Estrone is one of the three main types of estrogen, a group of hormones that plays a key role in female sexual development and function. The other two types of estrogen are estradiol and estriol.
Estrone is produced primarily in the ovaries and adrenal glands, but also in adipose (fat) tissue. In women of reproductive age, estrone is produced in smaller amounts compared to estradiol, the most dominant estrogen during the reproductive years.
However, after menopause, the ovaries stop producing as much estradiol, and estrone becomes the primary form of estrogen in the body. In fact, it’s often the elevated levels of estrone in postmenopausal women, especially those who are overweight (since estrone is produced in fat tissue), that contribute to the increased risk of estrogen-sensitive conditions like breast cancer after menopause.
Estrone is considered a weaker estrogen compared to estradiol. It binds to estrogen receptors in cells, but it activates them less strongly. This means that its effects on tissues like the breast and the lining of the uterus are less pronounced compared to those of estradiol.
Like all hormones, maintaining the right balance of estrone in the body is important. Too much or too little can contribute to health problems, including menstrual problems, symptoms of menopause, and certain types of cancers.