# Icaritin (Epimedium-derived flavonoid aglycone)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/icaritin-epimedium-derived-flavonoid-aglycone
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-04-05
**Evidence Score:** 1 / 10
**Category:** Compound
**Also Known As:** Anhydroicaritin, 3,5,7-trihydroxy-2-(4-methoxyphenyl)-8-(3-methylbut-2-en-1-yl)chromen-4-one, SNG1705 (pharmaceutical formulation), Epimedium flavonoid aglycone, ICT

## Overview

Icaritin is a prenylflavonoid aglycone metabolite of icariin that exerts its principal effects through activation of estrogen receptor beta (ERβ), modulation of the Wnt/β-catenin and PI3K/Akt signaling pathways, and suppression of NF-κB-driven [inflammatory](/ingredients/condition/inflammation) and proliferative cascades. In preclinical osteogenic studies, icaritin at 1–10 μM dose-dependently increased osteocalcin mRNA expression up to 3.3-fold and bone sialoprotein expression up to 3.4-fold in human bone marrow mesenchymal stem cells, while a semisynthetic icaritin soft capsule (SNG1705) received conditional approval in China in 2022 as the first botanical drug for advanced hepatocellular carcinoma, demonstrating improved overall survival in a phase II/III trial.

## Health Benefits

- **Bone Formation and Osteoprotection**: Icaritin stimulates osteogenic differentiation of bone marrow mesenchymal stem cells by inactivating GSK3β and suppressing PPARγ, increasing osteocalcin and bone sialoprotein mRNA expression up to 3.3-fold and 3.4-fold respectively at 10 μM, while simultaneously inhibiting adipogenic differentiation.
- **Anticancer Activity**: Icaritin inhibits tumor cell proliferation and downregulates NF-κB signaling in multiple cancer cell lines including SKOV3 ovarian cancer cells at 25–100 μM concentrations over 48 hours, and has demonstrated sufficient clinical efficacy in hepatocellular carcinoma to receive conditional regulatory approval in China.
- **Neuroprotection**: Icaritin and its parent compound icariin activate the PI3K/Akt survival pathway to counteract amyloid-beta (Aβ₂₅₋₃₅)-induced apoptosis in neuronal PC12 cells, suggesting a potential role in attenuating neurodegeneration relevant to Alzheimer's disease pathology.
- **[Immunomodulat](/ingredients/condition/immune-support)ion**: Icaritin modulates innate and adaptive immune responses by influencing cytokine secretion and T-cell activation, with preclinical evidence suggesting it can shift the tumor microenvironment toward an immunostimulatory phenotype through effects on dendritic cell maturation and macrophage polarization.
- **Anti-adipogenic Effects**: By downregulating PPARγ, lipoprotein lipase (LPL), and aP2 mRNA expression in mesenchymal stem cells, icaritin inhibits fat cell differentiation, offering a mechanistic rationale for potential applications in metabolic syndrome and obesity-related bone quality decline.
- **[Cardiovascular](/ingredients/condition/heart-health) and Endothelial Support**: Icaritin exhibits estrogenic activity via selective ERβ agonism, which in preclinical models is associated with improved endothelial nitric oxide synthase (eNOS) activity and vasodilation, consistent with the traditional use of Epimedium for cardiovascular and sexual health.
- **Anti-inflammatory Signaling**: Icaritin suppresses the NF-κB transcription factor pathway, reducing downstream production of [pro-inflammatory cytokine](/ingredients/condition/inflammation)s such as IL-6, TNF-α, and IL-1β, which is mechanistically relevant across its osteoprotective, anticancer, and [neuroprotective](/ingredients/condition/cognitive) activity profiles.

## Mechanism of Action

Icaritin functions as a selective estrogen receptor modulator (SERM), binding preferentially to estrogen receptor beta (ERβ) and activating downstream gene transcription programs that promote cell survival, differentiation, and anti-inflammatory responses without the full agonist activity at ERα associated with classical estrogen. In osteogenic contexts, icaritin inactivates glycogen synthase kinase-3 beta (GSK3β), stabilizing β-catenin and enabling Wnt/β-catenin pathway activation, which drives transcription of osteoblast-specific genes including Runx2, osteocalcin (OCN), and bone sialoprotein (BSP), while concurrently suppressing PPARγ-mediated adipogenesis. In cancer and neuronal cell models, icaritin activates the phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) survival axis, increasing phosphorylation of Akt at Ser473, which suppresses pro-apoptotic factors including Bad and caspase-9 and promotes cell survival or selectively induces apoptosis in malignant cells through context-dependent modulation of the Bcl-2/Bax ratio. Additionally, icaritin inhibits the IκB kinase (IKK) complex, preventing nuclear translocation of NF-κB p65 and thereby reducing transcription of genes encoding [pro-inflammatory cytokine](/ingredients/condition/inflammation)s and survival factors in tumor microenvironments.

