Micronized Progesterone

What it is

Micronized progesterone is the bioidentical form of progesterone — the same molecule the ovaries produce after ovulation. The micronized formulation improves oral absorption.

It is structurally distinct from synthetic progestins like medroxyprogesterone acetate, which were used in the original Women's Health Initiative trials and which carry a different risk profile.

How it works

In women with a uterus, progesterone counteracts estrogen's growth effect on the endometrial lining and prevents the increased risk of endometrial cancer that unopposed estrogen would cause.

Taken at bedtime, progesterone's metabolite allopregnanolone acts on GABA receptors and has a calming, sleep-promoting effect for many patients.

Who it's for

• Any woman with a uterus who is taking systemic estrogen
• Patients with significant sleep disruption — bedtime dosing is the workhorse pattern
• Some perimenopausal patients to stabilize cycles and mood

Who should not take it

• Active liver disease
• Known hypersensitivity to peanut oil (some formulations are peanut-oil based)
• Active breast cancer

Common side effects

• Drowsiness — which is why bedtime dosing is preferred
• Mild dizziness in the first weeks
• Breast tenderness, headache

Evidence summary

• NAMS: micronized progesterone is the preferred progestogen for endometrial protection in women on estrogen therapy.
• Multiple trials show meaningful improvement in subjective sleep quality with bedtime micronized progesterone.

FAQ

Sources

• NAMS 2022 Hormone Therapy Position Statement
• ACOG: Menopausal Symptom Management
• U.S. Food & Drug Administration

Symptoms Micronized Progesterone can help treat

Other medications

This page is educational and is not a substitute for a clinical evaluation. Whether any medication is appropriate for you depends on your full medical history. Kindr providers make individualized prescribing decisions during a clinical visit.