He says, The lack of correlation with clomiphene Clomid and breast cancer is not surprising, as clomiphene and tamoxifen used to help prevent the recurrence of breast cancer are closely related medications how quickly can tamoxifen cause uterine cancer Many bodybuilders claim that they obtain excellent outcomes when taking a 10 to 15mg per day dosage and experience only minor adverse effects after using a dose like this for 8 weeks