Estradiol undecylate (INN, USAN; brand names Delestrec, Depogin, Primogyn Depot, Progynon Depot, others) is a synthetic ester, specifically the 17-undecanoyl ester, of the natural estrogen, estradiol. It has been in use since the mid-1950s, and was formerly often used to treat prostate cancer, but has since largely been superseded by newer agents ...