Genistin is the less active glycoside analog of genistein, an isoflavone found in soy and other plant-based products. Genistin exhibits anticancer, anti-resorptive, anti-osteoporotic, and gastrointestinal motility modulating activities; it also acts as a phytoestrogen. In ovarian cancer cells, genistin induces cell cycle arrest at G2/M and G1 phases as well as apoptosis, inhibiting proliferation. In ovariectomized rats, genistin increases Ca2+ and phosphorus content, improving bone density and strength. Additionally, genistin inhibits ex vivo muscular contractions in the jejunum by decreasing myosin light chain kinase (MLCK) levels and inhibiting myosin activity. Genistin also has estrogenic/anti-estrogenic activities, acting as a selective estrogen receptor modulator (SERM) depending on concentrations and tissue location.