Herb of the month: Epimedium sagittatum
Epimedium sagittatum (Horny Goat Weed) is a perennial creeping rhizome from the Berberidaceae family of plants. Horny goat weed refers to numerous herb species of the Epimedium genus and may be known as "yin yang huo”. About 52 species of Epimedium grow in Europe, Asia, the Middle East and Far East.
Historical uses:
For around 2000 years in Traditional Chinese Medicine (TCM), Horny goat weed has been used to treat impotence, and infertility, as a tonic, aphrodisiac and antirheumatic. In TCM it is thought to be “nourishing the kidney and reinforcing the Yang”
Fun fact:
A legend states that the name Horny Goat Weed originated from a goat herder noticing his flock of goats became sexually stimulated after eating this plant. Other names that it is known by include Barrenwort, Bishop’s Hat, Rowdy Lamb Herb, and Fairy Wings.
Parts used:
Aerial parts (leaves and stem)
Major chemical constituents:
Rich in flavonoids (including Icariin), lignans, phenol glycosides, ionines, sesquiterpenes and phenylethanoid glycosides.
Therapeutic actions:
The flavonoids, such as icariin, icaritin or epimedin are thought to be antiviral, anti-inflammatory, immunomodulatory and hepatoprotective.
Key benefits:
- Sexual dysfunction- Horny goat weed has been traditionally used for erectile dysfunction
- Libido maintenance as an aphrodisiac.
Clinical uses:
Sexual dysfunction: traditionally extracts of Epimedium have been used to treat “coldness”, reinforce kidney yang and male impotence. Epimedium sagittatum has been used since the Han dynasty (202 BC-AD 220) to treat erectile dysfunction (ED) (Ma et al.2011). Modern studies have shown there is a protein called phosphodiesterase-5 (PDE-5) that interferes with the mechanisms that create an erection and Epimedium is able to inhibit this protein. (Ma et al. 2011) Icariin which is a component of Horny goat weed, inhibits the action of PDE-5 that is blocking the dilation of arteries to the penis. When PDE-5 is inhibited, it allows blood to fill the arteries and cylinders in the penis and create an erection (Healthline, 2023). However, studies in humans are lacking and most of the ED research has been on rodents.
Osteoporosis: A meta-analysis of several small studies show that horny goat weed can modestly improve bone mineral density (BMD) in osteoporosis (Shi et al. 2022) When horny goat weed was added to conventional therapies it was shown to have a larger effect on BMD. The studies suggested horny goat weed for greater than 3 months at around 600mg day as an complement to conventional therapy had the best results on BMD. (Shi et al. 2022)
Cardiovascular disease: some in vitro and in vivo studies suggest that horny goat weed is useful for treating atherosclerosis, heart disease and cardiovascular disease. However, these studies are on the isolated constituent Icariin not just the herb itself (Fang et al, 2017).
Postmenopausal conditions: Initial research suggests postmenopausal women taking horny goat weed for < 6months slightly decreased total cholesterol and triglyceride levels when compared with placebo (Natural Medicines Database, 2023).
Cautions/Contraindications:
- Avoid use in pregnancy, may harm developing foetus.
- Bleeding disorders- Theoretically Horny goat weed may slow clotting so could increase the risk of bleeding.
- Hormone sensitive cancers- Horny goat weed can increase oestrogen levels in some people and may worsen oestrogen sensitive conditions.
- Surgery- due to blood clotting changes, stop 2 weeks before surgery.
References
Fang, J., & Zhang, Y. (2017). Icariin, an Anti-atherosclerotic Drug from Chinese Medicinal Herb Horny Goat Weed. Frontiers in pharmacology, 8, 734. https://doi.org/10.3389/fphar.2017.00734
Healthline: Horny Goat Weed: Does It Work to Treat Erectile Dysfunction? [Internet] [Updated 2023 Feb 01]. https://www.healthline.com/health/erectile-dysfun...
Horny Goat Weed. (2022). In LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. National Institute of Diabetes and Digestive and Kidney Diseases. https://pubmed.ncbi.nlm.nih.gov/35998248/
Ma, H., He, X., Yang, Y., Li, M., Hao, D., & Jia, Z. (2011). The genus Epimedium: an ethnopharmacological and phytochemical review. Journal of ethnopharmacology, 134(3), 519-541. https://pubmed.ncbi.nlm.nih.gov/21215308/
Medline Plus: Natural Medicines Comprehensive Database Consumer Version [Internet]. Stockton (CA): Therapeutic Research Faculty; c1995-2018. Horny Goat Weed; [updated 2020 Jun 4; reviewed 2021 Aug 21; cited 2023 Feb 24]. https://medlineplus.gov/druginfo/natural/699.html#OtherNames
Natural Medicines Database. (2023) [Monograph]https://naturalmedicines-therapeuticresearch-com/databases/food,-herbs-supplements/professional.aspx?productid=699#effectiveness
Pullaiah, T. (2021). Encyclopaedia of World Medicinal Plants 2nd Revised and Enlarged Edn in 7 Vols. Astral International Pvt Ltd.
Shi, S., Wang, F., Huang, Y., Chen, B., Pei, C., Huang, D., Wang, X., Wang, Y., Kou, S., Li, W., Ma, T., Wu, Y., & Wang, Z. (2022). Epimedium for Osteoporosis Based on Western and Eastern Medicine: An Updated Systematic Review and Meta-Analysis. Frontiers in pharmacology, 13, 782096. https://doi.org/10.3389/fphar.2022.782096
