Skeletal formula for 17β-estradiol; the primary feminizing hormone in humans.
2.0 – 6.0 mg/d
Estradiol transdermal patch
(New patch placed every 3 – 5 d)
0.025 – 0.2 mg/d
Estradiol valerate or cypionate
5 – 30 mg IM every 2 wk
2 – 10 mg IM every week
Estradot, Estrogel, Progynova, Delestrogen
Estradiol, E2 or Oestradiol, is the most common feminizing hormone used for the treatment of gender dysphoria, and is also the major hormone responsible for puberty in many AFAB people. It may also be prescribed in an esterified form such as "valerate" or "cypionate" to improve resistance to metabolism and thus increase oral bio-availability. In the case of IM injections the esterification process can also help with it's ability to dissolve into fats, and thereby also increase bio-availability.
Estrogen is usually combined with an anti-androgen such as spironolactone or cyproterone acetate, this is because the dosages often required to sufficiently suppress endogenous testosterone through the HPG axis can be dangerous due to the symptoms of high estrogen. Such symptoms of high estrogen can include: migraines, blood clots[footnotes 1], allergies, bloating, fibrocystic breasts, and breast cancer.
↑It should be noted though that a transfeminizing regimen administered according to guidelines has negligible risk of blood clotting, despite many doctors overstating it's risk. This myth may be a remnant of gatekeeping practices used to deny treatment in the presence of other risk factors or as a scare tactic to dissuade potential patients.