Advancing Gender-Affirming Care Insights Through Unprecedented Scale

In collaboration with Mount Sinai, this study examined how estradiol-based hormone therapy affects estradiol and testosterone levels in nearly 10,000 transgender and gender-nonconforming patients. Higher estradiol generally corresponded with lower testosterone, but results varied. About one-third of patients within the target estradiol range (100–200 pg/mL) had adequately suppressed testosterone (below 50 ng/dL), while another third did not. About half of those above the target estradiol range had suppressed testosterone. Spironolactone did not significantly affect estradiol levels but increased measured testosterone. Findings suggest testosterone suppression may be more useful than strict estradiol targets for some patients, while luteinizing hormone (LH) may help guide dosing after removal of the testes.