Source Naturals' Eternal Woman line is designed for menopausal women to experience the Freedom to Change naturally. Genistein, an isoflavone phytonutrient derived from soybeans, has been the focus of scientific research since 1966. Studies have shown that genistein can bind to the same receptor sites as estrogen. Source Naturals Genistein Soy Complex is made from isoflavone-rich soybean powder that yields a consistent standardized isoflavone content. This unique chemical-free process requires approximately 400 pounds soybeans to yield just one pound of finished powder.