From the Guidelines
Hormone therapy for feminization in male-to-female transgender individuals should be initiated with estradiol at a dose of 2-6 mg daily, in combination with an anti-androgen such as spironolactone, to achieve optimal feminization while minimizing adverse effects. The optimal dosage of hormone therapy for feminization is not clearly established, but most individuals achieve oestradiol and testosterone concentrations in the cisgender female reference range with this regimen 1. The therapy involves oestradiol therapy and anti-androgen medications, such as spironolactone, cyproterone acetate, bicalutamide, finasteride, or gonadotropin-releasing hormone analogues, to help trans women and non-binary individuals develop a more feminine appearance 1. Some key points to consider when initiating hormone therapy for feminization include:
- Starting with lower doses and gradually increasing based on hormone level monitoring and physical changes
- Monitoring blood tests every 3 months initially, then every 6-12 months once stable, aiming for estradiol levels of 100-200 pg/mL and testosterone below 50 ng/dL
- Potential side effects, such as blood clots, liver problems, and mood changes, and taking steps to minimize these risks
- Tailoring the therapy to individual health factors, especially considering cardiovascular risk factors, liver function, and personal transition goals 1. It is essential to note that some physical characteristics induced by prior male puberty do not change with feminizing gender-affirming hormone therapy, such as lowered voice pitch, laryngeal prominence of the thyroid cartilage, and bone structure 1. Adverse effects of feminizing hormone therapy include an increased risk of venous thromboembolism, weight gain, compromised bone structure, infertility, and cardiovascular disease relative to cisgender women and men 1.
From the Research
Hormone Therapy Dosage for Feminization in Male-to-Female Transsexuals
- The most common treatment regimen for male-to-female transsexuals is a combination of ethinyl oestradiol and cyproterone acetate, with the exception of transdermal oestradiol-17beta in individuals over the age of 40 2.
- A study found that treatment with monthly injections of gonadotropin-releasing hormone agonist (GnRHa) and oral oestradiol-17beta valerate for 2 years achieved feminization and was well accepted by patients, with significant declines in gonadotropins, total testosterone, and calculated free testosterone 2.
- The use of spironolactone, an antiandrogen, has been studied in the context of female hyperandrogenism, but its effects on hormone levels in male-to-female transsexuals are not well understood 3, 4, 5.
- A systematic review found that antiandrogens, including cyproterone acetate and spironolactone, may increase prolactin levels in transgender women on estrogen therapy, but the effects of antiandrogens on hyperprolactinemia and prolactinomas are unclear 4.
- Drospirenone, a novel progestin with antiandrogenic activity, has been used in combined oral contraceptives and menopausal hormonal therapy, but its use in male-to-female transsexuals has not been studied 6.
Side Effects and Complications
- Common side effects of hormone therapy in male-to-female transsexuals include venous thrombosis, elevated liver enzymes, symptomatic gallstones, hyperprolactinaemia, and depression 2.
- The use of GnRHa and oestradiol-17beta valerate was found to have a lower rate of side effects and complications compared to traditional hormone therapy regimens 2.
- Spironolactone may have antagonistic effects on androgen receptors, but its effects on body composition and sex hormone levels are not well understood 5.