Icariin (Epimedium extract)

Tier 3 — weak evidence · Bone health · Testosterone · Cardiovascular

The primary bioactive flavonoid in Epimedium, available as a standardised 40–98% icariin extract. Icariin inhibits PDE5 (similar mechanism to sildenafil, though far weaker), supports testosterone receptor signalling, and promotes osteoblast differentiation. Human RCTs in postmenopausal women demonstrate significant bone density marker improvements. Standardised icariin extracts offer substantially more predictable pharmacology than crude horny goat weed products.

Dose: 200–500 mg standardised extract (40%+ icariin) twice daily