Estrone (E1)

Estrogens are a group of hormones that play a key role in female reproductive health, including puberty, menstruation, pregnancy, and menopause. However, estrogens are also important for more general bodily functions in both males and females, including healthy cholesterol and blood sugar levels, bone and muscle strength, and brain functions such as the ability to focus.

There are many types of estrogen, but only three types are commonly tested. Estrone (E1) is the weakest of the three, made mostly by body fat and the adrenal glands in males and females; in females, the ovaries also make estrone, and estrone is the only type of estrogen that females continue to make after menopause. Estradiol (E2) is the main estrogen in nonpregnant females of childbearing age. Estriol (E3) is an estrogen that increases during pregnancy.

Most of your estrone is created when other hormones (such as androstenedione) are converted in body tissues, especially fat tissue. That's one reason people who carry more body fat tend to have higher estrone levels.

Though estrogen levels depend on many factors, including sex and age, levels that stay too high or too low may be a sign of a health problem.

A healthy level of estrogen depends on several factors, including your age, your sex, the reasons for having the test, the type of estrogen that was measured, and the results of other tests you may have had.

Estrogen levels in males don't change much throughout life. Therefore, a high level is usually a sign of a health condition such as infertility or an estrogen-producing tumor.

In females, however, estrogen levels change a lot. They rise during puberty, are at their highest during pregnancy, and decline after menopause. Because estrogen levels change so often, you may need to be tested more than once to look for a trend in your estrogen levels over time. In women, comparing estrone with estradiol can sometimes help your provider assess menopausal status.