Cnidium monnieri
Cnidium seeds—or “She Chuang Zi”—are used in Chinese traditional medicine to treat skin disorders and boost libido. Several bioactive coumarins have been identified in Cnidium, but osthol is the best known and characterized.
Osthole appears to be orally bioavailable and may improve bone strength, inhibit tumor growth, reduce allergic reactions and have antioxidant/hepatoprotective effects. It also appears to increase nitric oxide levels in penile tissue, and may act as a phosophodiesterase inhibitor similar to Viagra…which may account for Cnidium’s reputation as an aphrodisiac. In addition, one, small study published in an obscure, Chinese language journal reported osthole increased gonadotropin and testosterone levels in rats given high doses.
Cnidium extracts are used in various “male” sexual enhancement products, as well as an increasing number of bodybuilding supplements. Unfortunately, there are no human studies, nor any clue about what constitutes an active, oral dose in humans to achieve any of the above effects.