Estrogen in Women: What Is It?

Estrogen is a key sex hormone essential for sexual development and reproductive functioning. 

In the female body, estrogen guides the body through puberty, regulates the menstrual cycle, and supports pregnancy. In the male body, small amounts of estrogen support libido, erectile functioning, and sperm production. 

Estrogen also supports other areas of health, such as:

• Bone health

• Heart health

• Cognitive functioning

• Metabolism 

Read on to learn more about what estrogen does, why it’s essential for fertility, and what to do if your estrogen levels are out of balance. 

Types of Estrogen and Their Functions

Estrone (E1) – The Menopausal Estrogen

Estrone (E1) is considered a weaker form of estrogen. It’s produced by the ovaries and adrenal glands. It’s also produced by adipose (fat) tissue. 

During menopause, estrone becomes the dominant form of estrogen. This is because the body no longer produces estradiol, the ‘stronger’ form of estrogen.

A key feature of estrone is that it can be converted to estradiol as needed. During the reproductive years, this is helpful for regulating the menstrual cycle and preparing the body for fertilization. After menopause, the conversion of estrone to estradiol supports bone and heart health while also providing natural relief from menopause symptoms.

Estradiol (E2) – The Most Potent Estrogen

The strongest form of estrogen, estradiol (E2), is also produced by the ovaries, adrenal glands, and adipose (fat) tissue. 

Estradiol takes the lead during puberty and the reproductive years; guiding key processes related to female growth, development, and fertility. During perimenopause, estradiol levels decline and remain low throughout menopause.

Estriol (E3) – The Pregnancy Estrogen

Estriol (E3) is a specific form of estrogen that is only produced during pregnancy. It’s produced by fetal adrenal glands and the placenta. 

Estriol levels rise as early as two weeks gestation and then peak right before birth. During pregnancy, the role of estriol is to support the growth of the placenta and uterus. Estriol also helps prepare the body for labor, delivery, and breastfeeding. 

Estetrol (E4) – The Fetal Estrogen

Estetrol is another form of estrogen produced during pregnancy. It is exclusively produced by the fetal liver and can be detected from nine weeks gestation. 

The role of estetrol in pregnancy is not fully understood. However, current research suggests that in its synthetic form, estetrol may prove useful in oral contraceptives and hormone replacement therapies (HRTs). 

What Does Estrogen Do? 

Reproduction and Fertility 

In the female reproductive system, estrogen supports: 

• Puberty – helping to define secondary sexual characteristics (such as breasts, hips, and body hair)

• Menstrual Cycle – working with other hormones, such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH), to trigger ovulation

• Libido – helping to boost sex drive, improve mood, and increase natural lubrication during intercourse

• Pregnancy – supporting implantation, placental growth, fetal organ development, labor, and breastfeeding 

Even though estrogen levels are much lower in men compared to women (on average), estrogen still plays a vital role in the male reproductive system. For example, estradiol (E2) helps regulate libido. It also supports erectile functioning and sperm production. If estrogen levels become out of balance, this can lead to excess belly fat, low libido, erectile dysfunction, and in some cases infertility. 

Overall Health and Wellbeing

In addition to supporting the reproductive system, estrogen also supports other aspects of health, including:

• Bones – helping to prevent osteoporosis by maintaining bone density

• Brain – supporting memory, cognition, and mood

• Heart – regulating blood pressure and cholesterol levels

• Metabolism – regulating insulin sensitivity and fat distribution 

• Skin and Hair – supporting collagen production, hydration, and skin elasticity

Estrogen and the Female Body: How Estrogen Levels Fluctuate Throughout Life

Puberty and Adolescence

At the onset of puberty, the brain signals the pituitary gland to begin releasing luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These hormones stimulate the ovaries, which in turn trigger the production of the female hormones estrogen (estradiol) and progesterone. 

This surge in estradiol helps the body develop its secondary sexual characteristics. It also works together with progesterone, LH, and FSH to begin regulating the menstrual cycle. 

It takes the body approximately 2-5 years to transition through puberty to the reproductive years. During this time, hormonal fluctuations are to blame for the many challenges of puberty – such as mood swings, acne, breast tenderness, and body odor. 

Reproductive Years

During the reproductive years, it’s normal for estrogen levels to fluctuate and follow a cyclical pattern. This helps regulate the menstrual cycle. 

Early on in the menstrual cycle, estradiol (E2) levels rise slowly before reaching a peak and then falling right before ovulation. During this time, the role of E2 is to help stimulate ovulation and prepare the body for the implantation of a fertilized egg.