## Clinical Summary

The most clinically significant trial for icaritin is the randomized phase II/III study of SNG1705 (oral icaritin soft capsules, 600 mg twice daily) in advanced HCC patients, which enrolled approximately 120–200 patients across multiple Chinese centers and demonstrated improved median overall survival compared to placebo in a biomarker-enriched subgroup, constituting the primary basis for NMPA conditional approval in 2022. Secondary endpoints including disease control rate and immune biomarker modulation (reduction in immunosuppressive FOXP3+ Treg infiltration) were also reported as favorable, suggesting an immunostimulatory rather than purely cytotoxic mechanism of antitumor efficacy. For osteoporosis, available clinical data derive from studies using whole Epimedium extracts standardized to total flavonoids rather than isolated icaritin, limiting direct clinical attribution; these studies report modest improvements in [bone mineral density](/ingredients/condition/bone-health) over 12–24 months in postmenopausal women but lack the statistical power and placebo control quality needed for strong conclusions. Confidence in icaritin's clinical utility is moderate-to-emerging for HCC specifically and remains low-to-preliminary for all other therapeutic applications pending dedicated human trials.

## Nutritional Profile

Icaritin is a pure bioactive small molecule (molecular formula C₂₁H₂₀O₅, molecular weight 356.38 g/mol) rather than a whole food, and therefore does not possess a conventional nutritional profile of macronutrients or vitamins. As a prenylflavonoid aglycone, it belongs to the flavonol subclass of polyphenols, characterized by a prenyl substituent at the C-8 position of the A-ring and hydroxyl groups at C-3, C-4', and C-7 positions that confer both estrogenic activity and [antioxidant](/ingredients/condition/antioxidant) capacity. Icaritin's lipophilicity (predicted logP approximately 3.2–3.8) and low molecular weight relative to its parent glycoside icariin (676.67 g/mol) theoretically improve cellular membrane permeability, though its oral bioavailability as a pure compound is limited by poor aqueous solubility (less than 0.1 mg/mL in physiological buffers) and rapid phase II hepatic conjugation (glucuronidation and sulfation). The parent herb Epimedium also contains flavonoid glycosides (epimedin A, B, C; icariin; baohuoside I), phytosterols, polysaccharides, and lignans that may contribute to observed in vivo effects when whole extracts rather than isolated icaritin are consumed.

## Dosage & Preparation

- **Oral Soft Capsules (Pharmaceutical-grade, SNG1705/Jinyouli)**: 600 mg icaritin twice daily (1200 mg/day total), taken orally; this is the dose used in the approved HCC clinical program in China and represents the only rigorously validated clinical dosing regimen.
- **Standardized Epimedium Extract Capsules/Tablets**: Typically standardized to 10–40% total icariin flavonoids by HPLC; doses of 500–1000 mg extract (yielding variable icaritin depending on formulation and intestinal conversion) used in [bone health](/ingredients/condition/bone-health) studies, though icaritin content per dose is rarely specified on commercial products.
- **Traditional Decoction (Herba Epimedii)**: 6–15 g dried herb per day brewed as aqueous decoction per Chinese Pharmacopoeia guidance; this method produces low concentrations of free icaritin as most bioactive compounds remain as glycosides (icariin) until intestinal hydrolysis.
- **Semisynthetic Isolated Icaritin Powder (Research Grade)**: Used at 0.1–10 μM in cell culture studies; direct oral supplementation as pure powder is not yet standardized for consumer use outside clinical trial contexts.
- **Timing Notes**: Peak plasma icaritin levels following Epimedium decoction are observed approximately 8 hours post-ingestion, reflecting slow intestinal conversion of icariin to icaritin; administration with food may alter this conversion kinetics.
- **Standardization Guidance**: For osteoprotective applications, choose products specifying icaritin or icariin content by percentage rather than generic 'Epimedium extract' to ensure consistent bioactive delivery.

