Wild yam is a plant. It contains a chemical called diosgenin. This chemical can be made in the laboratory into various steroids, such as estrogen and dehydroepiandrosterone (DHEA). The root and the bulb of the plant are used as a source of diosgenin, which is prepared as an “extract,”--wild yam extract , a liquid that contains concentrated diosgenin.
Diosgenin or wild yam is often promoted as a “natural alterative” to estrogen therapy, so you will see it used for estrogen replacement therapy, vaginal dryness in older women, PMS (premenstrual syndrome), menstrual cramps, weak bones (osteoporosis), increasing energy and sexual drive in men and women, and breast enlargement. Wild yam does seem to have some estrogen-like activity, but it is not actually converted into estrogen in the body. It takes a laboratory to do that.