At a glance

Estrogen replacement / HRT
Feminizing hormone therapy
Relief of menopausal symptoms
Blood clot / cardiovascular risk
Cancer risk (breast/endometrial/ovarian)
Blood-pressure increase
Nausea / breast tenderness
BenefitSide effectHealth risk· more & brighter bars = stronger

Effects

  • Estrogen replacement: Replaces estrogen normally made by the body, relieving menopausal hot flushes and symptoms of low estrogen.[7]
  • Feminizing effects: Used as high-dose estrogen in feminizing hormone therapy for transgender women.[3]
  • Gonadotropin suppression: Lowers LH and FSH via negative feedback; this underlies its use in prostate cancer and contraception.[5][3]
  • Symptom onset (hot flushes): When used for hot flushes, improvement is typically reported within 1 to 5 days of an injection.[7]
Classification

Estrogen (estradiol prodrug / ester)

Route

Intramuscular injection or oral tablet[3]

Active half-life

IM in oil ~3.5 days (range 1.2–7.2); oral estradiol terminal ~14–17 h[6][16]

Dosing interval (IM)

Once every 1–4 weeks[3][7]

Clot/cancer risk

Boxed warning: clots, stroke, cancer