progesterone + estradiol + estrone + estriol

A combination drug consisting of the four natural steroid hormones **progesterone, estradiol, estrone, and estriol**, all of which are key components of female hormone physiology. This combination is designed to replicate the spectrum of ovarian hormones in hormone replacement therapy (HRT), particularly for postmenopausal women.**Progesterone** acts as a progestogen to counteract the effects of unopposed estrogens on the endometrium, thereby reducing the risk of endometrial hyperplasia. **Estradiol, estrone, and estriol** are all estrogens, acting as agonists at the estrogen receptor, and their role is to alleviate symptoms of estrogen deficiency such as vasomotor symptoms (hot flashes) and vaginal atrophy. Each estrogen has slightly different pharmacokinetics and receptor affinities, which together may more closely mimic the hormonal environment of premenopausal women compared to single-estrogen HRT. The precise clinical efficacy and safety of this four-hormone combination, as opposed to two-hormone combinations (estradiol + progesterone), are not widely documented in large-scale regulatory submissions or guideline-supported products[4][6][7].