains predominantly preclinical rather than confirmed in dedicated human bone-density trials. Claim strength: Emerging.
A documented safety consideration for Epimedium-based supplements deserves direct mention: a case report describes severe muscle spasms and elevated creatine kinase and creatinine associated with Epimedium use, part of a small but real body of published toxicity case reports involving Herba Epimedii preparations, including prior reports of tachycardia and hypomania (et al.). A review of aphrodisiac ingredients notes the lack of randomised controlled trial-level human data for Epimedium specifically, alongside these documented adverse event reports. Claim strength: Moderate (safety).
Formulators should note that icariin research spans a genuinely unusual breadth of applications — erectile function, bone metabolism, cardiovascular protection and neuroprotection — reflecting both Epimedium’s broad traditional use and icariin’s status as a well-studied flavonoid, but that human randomised controlled trial data remains limited relative to the preclinical literature across essentially all of these application areas. Claim strength: Moderate.
Dosage & Formulator Specification
No formally established human clinical dosing range exists for isolated icariin; animal research on erectile function used daily oral doses of 1–10 mg/kg body weight over four weeks, which does not directly translate to a validated human supplement dose given the absence of confirmatory human trials at this time.
Analytical quantification of icariin is performed by HPLC, the standard method for horny goat weed extract quality control; because Epimedium contains numerous related flavonoid glycosides beyond icariin itself, formulators should request icariin-specific chromatographic data rather than a total flavonoid figure, which would not isolate icariin content specifically.
Given the documented case reports of adverse effects (muscle spasms, elevated creatine kinase, tachycardia, hypomania) associated with Epimedium products, formulators should include appropriate safety documentation and dosing guidance rather than treating horny goat weed extract as a routine, low-risk botanical, and should be aware that reported effects on hormone levels warrant caution for individuals with hormone-sensitive conditions.
Regulatory positioning for icariin follows established horny goat weed botanical-ingredient precedent in most markets, given Epimedium’s long traditional medicinal use history; no icariin-specific regulatory limit exists. Formulators should avoid overstating erectile-function or other claims given the current absence of high-quality human randomised controlled trial data specific to icariin.
Frequently Asked Questions — Icariin
It works through a related mechanism, inhibiting the same PDE5 enzyme target as sildenafil (Viagra), but laboratory testing has found icariin roughly 80 times less potent at this target. Its supporting evidence also comes mainly from animal studies rather than the extensive human clinical trial data behind pharmaceutical PDE5 inhibitors.
Documented case reports describe adverse effects associated with Epimedium use, including severe muscle spasms with elevated creatine kinase, as well as separate reports of tachycardia and hypomania. A review of aphrodisiac herbs also notes the lack of randomised controlled trial-level human safety data for Epimedium specifically.
A substantial body of research covers icariin’s bone-supportive (osteogenic) effects and cardiovascular protective, anti-atherosclerotic activity, both of which connect to Epimedium’s traditional use for age-related bone, joint and vitality complaints. Most of this research remains preclinical.
Not yet, across most of its studied applications. A review of aphrodisiac ingredients specifically notes the absence of high-quality randomised controlled trial data for Epimedium/icariin, and this gap between preclinical and human evidence applies broadly across icariin’s other research areas as well.
Related compounds: Forskolin, L-DOPA