Normal Testosterone and Estrogen Levels in Women

It may surprise you to know that men don’t have a monopoly on testosterone. Testosterone belongs to a class of male hormones called androgens. But women also have testosterone.

The ovaries produce both testosterone and estrogen. Relatively small quantities of testosterone are released into your bloodstream by the ovaries and adrenal glands. In addition to being produced by the ovaries, estrogen is also produced by fat tissue in the body. These sex hormones are involved in the growth, maintenance, and repair of reproductive tissues. But that’s not all. They influence other body tissues and bone mass as well.

What are hormones?

A hormone is a chemical substance. It’s secreted by one tissue and travels by way of body fluids to affect another tissue in your body. In essence, hormones are "chemical messengers." Many hormones, especially those affecting growth and behavior, are significant to both men and women.

The amount and levels of hormones change daily. The sex hormones, estrogen and testosterone, are secreted in short bursts -- pulses -- which vary from hour to hour and even minute to minute. Hormone release varies between night and day and from one stage of the menstrual cycle to another.

Rightly or not, women are often seen as being under the influence of their hormones. As a result, they are said to be subject to hormonal "tides" or hormonal "storms."

What is estrogen?

Estrogen is an entire class of related hormones. They include estriol, estradiol, and estrone.

Estriol is made from the placenta. It’s important only during pregnancy.

Estradiol is the primary sex hormone of childbearing women. It is formed from developing ovarian follicles. Estradiol is responsible for female characteristics and sexual functioning. Also, estradiol is important to women’s bone health. Estradiol contributes to most gynecologic problems such as endometriosis and fibroids and even female cancers.

Estrone is widespread throughout the body. It is the only one of the estrogens that’s present in any amount in women after menopause.

Why do estrogen levels fall?

There are many reasons why estrogen levels fall, including:

• hypogonadism
• hypopituitarism
• pregnancy failure (estriol)
• perimenopause and menopause (estradiol)
• polycystic ovarian syndrome (PCOS)
• anorexia nervosa (eating disorder)
• extreme exercise or training

Drugs that may decrease levels of estrogen include clomiphene. In addition, women experience low levels of estrogen immediately after childbirth and also during breastfeeding.

Why are athletes at risk for low levels of estrogen?

Women with low body fat often do not produce sufficient amounts of sex hormones. This can be a problem for women such as athletes, models, and gymnasts. It can also be a problem for women with eating disorders. These women can experience a cessation of menstruation, known as amenorrhea. They may also develop osteoporosis -- thin bones -- and fractures as well as other conditions more common in older women after menopause.