After ovulation, estradiol levels continue to fall before rising again in the mid luteal phase. If pregnancy does not occur, estradiol levels fall again (along with progesterone) and menstruation begins. If a pregnancy does occur, estradiol levels continue to rise to support early pregnancy. 

Perimenopause and Menopause

As the body approaches menopause, estradiol (E2) levels begin to fall. This is a sign that the reproductive era is coming to an end. This transition to menopause (referred to as perimenopause) can last up to eight years.

As estradiol levels decline alongside other hormonal shifts, you may experience the tell-tale signs of menopause – such as hot flashes, mood swings, and insomnia. 

After menopause is reached (i.e. when you haven’t had a period for at least 12 consecutive months), estrone (E1) becomes the dominant form of estrogen in the body. Low estradiol (E2) levels are to blame for the increased risk of osteoporosis, cardiovascular disease, and cognitive decline after menopause. 

Pregnancy

Following implantation, estradiol (E2) levels increase to support early pregnancy. By two weeks gestation, estriol (E3) levels also rise to support the growth of the placenta, uterus, and mammary glands. Estetrol (E4) levels can also be detected at nine weeks gestation.

Estrogen Imbalance: Causes, Symptoms, and Risks

High Estrogen (Estrogen Dominance)

Sometimes, estrogen levels can be too high. This is often referred to as ‘estrogen dominance’.

Common symptoms of estrogen dominance include:

• Bloating

• Breast tenderness

• Difficulty getting pregnant

• Irregular periods

• Low libido

• Mood swings

• Weight gain

One of the most common conditions associated with estrogen dominance is polycystic ovary syndrome (PCOS). PCOS is one of the leading causes of infertility, and it affects an estimated 6-13% of women of reproductive age. 

Treatment for PCOS typically aims to address hormone imbalance by regulating ovulation. This can help increase progesterone levels and decrease relatively high estrogen levels. Depending on your fertility goals, treatment may include a combination of lifestyle changes, medications, and supplements (such as Mira’s own PCOS supplements). 

In addition to PCOS, other factors can lead to estrogen dominance. This includes: 

• Excess body fat

• Environmental toxins (such as heavy metal pollution and BPA plastics)

• Stress

• Tumors

If left untreated, long-term estrogen dominance can increase the risk of certain health conditions, such as:

• Autoimmune diseases

• Blood clots and stroke 

• Breast, ovarian, and uterine cancer

• Endometriosis

• Uterine fibroids and polyps

If you suspect your estrogen levels are too high, it’s worth speaking with your doctor. They can evaluate your symptoms, run tests to check your estrogen levels, and provide guidance on treatment. 

Low Estrogen

It’s also possible for estrogen levels to be too low. 

Naturally, this occurs during the transition to menopause when estradiol (E2) levels decline. 

Common low estrogen symptoms due to menopause include:

• Hot flashes

• Night sweats

• Vaginal dryness

• Mood swings and irritability

After menopause, estradiol levels remain low. This increases the risk of osteoporosis, stroke, heart disease, and weight gain. A combination of hormone replacement therapy (HRT), supplements, and lifestyle changes can help mitigate these risks. 

In addition to menopause, excessive exercise, eating disorders, and ovarian failure can also lead to low estrogen levels.

Estrogen Testing: How to Measure Your Hormone Levels

Blood Testing

The most straightforward way to test for estrogen is with a blood test at your doctor’s office.

Testing estrone (E1) and estradiol (E2) levels in blood can be helpful for:

• Assessing reproductive health and fertility

• Monitoring HRT and infertility treatments

If you are pregnant, estriol (E3) blood testing can also help monitor high-risk pregnancies. 

Urine Testing

It’s also possible to test your estrogen levels in urine with the help of advanced hormone monitoring systems (like the Mira Monitor and Mira App). These tools offer a more convenient and cost-effective way to test your estrogen levels on a regular basis. 

This is particularly helpful if you are: 

• Actively planning a pregnancy

• Monitoring a hormone condition, such as PCOS

• Anticipating hormonal changes ahead of menopause

• Monitoring the impact of HRT with your healthcare provider

Urine estrogen testing works by measuring the urine metabolite of estradiol (E2), known as estrone-3-glucuronide (E3G), which correlates to your E2 levels. Urine samples can be taken and analyzed at home, allowing for real-time testing and monitoring.

To learn more about how Mira can help you navigate your fertility and reproductive health, visit How Mira Works.

Saliva Testing

Another way to test for estrogen is with a saliva test. In most cases, saliva tests are used to check for estrogen dominance and low estrogen levels. The process of testing involves taking a saliva sample at home and then sending it to a laboratory. 

