Estrone is a female sex hormone. It is the weakest of the three types of estrogen. Estrogen is one of the two main female sex hormones, along with progesterone. The three types of estrogen include:

* Estrone (E1) continues to be made after menopause when periods stop.
* Estradiol (E2) is the main female hormone throughout most women’s lives.
* Estriol (E3) increases during pregnancy.
After menopause, estrone is the only type of estrogen that your body keeps making naturally. Postmenopausal people usually have higher estrone levels than those who are premenopausal. Men and people designated male at birth also have estrone, but in much lower amounts than people designated female at birth.