Benefits of Progesterone.
Non-clinical studies of progesterone.
Progesterone is a steroid hormone that is essential for the regulation of reproductive function. Progesterone has been approved for several indications including the treatment of anovulatory menstrual cycles, assisted reproductive technology, contraception during lactation and, when combined with estrogen, for the prevention of endometrial hyperplasia in postmenopausal hormonal therapy. In addition to its role in reproduction, progesterone regulates a number of biologically distinct processes in other tissues, particularly in the nervous system. This physiological hormone is poorly absorbed when administered in a crystalline form and is not active when given orally, unless in micronized form, or from different non-oral delivery systems that allow a more constant delivery rate. A limited number of preclinical studies have been conducted to document the toxicity, carcinogenicity and overall animal safety of progesterone delivered from different formulations, and these rather old studies showed no safety concern. More recently, it has been shown in animal experiments that progesterone, its metabolite allopregnanolone and structurally related progestins have positive effects on neuroregeneration and repair of brain damage, as well as myelin repair. These recent preclinical findings have the potential to accelerate therapeutic translation for multiple unmet neurological needs.
Progesterone for treatment of symptomatic menopausal women.
This review’s purpose is to highlight evidence that oral micronized progesterone (progesterone) is effective for hot flushes and night sweats (vasomotor symptoms, VMS), improves sleep and is likely safe in menopausal women (who are more than 1 year since last menstruation). Methods include randomized controlled clinical trials (RCT) supplemented with basic science, population and observational data as needed. The barrier to use of progesterone is lack of awareness that safety concerns with estrogen-including ‘menopausal hormone therapy’ (MHT) are not applicable to progesterone. In a single 3-month RCT, progesterone (300 mg at bedtime) was effective treatment of VMS in 133 healthy menopausal women. It caused an overall 55% VMS decrease, no withdrawal-related VMS rebound and a greater VMS decrease in 46 women with ≥50 moderate-intense VMS/week. Progesterone is equally or more effective than estradiol in improving cardiovascular endothelial function and caused no cardiovascular safety concerns in a 3-month RCT. An 8-year prospective cohort study (E3N) in more than 80 000 menopausal women showed progesterone prevented breast cancer in estrogen-treated women. Multiple RCTs confirm that progesterone (300 mg daily at bedtime) does not cause depression and improves deep sleep. In conclusion, progesterone effectively treats VMS, improves sleep and may be the only therapy that symptomatic women, who are menopausal at a normal age and without osteoporosis, need.