Progesterone vs Liothyronine (T3)
A side-by-side research comparison of Progesterone and Liothyronine (T3) across mechanism, dosing, half-life, benefits, side effects and research status.
Comparison table
| Attribute | Progesterone | Liothyronine (T3) |
|---|---|---|
| Full name | Micronized Progesterone (Prometrium) | Liothyronine Sodium (Cytomel) |
| Category | Hormone Replacement | Hormone Replacement |
| Status | FDA Approved | Prescription medication |
| Mechanism | Agonizes progesterone receptors and GABA-A receptors (via allopregnanolone metabolite). Inhibits 5-alpha reductase, opposes estrogen proliferative effects, and promotes myelination in neural tissue. | Binds nuclear thyroid receptors to regulate gene transcription for basal metabolic rate, thermogenesis, protein synthesis, and carbohydrate/fat metabolism in virtually every tissue. |
| Molecular weight | 314.46 Da | 650.97 Da |
| Half-life | ~16-18 hours (oral micronized) | ~2.5 days |
| Bioavailability | ~10% oral (first-pass); ~100% topical/vaginal | ~95% oral |
| Typical dose | 100-200 mg oral or 20-40 mg topical | 5-25 mcg |
| Frequency | Nightly (oral) or daily (topical) | Daily (split AM/PM) |
| Route | Oral capsule, topical cream, or vaginal | Oral tablet or sustained-release capsule |
Progesterone reported benefits
- Enhanced deep sleep (GABA modulation)
- Neuroprotection
- Estrogen opposition
- Reduced anxiety
- DHT reduction (5AR inhibition)
- Cardiovascular protection
Liothyronine (T3) reported benefits
- Metabolic rate increase
- Weight loss support
- Improved energy
- Better mood
- Reduced brain fog
- Enhanced fat oxidation
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Research and educational reference only. Not medical advice.