Although saliva testing is the most affordable option, it is also the least accurate, and results can vary depending on the laboratory.

Factors That Affect Test Results

When testing your estrogen levels, it’s important to be mindful of the following factors that can interfere with your results: 

• Menstrual Cycle – estrogen levels are typically highest right before ovulation.

• Pregnancy – estrogen levels rise dramatically during pregnancy and remain elevated until delivery.

• Menopause – estrogen levels decline during perimenopause and remain low after menopause is reached. 

• Medications – certain medications, such as hormonal birth control, HRT, steroids, antibiotics, and biotin can interfere with estrogen levels.

• Lifestyle – exercise, diet, and alcohol consumption can interfere with estrogen levels.

If you are concerned about your estrogen test results, speak with your doctor. They can help you better understand your results and how your age, medications, and lifestyle may interfere with your estrogen levels. 

Treating Estrogen Imbalance

Hormone Replacement Therapy (HRT)

If estrogen levels are low, hormone replacement therapy is an option.

One common example of this is estrogen supplements, which are a synthetic form of estradiol often used to ease symptoms of menopause. Combination therapies are also common and typically include a combination of estrogen and progestin (the synthetic form of progesterone).

Many HRTs come with a risk of blood clots, stroke, and cancer. It’s important to speak with your doctor before starting an HRT or supplement – even if it can be purchased over the counter. 

Phytoestrogen-Rich Foods

Certain foods contain natural compounds very similar to estrogen. When consumed, these compounds mimic the effects of estrogen. This, in turn, can help promote overall hormone balance.

Common phytoestrogen-rich foods to incorporate into your diet include:

• Apples

• Carrots

• Celery

• Chaste berries

• Flaxseeds

• Garlic

• Pomegranates

• Potatoes

• Red clover

• Rice

• Soybeans

• Sweet potatoes 

• Wheat

Dietary Supplements

Certain supplements can also help balance your overall hormone levels, including estrogen levels. 

For example, doctors sometimes recommend black cohosh, ginseng, and red clover to ease menopause symptoms. Myo-inositol and D-chiro-inositol can also be used together as a supplement to treat PCOS-related hormone imbalance. 

If you are actively trying to conceive (TTC), prenatal supplements (such as Mira’s own prenatal multivitamins) can also promote hormone balance while preparing the body for pregnancy. 

Lifestyle

In general, maintaining a healthy lifestyle can also help to keep your estrogen levels (and overall hormone levels) in balance. This includes:

• Exercising regularly (the CDC recommends getting at least 150 minutes of exercise each week)

• Maintaining a healthy weight

• Keeping stress levels low

• Getting plenty of sleep (the CDC recommends getting at least 7 hours of sleep daily)

Final Thoughts

From ovulation to delivery, it’s clear that life itself would not be possible without estrogen. 

When estrogen levels are in balance, the body benefits from:

• Increased fertility

• Regulated metabolism 

• Improved cognitive functioning

• Healthier skin and hair

• Reduced risk of osteoporosis and heart disease

If you suspect that your estrogen levels are out of balance, it’s important to get your hormones tested – especially if you are actively TTC, approaching the age of perimenopause, or experiencing symptoms of hormone imbalance. 

Frequently Asked Questions

Do men have estrogen?

Yes, men have estrogen. However, levels are much lower compared to women. In men, estrogen helps enhance libido while also supporting erectile functioning and sperm production. 

What are the effects of high estrogen on women?

High estrogen levels can lead to irritability, mood swings, bloating, irregular periods, and an increased risk of cancer and endometrial hyperplasia.

What are the effects of low estrogen levels in women?

Low estrogen can lead to hot flashes, nausea, night sweats, increased risk of stroke, heart attack, and osteoporosis.

What level of estradiol is normal?

For women of reproductive age, estradiol levels typically range from 15-350 pg/mL. 

How much estrogen does a woman’s body produce per day?

Estrogen levels fluctuate depending on age and menstrual cycle phase. However, on average, researchers estimate the female body produces 70-500 mcg of estradiol daily.

How can a woman raise her estrogen levels naturally and safely?

The best way to balance estrogen levels is by maintaining a healthy lifestyle and incorporating phytoestrogen-rich foods into your diet. You should also speak to your doctor about hormone replacement therapy (HRT). 

What are high estrogen symptoms?

Common symptoms of estrogen dominance include:

• Weight gain

• Bloating

• Mood swings

• Irregular periods

• Breast tenderness

• Difficulty getting pregnant