Estrogen: Hormone, Function, Levels & Imbalances (2023)

Overview

What is estrogen?

Estrogen is one of two sex hormones commonly associated with people assigned female at birth (AFAB), including cisgender women, transgender men and nonbinary people with vaginas. Along with progesterone, estrogen plays a key role in your reproductive health. The development of secondary sex characteristics (breasts, hips, etc.), menstruation, pregnancy and menopause are all possible, in part, because of estrogen.

Estrogen plays an important role in other body systems, too. For this reason, although AFAB people have the most estrogen, all genders make this hormone.

What are the types of estrogen?

There are three major forms of estrogen:

• Estrone (E1) is the primary form of estrogen that your body makes after menopause.
• Estradiol (E2) is the primary form of estrogen in your body during your reproductive years. It’s the most potent form of estrogen.
• Estriol (E3) is the primary form of estrogen during pregnancy.

Function

What role does estrogen play in reproductive health for women or DFAB?

Estrogen, like all hormones, is a chemical messenger. It tells your body when to start and stop processes affecting your sexual and reproductive health. These processes cause important changes in your body.

Puberty

Estrogen levels rise during puberty. The increase leads to secondary sex characteristics like breasts and changes in overall body composition (like curves).

Menstrual cycle

Along with hormones made in your brain (FSH and LH) and progesterone, estrogen plays an important part in your menstrual cycle. These hormones coexist in a delicate balance to keep your periods regular. Estrogen plays a role in ovulation (when your ovaries release an egg) and thickens the lining of your uterus (endometrium) to prepare it for pregnancy.

Pregnancy & Fertility

Estrogen peaks in the days leading up to ovulation. This is your most fertile period. At the same time, estrogen thins your cervical mucus, a fluid sperm has to swim through to reach and fertilize an egg. These estrogen-induced changes make it easier for you to become pregnant if you have intercourse.

Regardless of where you are in your menstrual cycle, the presence of estrogen makes it more comfortable to have intercourse. It keeps your vaginal walls thick, elastic and lubricated, reducing pain associated with penetrative sex.

Menopause

Estrogen levels drop during perimenopause, the time right before menopause. Perimenopause may last several years before menopause. Menopause officially begins when you don’t have a period for 12 months. It usually happens around age 51. With menopause, your estrogen levels drop and you no longer ovulate. The decrease in estrogen may lead to symptoms like vaginal dryness, mood changes, night sweats and hot flashes.

The primary estrogen in your body changes from estradiol (E2) to estrone (E1) during menopause.

What role does estrogen play in reproductive health for men or AMAB?

Estrogen affects the reproductive health of people who are assigned male at birth (AMAB), too. In cisgender men, transgender women and nonbinary people with penises, estrogen impacts sex drive and the ability to get an erection and make sperm.

Too little estrogen can lead to a low sex drive. Too much of it can cause infertility and erectile dysfunction. Excessive estrogen can cause gynecomastia, or enlarged breasts.

If you’re assigned male at birth and concerned about your estrogen levels, speak with an endocrinologist or a functional medicine specialist for help.

What is the non-reproductive function of estrogen?

Estrogen regulates important processes in your skeletal, cardiovascular, and central nervous systems that impact your overall health. Estrogen affects:

• Cholesterol levels.
• Blood sugar levels.
• Bone and muscle mass.
• Circulation and blood flow.
• Collagen production and moisture in your skin.
• Brain function, including your ability to focus.

Anatomy

Where is estrogen located in the body?

Your ovaries make most of your estrogen during your reproductive years. Your adrenal glands (the glands on your kidneys) and adipose tissue (body fat) secrete estrogen, too. The placenta (the organ that allows nutrient-sharing between parent and fetus) secretes estrogen during pregnancy.

Once it’s released, estrogen travels through the bloodstream until it reaches the part of your body that needs to be spurred into action. There, estrogen binds to a protein, called an estrogen receptor, that gets the process moving. Estrogen receptors are located throughout your body.

Conditions and Disorders

What are the common conditions and disorders associated with estrogen?

Estrogen plays a role in most conditions that fall under the umbrella of women’s health. Some of the most common include:

