Progesterone
Also known as: Bioidentical Progesterone · Prometrium · Micronized Progesterone · P4
A critical neurosteroid and reproductive hormone that supports sleep, mood, neuroprotection, bone health, and is essential for balancing estrogen in HRT protocols.
Overview
Progesterone is a steroid hormone produced primarily by the corpus luteum after ovulation and by the placenta during pregnancy. Beyond its reproductive functions, progesterone is a potent neurosteroid with significant effects on brain function, sleep architecture, and mood regulation. Micronized bioidentical progesterone (Prometrium) is the preferred form in modern HRT, as synthetic progestins (like medroxyprogesterone acetate) have different receptor binding profiles and risk profiles. In women, progesterone is essential for endometrial protection when using estrogen therapy — it prevents endometrial hyperplasia and reduces cancer risk. But its benefits extend far beyond the uterus: progesterone promotes deep sleep by enhancing GABA-A receptor activity, provides neuroprotection, supports bone formation (stimulates osteoblasts), and has anti-inflammatory and anti-anxiety properties.
In men, progesterone at physiological levels supports brain health, counteracts some effects of excess estrogen, and may support prostate health. It is increasingly recognized as an important hormone for both sexes in optimization protocols.
Mechanism of Action
Binds to progesterone receptors (PR-A and PR-B) to regulate gene transcription. Its metabolite allopregnanolone is a potent positive allosteric modulator of GABA-A receptors, producing anxiolytic and sedative effects. Also modulates mineralocorticoid receptors (anti-aldosterone effect), inhibits 5-alpha reductase, and stimulates osteoblast differentiation.
Key Benefits
Potential Side Effects
Common Stacks
This peptide is commonly combined with the following compounds for synergistic effects:
Known Interactions
The following interactions have been documented for Progesterone. Always consult a healthcare professional before combining compounds.
Synergistic (1)
Standard HRT combination for women. Progesterone balances estrogen's proliferative effects on the endometrium, reducing cancer risk while maintaining hormonal benefits.
Scientific References
Quick Reference
Typical Dose
100-200 mg/day (oral, at bedtime); 50-100 mg (topical cream)
Frequency
Daily at bedtime (oral); cyclical or continuous depending on protocol
Route
Oral (micronized capsule); topical cream; vaginal suppository
Half-Life
~16-18 hours (oral micronized); ~34 hours (vaginal)
Cycle Length
Ongoing as part of HRT; cyclical (days 14-28) or continuous
FDA Status
FDA approved (Prometrium) for secondary amenorrhea and endometrial protection
Need to calculate dosing?
Use our reconstitution calculator to determine exact syringe measurements.
Open CalculatorThis information is for educational purposes only. Consult a qualified healthcare professional before using any peptide. Dosing information reflects commonly reported protocols and may not be appropriate for everyone.
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