Botanical name: Dioscorea villosa. Wild yam has been included in both bodybuilding and women’s supplements for the same reason: its diosgenin content. Diosgenin is used in the manufacture of synthetic human sex steroids, and Dioscorea is a particularly rich source of it. The necessary steps to convert diosgenin, however, occur only in the laboratory—not in the body. Diosgenin has no known hormonal activity in-vivo.
Wild yam extract itself has weak phytoestrogenic activity in-vitro, however, which lends some (tentative) support to its use for alleviating symptoms of PMS and menopause. Nonetheless, there are no confirming studies, and anecdotal evidence is questionable, at best, due to the presence of other herbals and/or added progesterone in wild yam creams.