Progesterone Names for HRT
The progesterone used in hormone replacement therapy is called micronized progesterone, with brand names including Prometrium (oral), Crinone (vaginal gel), and Utrogestan/Progestan (oral/vaginal capsules). 1
Specific Formulations
The most commonly referenced progesterone preparations in HRT include:
- Micronized progesterone (MP): The bioidentical form that is "biochemically identical" to endogenous progesterone 1
- Oral formulations: Typically 100-300 mg doses 1, 2
- Vaginal formulations: Including Crinone 4% gel (45 mg daily) and vaginal capsules (100-200 mg) 3, 4
Synthetic Progestins (Not True Progesterone)
It's critical to distinguish natural progesterone from synthetic progestins, which are different compounds:
- Medroxyprogesterone acetate (MPA): 2.5 mg daily in continuous regimens or 10 mg for 12-14 days in sequential regimens - this was used in the WHI trials 5, 1
- Norethisterone acetate (NETA): Transdermal formulation 4
- 17-alpha-hydroxyprogesterone caproate: Injectable form 6
Key Clinical Distinction
Guidelines explicitly recommend FDA-approved preparations that are "biochemically identical" to endogenous progesterone over synthetic progestins when possible, and strongly recommend against custom-compounded hormones. 1 The evidence suggests micronized progesterone may have a more favorable safety profile regarding breast cancer and venous thromboembolism risk compared to synthetic progestins 7, 8, 9.
The choice between oral versus vaginal micronized progesterone depends on patient preference and tolerability, with vaginal administration potentially offering better endometrial protection with fewer systemic side effects 4, 3.