Bioidentical hormone

Progesterone (micronized)

Bioidentical progesterone — used alongside estradiol in HRT to protect the endometrium and for sleep, mood, and cycle support.

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

How it works

Micronized progesterone binds progesterone receptors and opposes estrogenic endometrial proliferation. Its metabolites (allopregnanolone) act as GABA-A receptor positive modulators, contributing to its sedative effects.

The evidence

PEPI and subsequent trials established progesterone's endometrial protective role in combined HRT. Cyclic and continuous regimens are both acceptable depending on patient preference and symptoms.

Typical dosing

100 mg/day continuous, or 200 mg/day cyclic (days 1–14 of each calendar month). Taken at bedtime to leverage sedative effect.

Side effects

Common

  • Drowsiness
  • Dizziness on standing

Less common

  • Headache
  • Breast tenderness

Drug interactions

  • CYP3A4 modulators
  • Sedatives — additive sedation