Sublingual Estradiol Versus Oral Estradiol in Transgender Women
Phase: EARLY_PHASE1
Conditions: Transgender Persons
Sponsor: Medical College of Wisconsin

Sublingual Estradiol Versus Oral Estradiol in 
Transgender Women 
NCT04036500 
Protocol last modified 3/14/2021 

Sublingual Estradiol Versus Oral Estradiol in Transgender Women 
Protocol Summary 
Primary aim. To establish the pharmacokinetics of sublingual estradiol versus oral 
estradiol. 
Secondary aim. To compare estradiol by LC-MS/MS to estradiol by immunoassay. 
Design: To illuminate the pharmacokinetic parameters of sublingual estradiol in transgender 
women, a pilot crossover study will be conducted. Ten participants, transgender male-to-female 
patients who are naïve to hormone therapy, will be recruited from the Medical College of 
Wisconsin’s Inclusion Health Clinic.  
Methods: Each participant will be dosed with 1 mg oral estradiol. Blood will be drawn via a 
percutaneous intravenous catheter at hours 0,1,2,3,4,6,8. A wash-out period of at least one 
week will allow for complete clearance of the exogenous oral estradiol before testing the 
pharmacokinetics of sublingual estradiol 1 mg on the same ten patients in the same manner. 
Estradiol and estrone by LC-MS/MS will be measured, as well as estradiol by immunoassay. 
These will be sent to ARUP.