Women’s health centre

Normal testosterone and oestrogen 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 oestrogen. Relatively small quantities of testosterone are released into your bloodstream by the ovaries and adrenal glands. In addition to being produced by the ovaries, oestrogen is also produced by fat tissue in the body. These sex hormones are involved in the growth, maintenance, and repair of reproductive tissues. However, 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 behaviour, are significant to both men and women.

The amount and levels of hormones change daily. The sex hormones, oestrogen 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 oestrogen?

Oestrogen is an entire class of related hormones. They include oestriol, oestradiol, and oestrone.

Oestriol is made from the placenta. It?s important only during pregnancy.

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

Oestrone is widespread throughout the body. It is the only one of the oestrogens that?s present in any amount in women after menopause.

Why do oestrogen levels fall?

There are many reasons why oestrogen levels fall, including:

• Hypogonadism (ovarian failure)
• Hypopituitarism (an underactive pituitary gland)
• Pregnancy failure (oestriol)
• The perimenopause and the menopause (oestradiol)
• Polycystic ovarian syndrome (PCOS)
• Anorexia nervosa (eating disorder)
• Extreme exercise or training

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

Why are athletes at risk of low levels of oestrogen?

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 amenorrhoea. They may also develop osteoporosis (thinning of the bones) and fractures as well as other conditions more common in older women after the menopause.