## Safety & Drug Interactions

Icaritin as an isolated compound has a limited formal human safety dataset; the clinical trials conducted in China for the HCC indication reported the compound as generally tolerable at 1200 mg/day, with the most commonly noted adverse events being mild gastrointestinal discomfort, elevated liver enzymes (hepatotoxicity signal warranting monitoring), and fatigue, though comprehensive adverse event tables from the full trial have not been widely published in English-language peer-reviewed literature. Due to its selective ERβ agonist and partial ERα activity, icaritin is contraindicated or requires medical supervision in individuals with hormone-sensitive cancers (breast, uterine, ovarian), and should be avoided during pregnancy and lactation given insufficient safety data and theoretical teratogenic risk from estrogenic activity. Drug interaction risks include potential additive or antagonistic effects with anticoagulants (icaritin may inhibit platelet aggregation), hormone replacement therapies and selective estrogen receptor modulators (tamoxifen, raloxifene), immunosuppressants, and CYP3A4 substrates or inhibitors, as Epimedium flavonoids are known CYP3A4 modulators in preclinical models. Individuals with known liver disease should exercise particular caution given the hepatic [metabolism](/ingredients/condition/weight-management) burden and the hepatotoxicity signals observed, and all use of isolated icaritin supplementation outside pharmaceutical settings should occur under the guidance of a qualified healthcare provider.

## Scientific Research

The evidence base for icaritin consists predominantly of in vitro cell culture and in vivo rodent model studies, representing a preclinical body of work rather than a mature clinical evidence portfolio; the largest body of mechanistic data involves osteogenic differentiation of mesenchymal stem cells and cancer cell line proliferation assays. Notably, icaritin has advanced further into clinical translation than most phytochemical aglycones: a semisynthetic icaritin formulation (SNG1705/AL3818, branded as Jinyouli) completed a randomized, controlled phase II/III trial in patients with advanced hepatocellular carcinoma (HCC) in China, demonstrating statistically significant improvement in overall survival, particularly in patients with specific immune biomarker profiles (FOXP3+/CD4+ T-cell ratio), leading to conditional approval by China's National Medical Products Administration (NMPA) in 2022. Additional early-phase clinical investigations have examined icaritin-containing Epimedium extracts for [osteoporosis](/ingredients/condition/bone-health) endpoints, though these trials are smaller and use mixed botanical preparations that preclude attribution of effects to icaritin alone. Overall, the clinical evidence is promising but narrow in therapeutic scope, with robust data only for HCC, and the osteogenic, [neuroprotective](/ingredients/condition/cognitive), and [immunomodulatory](/ingredients/condition/immune-support) claims remain at preclinical stages requiring human trial validation.

## Historical & Cultural Context

Epimedium, known in Chinese medicine as Yin Yang Huo (淫羊藿), has been documented in Chinese pharmacopeias for over 2,000 years, with its earliest recorded reference appearing in the Shennong Bencao Jing (Divine Farmer's Classic of Materia Medica, approximately 200 CE), where it was described as tonifying kidney yang, strengthening sinews and bones, and enhancing male reproductive vitality. The herb's common English name 'horny goat weed' originates from a Tang Dynasty (618–907 CE) legend attributed to the herbalist Tao Hongjing, who reportedly observed that goats grazing on the plant exhibited increased sexual activity, a narrative that has persisted in ethnobotanical literature. Traditional preparations included decoctions, wines, and pill formulations combined with other kidney-tonifying herbs such as Morinda officinalis and Cuscuta chinensis in classical formulas like Zuogui Wan and Yougui Wan for [osteoporosis](/ingredients/condition/bone-health), sexual dysfunction, and age-related decline. Modern pharmacognostic research beginning in the 1960s and expanding significantly in the 1990s–2000s isolated icariin and subsequently icaritin as the principal bioactive flavonoids responsible for the plant's observed biological activities, bridging traditional indication with molecular pharmacology.

## Synergistic Combinations

Icaritin demonstrates mechanistic synergy with vitamin D3 (cholecalciferol) and vitamin K2 (menaquinone-7) in osteogenic applications, as icaritin activates Wnt/β-catenin and ERβ pathways while vitamin D3 upregulates osteocalcin carboxylation machinery and K2 activates osteocalcin-mediated calcium routing, creating complementary and non-overlapping osteoblast activation mechanisms. In oncology preclinical models, icaritin has been investigated in combination with sorafenib for HCC, with evidence suggesting that icaritin's [immunomodulatory](/ingredients/condition/immune-support) activity (reducing Treg infiltration) may sensitize tumors to the anti-angiogenic effects of sorafenib, a rationale that informed the design of the SNG1705 clinical program. For [neuroprotective](/ingredients/condition/cognitive) applications, pairing icaritin-containing Epimedium extracts with phosphatidylserine or omega-3 DHA may produce additive PI3K/Akt pathway support alongside membrane fluidity optimization, representing a theoretically coherent nootropic and neuroprotective stack, though direct human combination data are not yet available.

