Horny goat weed extract (Icariin)

Horny goat weed extract is prepared from the dried leaf and aerial parts of Epimedium, the drug known in the Chinese materia medica as yin yang huo or Epimedii Folium. The Chinese Pharmacopoeia recognises Epimedium brevicornu Maxim., E. sagittatum (Sieb. & Zucc.) Maxim., E. pubescens Maxim. and E. koreanum Nakai, with E. wushanense T. S. Ying carried as a separate article. It is worth being precise about the plant part, because the name misleads buyers: this is a leaf and aerial-part extract, not a root or rhizome extract, and a specification that says "root" has been copied from the wrong template. The marker compound is icariin, CAS 489-32-7, C33H40O15, molecular weight 676.66, melting point 223-225 °C — a prenylated flavonol carrying a rhamnose at C-3 and a glucose at C-7. It sits alongside epimedin A, B and C and baohuoside I (icariside II), and a full HPLC fingerprint rather than a single number is the only reliable way to match one lot to the next. The extraction ratio is not a fixed number and no honest supplier will quote one as if it were. The Chinese Pharmacopoeia requires icariin at not less than 0.50% in Epimedii Folium, while published surveys of natural leaf report a range of roughly 0.08% to 0.64% depending on species, altitude and harvest — so the mass of leaf behind a kilogram of 20% icariin extract varies substantially with the incoming raw material. Thovek states the native drug-to-extract ratio and the species composition on every specification instead of quoting a marketing ratio. Icariin itself is practically insoluble in water, less than 1 mg/mL in ethanol at 25 °C and around 50 mg/mL in DMSO, and it is light-sensitive; extracts are therefore packed opaque and formulators working in aqueous systems should plan for a solubilised or dispersible format rather than assuming the powder will go into solution. Two commercial points deserve emphasis. First, this is a product category with a documented adulteration history: synthetic PDE-5 inhibitor drugs — sildenafil, tadalafil and their structural analogues — have repeatedly been found undeclared in finished sexual-enhancement products, and recalls in this space are routine. Thovek screens every lot by LC-MS/MS for those compounds and reports the result on the certificate of analysis; a buyer's own release specification should require the same regardless of supplier. Second, on origin: Epimedium is not cultivated commercially in India. The only representative of the genus on the subcontinent, E. elatum, is a rare endemic of the north-western Himalaya under conservation pressure and is not a commercial source, so the leaf is of Chinese origin and is declared as such. The material is plant-derived and vegan, with no bovine, porcine, marine, dairy, egg, fish, crustacean, nut, sesame or gluten input. Every lot ships with HPLC assay and identity, loss on drying, ash, heavy metals by ICP-MS, residual solvents against ICH Q3C, pesticide screening, adulterant screening and microbiology.