Yin Yang Huo (Aerial Parts of Epimedium)

Chinese Herb Actions

Chinese Herb Dosage

• What is the typical dosage of Yin Yang Huo?

  9–15 g in decoction (owner’s notes: 3–5 qian). Because the herb is warming and notably drying, it is used with care and is generally not taken long-term at high doses.

  Source: owner’s Five Branches notes; standard materia medica ranges. Reference only — not a prescription.

Chinese Herb Contraindications & Cautions

• Are there cautions or contraindications for Yin Yang Huo?

  Yin Yang Huo is warming and drying and easily injures the yin. It is traditionally not used in yin-deficiency with heat (fire from yin xu) or in rising yang (yang kang), and its drying nature makes prolonged high-dose use inadvisable.

  Source: owner’s Five Branches notes; classical caution (easily injures the yin).

Chinese Herb Toxicity & Overdose

• Low. No significant toxicity is reported for the herb at normal therapeutic doses. Because it is warming and drying, overuse can injure yin and fluids; robust human toxicity data at typical doses are limited.

  Source: materia medica consensus; owner’s Five Branches notes. No toxicity signal in the reviewed research.

Herb-Drug Interactions

• No well-established clinical herb–drug interactions are documented for Yin Yang Huo itself. The material concern is adulteration: over-the-counter “horny goat weed” supplements have repeatedly been found spiked with undeclared sildenafil, tadalafil, or their analogs — for example, a U.S. FDA recall of an epimedium-containing product for undeclared propoxyphenylsildenafil and sildenafil — which can cause dangerous hypotension if combined with nitrate drugs. Preclinical work shows the constituent icariin inhibits PDE5 (below), so caution alongside prescription PDE5 inhibitors or nitrates is reasonable. (Absence of documented interactions is not proof of safety; this is a product-adulteration hazard, not a property of the herb.)

  Source: U.S. FDA recall notice (undeclared propoxyphenylsildenafil/sildenafil in a horny-goat-weed product); PubMed 12646997 (icariin PDE5 inhibition, in vitro).

Western / Biomedical Research

Chinese Herb Clinical Studies & Research

Provided as research context — a summary of published biomedical study, not a therapeutic or medical claim.

• Is there modern research on Epimedium (Yin Yang Huo / icariin)?

  Yes, but the human evidence is limited and most findings are preclinical. The most-studied constituent is the flavonoid icariin. In vitro, icariin is a selective PDE5 inhibitor (IC50 ≈ 0.43 µmol/L, about 168× more selective for PDE5 than PDE4) — the same enzyme sildenafil targets — which is often cited behind the herb’s reputation for erectile function, though a narrative review stresses this remains largely mechanistic and animal-level rather than proven in trials. Icariin and related bioactives also show anti-osteoporotic activity in cell and animal models. Human clinical evidence is limited, and the herb should not be treated as equivalent to prescription PDE5 inhibitors.

  Sources: PubMed 12646997 (icariin on cGMP-specific PDE5 / cAMP-specific PDE4 in vitro, Asian J Androl 2003); PMC 9360520 (icariin & erectile function, narrative review); PMC 11206986 (Epimedium bioactives in osteoporosis, network pharmacology + experimental validation). Research context, not therapeutic claims.

Chinese Herb Notes

• How does Yin Yang Huo compare with Ba Ji Tian and Xian Mao?

  All three fortify Kidney yang, strengthen the sinews and bones, and expel wind-damp — but they differ in strength and dryness. Ba Ji Tian is the mildest and least drying and additionally augments the essence; Yin Yang Huo is extremely drying and easily injures the yin, and is favored for painful obstruction in patients with waning fire at the gate of vitality; Xian Mao is stronger and harsher still and should not be taken long-term.

  Common combinations:

  • In Zan Yu Dan (Special Pill to Aid Fertility) — a warm-and-tonify-yang formula for yang-deficiency infertility and impotence.

  Source: owner’s Five Branches notes (Bensky comparative set); combination confirmed against Sacred Lotus formula membership.