## Frequently Asked Questions

### What is icaritin and how is it different from icariin?

Icaritin is the aglycone (sugar-free) metabolite of icariin, the primary flavonoid glycoside in Epimedium (horny goat weed). While icariin has a molecular weight of 676.67 g/mol and requires intestinal enzymatic hydrolysis to become active, icaritin (356.38 g/mol) is the smaller, more lipophilic bioactive form produced by gut microbiota or semisynthetic processing, and it exhibits greater cellular permeability and direct receptor binding activity compared to its parent glycoside.

### Has icaritin been approved for cancer treatment?

Yes, a semisynthetic icaritin formulation branded as Jinyouli (SNG1705) received conditional approval from China's National Medical Products Administration (NMPA) in 2022 for the treatment of advanced hepatocellular carcinoma (liver cancer), making it the first botanical drug approved for this indication in China. The approval was based on a randomized clinical trial demonstrating improved overall survival, particularly in patients with favorable immune biomarker profiles (low FOXP3+/CD4+ T-cell ratios), and is classified as conditional pending confirmatory trial data.

### What dose of icaritin is used for bone health?

No standardized clinical dose of isolated icaritin has been established for osteoporosis in validated human trials; most bone health research has used whole Epimedium extracts standardized to 10–40% total icariin flavonoids at 500–1000 mg per day. The only rigorously validated human dosing protocol involves the pharmaceutical icaritin preparation SNG1705 at 600 mg twice daily (1200 mg/day) for hepatocellular carcinoma. Consumers seeking bone support should look for Epimedium products with specified icariin or icaritin content and consult a healthcare provider for guidance.

### Is icaritin safe for women with hormone-sensitive conditions?

Icaritin acts as a selective estrogen receptor modulator (SERM) with preferential activity at ERβ, which raises theoretical concerns for individuals with hormone-sensitive cancers such as breast, uterine, or ovarian cancer, and it should be avoided in these populations without explicit oncologist guidance. It is also contraindicated during pregnancy and breastfeeding due to insufficient safety data and potential estrogenic effects on fetal or infant development. Women currently taking tamoxifen, aromatase inhibitors, or hormone replacement therapy should consult their physician before using any Epimedium or icaritin-containing supplement.

### How does icaritin support bone formation at the molecular level?

Icaritin promotes osteogenesis by inactivating glycogen synthase kinase-3 beta (GSK3β), which stabilizes β-catenin and activates the Wnt signaling pathway, driving transcription of osteoblast differentiation genes including Runx2, osteocalcin (OCN), and bone sialoprotein (BSP). In human mesenchymal stem cell studies, icaritin at 10 μM increased osteocalcin mRNA expression 3.3-fold and BSP expression 3.4-fold, while simultaneously suppressing PPARγ-mediated adipogenic differentiation, effectively shifting stem cell fate toward bone-forming osteoblasts rather than fat cells.

### Does icaritin need to be converted from icariin in the body to be effective?

Icaritin is the aglycone form of icariin, meaning it has already had its sugar molecules removed, allowing for direct absorption and utilization without requiring gut bacteria conversion. While icariin can be metabolized to icaritin in the digestive system, supplementing with icaritin directly may provide more consistent bioavailability and faster bioactivity. This makes icaritin potentially more efficient for bone health and other therapeutic applications compared to relying on bacterial metabolism of icariin.

### What is the mechanism behind icaritin's effect on bone marrow stem cells?

Icaritin promotes bone formation by suppressing GSK3β kinase and inhibiting PPARγ signaling in bone marrow mesenchymal stem cells, which shifts these cells toward bone-forming osteocytes rather than fat-storing adipocytes. This dual action increases expression of critical bone proteins—osteocalcin and bone sialoprotein—by up to 3.3- and 3.4-fold at physiological concentrations (10 μM). By simultaneously enhancing osteogenic differentiation while blocking adipogenic pathways, icaritin addresses both bone quality and metabolic health at the cellular level.

### Are there specific populations that should prioritize icaritin supplementation over other bone-support compounds?

Icaritin may be particularly beneficial for individuals at risk of osteoporosis or with poor osteogenic capacity, as its direct stimulation of bone marrow stem cell differentiation addresses a fundamental mechanism of bone loss. Those with age-related bone density decline or individuals seeking alternatives to hormone-based therapies may find icaritin's mechanism of action especially relevant. However, individuals with active hormone-sensitive cancers or pregnant/nursing women should avoid icaritin due to its estrogenic properties and limited safety data in these populations.

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