Genistein is one of several known isoflavones. Isoflavones, such as genistein and daidzein, are found in a number of plants including lupin, fava beans, soybeans, kudzu, and psoralea being the primary food source,also in the medicinal plant, Flemingia vestita and coffee.
Genistein is an isoflavonoid phytoestrogenic compound found in soybeans, pea pods, and other legumes. The estimated human normal dietary intake of genistein, primarily as glycosides, is 0 to 0.5 mg/kg. Genistein is present in much greater amounts in nutritional supplements. Genistein is carcinogenic in female neonatal mice, inducing endocrine-dependent uterine tumors in a fashion similar to diethylstilbestrol (DES).