Guideline Recommendations for Hormone Therapy Monitoring and Adjustment in Transgender Women

Monitoring Frequency

The Endocrine Society recommends evaluating patients every 2–3 months during the first year of hormone therapy and then 1–2 times annually thereafter. 2

The Endocrine Society sets the target testosterone level for transgender women at < 55 ng/dL; persistent androgenic symptoms should trigger therapy modification even if a single laboratory value is low. 1
The recommended estradiol range is approximately 200 pg/mL (physiologic premenopausal female levels); supraphysiologic estradiol concentrations (e.g., ≈ 600 pg/mL) increase thromboembolic risk without providing additional testosterone suppression. 1

Increasing estradiol above 2–3 mg daily is discouraged because it raises thromboembolic risk without improving testosterone suppression. 1

Spironolactone provides dual anti‑androgen effects—suppression of testosterone production and blockade of androgen‑receptor binding—making it especially useful for resolving persistent erections despite low serum testosterone. 1
Evidence supports spironolactone dosing up to 400 mg/day for transgender women, with most patients achieving adequate suppression at 100–300 mg/day. 1
Increasing spironolactone to 150 mg twice daily (total 300 mg/day) is recommended to achieve robust testosterone suppression while avoiding the thromboembolic risk associated with supraphysiologic estradiol levels. 1

Re‑evaluate labs 6–8 weeks after increasing spironolactone, aiming for estradiol 100–200 pg/mL, testosterone < 55 ng/dL, and monitor serum potassium to detect hyperkalemia from higher spironolactone doses. 1
Potassium monitoring schedule: obtain a baseline level, repeat 2–4 weeks after the dose change, then every 3–6 months thereafter. 1
Avoid potassium supplements and other potassium‑sparing diuretics while on high‑dose spironolactone to reduce hyperkalemia risk. 1
Dose‑related adverse effects (fatigue, dizziness, hypotension) are less common at 300 mg/day than at doses > 400 mg/day. 1

Assess clinical response at 3 months post‑adjustment; a reduction or resolution of morning erections indicates successful anti‑androgen optimization. 1
Do not rely solely on a low testosterone value (e.g., 4 ng/dL) to judge adequacy of suppression; persistent androgenic symptoms should prompt therapy modification regardless of laboratory results. 1

If spironolactone 300 mg/day fails, consider a GnRH agonist (e.g., monthly goserelin acetate) for more complete testosterone suppression with a low adverse‑reaction profile. 1
Cyproterone acetate 50–100 mg daily is highly effective, achieving female‑range testosterone in ≈ 90 % of patients versus ≈ 19 % with spironolactone in one randomized trial; however, it carries a risk of hepatotoxicity requiring regular liver‑function monitoring. 1