What Are Hormones?
Hormones are your body's chemical messengers. They're made by your glands and enter your bloodstream. There are over 50 types of hormones. As they travel through your body, they control many bodily functions, such as growth, metabolism, reproduction, and mood.
Estrogen and Testosterone
Estrogen and testosterone are sex hormones. Estrogen is often called the female sex hormone, as it plays an important role in the female reproductive system. Likewise, testosterone is referred to as the male sex hormone for the roles it plays in male sexual development and function. It's true that women and people assigned female at birth (AFAB) have much higher levels of estrogen, but they have some testosterone, too.
Estrogen in Women
Estrogen is a class of related hormones that includes estriol, estradiol, and estrone.
- Estriol is made by the placenta. It’s produced during pregnancy.
- Estradiol is the primary sex hormone in premenopausal women and people AFAB. Premenopause is the time from your first period until you enter perimenopause -- the stage just before menopause. Estradiol is formed from developing ovarian follicles. It's responsible for female characteristics and sexual functioning. Estradiol is also important for bone and cardiovascular health.
- Estrone is the main estrogen present during and after menopause.
Estrogen levels rise and fall throughout your life. During puberty, estrogen shoots up to help your body make physical changes, such as breast development. Levels change during your menstrual cycle: rising during ovulation, when your body produces an egg, and dropping during your period. It also falls as you approach and then go through menopause.
Normal estrogen levels
After you start your period, the main type of estrogen in your body (except during pregnancy) is estradiol. Normal levels are:
30 to 400 picograms per milliliter (pg/mL) if you haven’t gone through menopause yet
0 to 30 pg/mL if you’re postmenopausal
Low Estrogen Levels in Women
There are many reasons why your estrogen levels might fall. Some of these include:
Hypogonadism. This condition can cause your ovaries to slow or stop production of estrogen. Some people are born with it; others develop it later due to injury, infection, or other causes.
Hypopituitarism. Your pituitary gland is key to your ovaries making estrogen. When something goes wrong with your pituitary gland, less estrogen is made.
Perimenopause and menopause. During perimenopause (the period before menopause) and menopause, your levels of estrogen (particularly the type called estradiol) drop significantly. This also happens if you have your ovaries removed or damaged before age 40, resulting in early menopause.
Polycystic ovary syndrome (PCOS). This disorder causes cysts on your ovaries, which can trigger menstrual problems and infertility. A variety of hormonal changes occur with PCOS, including low estrogen.
Anorexia nervosa (eating disorder). When you have an eating disorder such as anorexia or bulimia, your body may lose the nutrients it needs to maintain sufficient estrogen.
You may also experience low estrogen if you have been given certain drugs. For example, some types of breast cancer treatment involve blocking estrogen production. And your levels may be low immediately after childbirth and during breastfeeding.
Why are female athletes and athletes AFAB at risk for low estrogen levels?
Women and people AFAB with low body fat often do not make enough of the sex hormones. This can cause their periods to become irregular or stop. They may also develop osteoporosis -- thin bones -- and fractures.
Estrogen Levels and Menopause
Menopause is a natural transition for all women in which their estrogen levels go down. It can also happen abruptly in younger women whose ovaries are removed, resulting in so-called "surgical menopause."
On average, menopause occurs at age 51. When it does, your body produces less estrogen. This can cause uncomfortable symptoms, including:
- Hot flashes
- Night sweats
- Vaginal dryness or itching
- Loss of libido or sex drive
- Moodiness
Lower levels of estrogen may also increase your risk for heart disease and osteoporosis.
High Estrogen Levels in Women
During puberty, it's normal for levels of estrogen to rise. That’s because this hormone fuels changes in a young girl's body. For example, it plays a role in the development of breasts, fuller hips, and pubic and underarm hair. Estrogen levels also rise during a healthy pregnancy.
Other things that can cause high estrogen include:
- Having high body fat
- Having hormone therapy
- Stress
- Drinking too much alcohol
- Liver problems
Symptoms of high estrogen include having irregular periods and dense breast tissue.
High estrogen levels can increase your risk of:
- Breast and ovarian cancers
- Pain from endometriosis
- Insulin resistance
- PCOS
- Uterine cancer
- Tumors on your ovaries and adrenal glands
Testosterone in Women
Testosterone is made by your ovaries and adrenal glands (which are located on top of your kidneys), as well as other tissues and cells in your body. Testosterone can help improve:
- How well your ovaries function
- The strength of your bones
Your body needs a balance of estrogen, testosterone, and other male hormones so that your ovaries can function properly. Researchers also suspect that male hormones can help your brain function better, improving your mood, cognitive abilities, and sex drive.
Normal testosterone levels
Normal levels of testosterone in women are 15-70 nanograms per deciliter (ng/dL) or 0.5-2.4 nanomoles per liter (nmol/L).
Depending on which lab performs your testosterone test, normal values may vary slightly from these. Your health provider can help you understand your test results.
High Testosterone Levels in Women
If your body produces too much testosterone, you may have irregular or absent periods. You may also have more body and facial hair than the average woman. Some women with high testosterone levels develop frontal balding. Other possible effects include acne, an enlarged clitoris, increased muscle mass, and deepening of your voice.
Causes of high testosterone
In women, especially those who haven’t yet gone through menopause, the most common cause of excess testosterone is PCOS.
Other causes of high testosterone include:
- Tumor in the ovaries or adrenal glands
- Congenital adrenal hyperplasia
- Estrogen declining more quickly than testosterone
- Obesity
- Ovary disorders, such as ovarian hyperthecosis
- Medications and supplements, including steroids
- Endocrine disorders such as Cushing's syndrome
Low Testosterone Levels in Women
Low testosterone can be caused by:
- Menopause
- Ovary removal
- Chemotherapy and radiation
- Pituitary gland tumors
- Medications, including contraceptives and corticosteroids
- Illnesses such as Turner's syndrome and Addison’s disease
- Malnutrition
- Genetic anomalies
You may experience some or all of these symptoms from low testosterone in your body:
- Depression or anxiety
- Lowered sex drive
- Weakness and loss of muscle tone
- Fatigue and low energy
- Vaginal dryness
- Menstrual irregularities
- Hair thinning
- Skin dryness
- Insomnia
Takeaways
Your doctor can do a physical examination and assess your health situation and symptoms to determine if further laboratory tests are needed to check hormone levels. Those tests may be important if you have a health condition such as PCOS or have stopped menstruating because of excessive athletic training or anorexia nervosa. If the tests show abnormal levels of hormones, your doctor can prescribe effective treatment.
Testosterone and Estrogen Levels FAQs
What should a woman's estrogen level be?
If you are not in menopause, your estrogen levels should range from 30 to 400 picograms per milliliter. This can be determined with a blood test. Menopausal and postmenopausal women’s estrogen levels are normally much lower: from zero to 30 picograms per milliliter.
What do high levels of estrogen do to a woman?
Too much estrogen can cause your sex drive to drop and your weight to go up, particularly around your waist and hips. You also may experience changes to your periods — with bleeding either lighter or heavier than normal and your cycle’s timing becoming unpredictable. If you have premenstrual symptoms, these can get worse.
What happens when women have low testosterone?
Low testosterone may cause you to feel depressed or anxious, tired, weak, and have less interest in sex. You may find your period becoming irregular, your hair thinning, your skin and vagina drying, and good sleep harder to get.
What does testosterone do for women?
The benefits of testosterone for women include stronger bones, improved ovary function (more regular periods), and possibly a clearer mind, better mood, higher sex drive, and more energy.
