Bioidentical hormone

Estradiol

The primary estrogen produced by the ovaries — bioidentical estradiol replacement addresses perimenopausal and menopausal symptoms including hot flashes, sleep disruption, mood, and bone density loss.

Category: Women's health Used in: Estradiol + Progesterone · Estradiol patch

How it works

Estradiol binds estrogen receptors (ERα, ERβ) throughout the body, restoring estrogen signaling lost during perimenopause and menopause. Effects span the central nervous system, vasomotor regulation, bone remodeling, and urogenital tissue.

The evidence

The Women's Health Initiative (WHI) and subsequent re-analyses support estradiol HRT (transdermal preferred for clotting safety) initiated within 10 years of menopause onset for vasomotor and bone outcomes. Transdermal delivery avoids first-pass hepatic metabolism and has a more favorable thrombotic profile than oral estrogens.

Typical dosing

Transdermal patches: 0.025–0.1 mg/day. Oral estradiol: 0.5–2 mg/day. Always paired with progesterone (oral micronized) in patients with an intact uterus.

Side effects

Common

  • Breast tenderness
  • Spotting (early)
  • Bloating
  • Mood changes

Less common

  • Headaches
  • Nausea

Rare

  • Venous thromboembolism (higher with oral)
  • Cholestatic liver effects

Drug interactions

  • CYP3A4 inducers (rifampin, St. John's Wort) — may reduce effect
  • Anticoagulants — adjust monitoring
  • Thyroid replacement — may need dose adjustment