Estrogens are antigonadotropins and are able to suppress the secretion of LH and FSH from the pituitary gland and by extension gonadal testosterone production. High-dose estrogen therapy, including with EE, is able to suppress testosterone levels in men by around 95%, or into the castrate/female range. The dosage of EE required for use as a component of hormone therapy for preoperative transgender women is 50 to 100 µg/day. This high dosage is associated with a high incidence of VTE, particularly in those over the age of 40 years, and it has been said that it should not be used. The dosage of EE used in the treatment of prostate cancer in men is 150 to 1,000 µg/day (0.15–1.0 mg/day). A dosage of EE of 50 μg twice daily (100 μg/day total) has been found to suppress testosterone levels in men to an equivalent extent as 3 mg/day oral diethylstilbestrol, which is the minimum dosage of diethylstilbestrol required to consistently suppress testosterone levels into the castrate range. The ovulation-inhibiting dose of EE by itself and not in combination with a progestin in women is 100 μg/day. However, it has been found to be about 75 to 90% effective at inhibiting ovulation at a dosage of 20 μg/day and about 97 or 98% effective at a dosage of 50 μg/day. In another study, ovulation occurred in 25.2% with an EE dose of 50 μg/day.