• Anorexia nervosa: Conditions like anorexia nervosa are associated with low estrogen levels. Too little estrogen can cause irregular and missed periods (amenorrhea). People with very little body fat (models, athletes) or engage in disordered eating may also have low estrogen.
• Breast cancer: Studies have shown that increased exposure to estrogen does not increase breast cancer risk, but it may worsen breast cancer once it’s formed.
• Endometriosis: Estrogen doesn’t cause endometriosis, but estrogen may worsen endometriosis pain.
• Female sexual dysfunction (FSD): Falling estrogen levels can cause physical and emotional changes that make sex less enjoyable. However, estrogen is not considered for hormone replacement until you’re menopausal.
• Fibrocystic breasts: Fluctuating estrogen levels during your menstrual cycle may make your breast tissue feel lumpy, tender or uncomfortable.
• Infertility: Low and high estrogen can disrupt your menstrual cycle. Underlying causes that can lead to low and high estrogen may be associated with infertility.
• Obesity: Estrogen levels are often higher among people with more body fat.
• Osteoporosis: Low estrogen levels can weaken your bones so that they fracture and break more easily.
• Polycystic ovary syndrome (PCOS): PCOS is a condition that occurs when the ovaries produce too many androgens (hormones associated with being assigned male at birth). Sometimes with PCOS, estrogen levels are too high in relation to progesterone levels.
• Primary ovarian insufficiency (also known as premature menopause): With this condition, the ovaries prematurely stop producing eggs (before age 40). As a result, your ovaries don’t secrete the estrogen your body needs.
• Premenstrual syndrome (PMS) and Premenstrual dysphoric disorder (PMDD): The cyclical hormone changes associated with menstruation can lead to unpleasant physical symptoms and mood changes. Dips in estrogen following ovulation are a potential cause of PMS and PMDD.
• Turner Syndrome: Ovaries are often underdeveloped in Turner syndrome, resulting in low estrogen. As a result, people with this condition may not develop breasts or get their periods.
• Uterine cancer (endometrial cancer): High estrogen levels may cause the lining of your uterus to build up. Eventually, cancer cells may start to grow.
• Uterine fibroids and polyps: Too much estrogen may be associated with noncancerous tumors called fibroids or polyps that grow in your uterus.
• Vaginal atrophy (atrophic vaginitis): Too little estrogen may cause the lining of your vagina to thin and become dry. Vaginal atrophy is most common during menopause and postmenopause.

Research is ongoing about estrogen's role in conditions affecting other body systems. For instance, estrogen has been linked to some endocrine disorders and gastrointestinal diseases.

What are normal estrogen levels?

Estrogen levels rise and fall throughout life. The fluctuation is normal. For instance, it’s normal for estrogen levels to rise during puberty and decline as you approach menopause. It’s normal for estrogen levels to rise during ovulation so that your body can prepare itself for pregnancy. It’s normal for levels to dip during your period when the pregnancy changes aren’t needed.

Levels that are consistently low or high may signal an underlying condition that requires your provider’s attention.

What happens when estrogen levels are consistently low?

Low estrogen is often a tell-tale sign that you’re approaching menopause. Low estrogen may also signify a fertility problem, a nutritional deficiency, a condition like Turner syndrome, etc.

Symptoms may include:

• Breast tenderness.
• Weak or brittle bones.
• Hot flashes and night sweats.
• Irregular periods or no periods.
• Headaches, trouble concentrating.
• Fatigue, drowsiness, trouble sleeping.
• Mood changes, irritability and depression.
• Vaginal dryness, leading to painful intercourse (dyspareunia).

What happens when estrogen levels are consistently high?

Excess estrogen in your body can be associated with multiple conditions: polyps, fibroids, PCOS, endometriosis pain, ovarian tumors, etc.). Your levels may be high because you have too much estrogen in relation to your other sex hormone, progesterone. Medications you’re taking that contain estrogen may cause you to have too much of it in your body.

Symptoms may include:

• Decreased sex drive.
• Weight gain, especially in your waist and hips.
• Irregular periods (unpredictable timing, light or heavy bleeding).
• Worsening symptoms associated with PMS or PMDD.

How do I know my estrogen level?

An estrogen test can measure your levels of estrone (E1), estradiol (E2) or estriol (E3). Your provider will do a simple blood draw and send it to a lab for analysis.

What are common treatments for estrogen-related conditions?

Hormone replacement therapy (HT) is a common treatment for low estrogen, especially for people experiencing menopause. With HT, your provider prescribes small doses of estrogen to boost your level or a combination of estrogen and progesterone (or the synthetic version of progesterone, progestin). HT comes with risks, though, and isn’t for everyone. Talk to your provider about whether you’re a good candidate for HT.

Care

How can I maintain healthy estrogen levels?

You can’t always prevent the conditions associated with hormone imbalances. Still, you can put good practices into place to help maintain your overall health.

• Get enough sleep. Getting adequate, uninterrupted sleep each night helps your body maintain the healthy hormone levels needed to carry out important functions.
• Manage your stress. High stress can cause your body to produce too much of the stress hormones cortisol and adrenaline. Excess stress hormones can cause a hormone imbalance that negatively impacts your estrogen levels.
• Get the right amount of exercise. A healthy amount of exercise can help you regulate how much you eat and how much body fat you have. It can help you sleep better, too.
• Limit your alcohol intake. Alcohol can raise your estrogen levels. Over time, too much exposure to estrogen may raise your cancer risk.
• Practice good eating habits. Monitor your food intake to help balance your hormones. Reducing foods with sugar and eating foods high in fiber and healthy fats (fats found in olive oil, nuts, seeds and fish) can help with hormone balance.

A note from Cleveland Clinic

Estrogen is an essential part of your reproductive health — and your overall health for that matter. It’s natural for estrogen levels to vary depending on your age and menstrual cycle. If they’re consistently high or low, you may experience unpleasant symptoms worth discussing with your provider. Treatments are available that can help, most often in the form of contraception, lifestyle modifications or hormonal therapies after menopause.