HormonesWomen's Health

What is estrogen?

Written by

Lauren Dobischok
26 May, 2023

Medically checked article All HOMED-IQ content is reviewed by medical specialists

Estrogen (also known as oestrogen) is a group of hormones mainly produced in the ovaries of women. There are several types of estrogen, including estradiol, estrone, and estriol. Estrogen plays a critical role in the development and regulation of the female reproductive system and also has effects on other tissues and organs in the body. Estrogen is found not only in women but also in men in smaller amounts.

What is estrogen?

The sex hormone estrogen is one of the steroid hormones that are a part of the endocrine (hormonal) system. As chemical messengers of the body, hormones send signals into the bloodstream and tissues and influence numerous processes in the human body, including sexual function and reproduction (Endocrine Society, 2022). 

What are the functions of estrogen?

Estrogen is generally known as a sex hormone in women, but its functions extend beyond reproduction and are important in both women and men. Understanding the multiple functions of estrogen highlights the importance of this hormone to our overall health and well-being. 

The main reproductive functions of estrogen in women include: 

  • Development of secondary sexual characteristics: During puberty, estrogen increases and is responsible for the development and maintenance of female secondary sexual characteristics, including breast growth, fat distribution, widening of the hips, and pubic hair development. 
  • Regulation of the menstrual cycle: In order for the menstrual cycle to be regular, estrogen works in a delicate balance with other important reproductive hormones, such as progesterone and follicle-stimulating hormone. Estrogen is responsible for the growth of the uterine lining during the menstrual cycle and also promotes ovulation. 
  • Pregnancy: estrogen reaches its peak in the days before ovulation, or when the ovary releases an egg. If fertilization of the egg and pregnancy occurs, estrogen supports the developing fetus and function of the placenta.
  • Menopause: During menopause, estrogen levels drop and ovulation no longer occurs. The drop in estrogen can lead to symptoms such as vaginal dryness, mood swings, night sweats and hot flashes.

In men, estrogen has the following functions: 

  • Sex drive, sperm production, and the ability to get an erection: Estrogen helps modulate sex drive, sperm production, and erectile function in men. Higher than normal estrogen levels in men are linked to erectile dysfunction, lowered sperm count and quality, and lowered sex drive.

Estrogen also has several non-reproductive function in men and women, including:

  • Bone health: Estrogen plays an important role in maintaining bone health. It promotes bone formation and prevents bone resorption, also known as the breakdown of bones. A deficiency of estrogen can lead to an increased risk of osteoporosis (Cheng, 2022). This risk is higher in postmenopausal women as they experience a natural decrease in estrogen.
  • Cardiovascular health: Estrogen has a protective effect on the cardiovascular system by  supporting cholesterol metabolism, dilating blood vessels, and inhibiting inflammation (Knowlton & Lee, 2012). The protective effects of estrogen during the reproductive years are believed to be why women on average develop heart disease later than men (Maas, 2010).
  • Skin quality: Estrogen modulates collagen production, skin moisture, wound healing, and aging. Low estrogen can cause dry, dull, wrinkled, or sagging skin (Thornton, 2013).

Source: Cleveland Clinic, 2022

Where is estrogen produced in the body?

Most estrogen is produced by the ovaries in women and the testes in men. The adrenal glands and adipose tissue (body fat) also secrete estrogen. During pregnancy, the placenta (the organ that allows the exchange of nutrients between parent and fetus) secretes estrogen. Once released, estrogen travels through the bloodstream until it reaches the part of the body that needs to be stimulated into action (Cleveland Clinic, 2022)

The different types of estrogen

Estrogen occurs in the body in four forms. Estrone or E1 is a form of estrogen that the body produces after menopause. Estradiol or E2 is the most common form of estrogen and is found in the body during the reproductive years, such as during puberty. Estriol or E3 is a type of estrogen that everyone produces, but is nearly undetectable in people who aren’t pregnant. Lastly, estetrol or E4 is found only in pregnant women (Endocrine Society, 2022). 

The progression of estrogen levels:

Estrogen levels fluctuate during different stages of life, such as puberty, pregnancy, and menopause. These fluctuations are normal. Estrogen levels naturally increase during puberty and decrease during menopause. It is also normal for estrogen levels to rise during ovulation so that your body can prepare for pregnancy. A drop in estrogen levels occurs during menstruation, when it is not necessary for your body to prepare for pregnancy. Consistently low or high levels of estrogen may indicate an underlying medical condition that needs to be evaluated by a doctor (Cleveland Clinic, 2022).

Changes in estrogen levels 

Why is my estrogen level too low?

It is normal for estrogen levels to fluctuate, but consistently low levels can cause unpleasant symptoms and other health problems. Lowered estrogen is a normal part of aging, but other factors can also cause low estrogen levels. These include eating disorders, genetic conditions, autoimmune diseases, and treatments that affect ovarian function, such as chemotherapy. Changes in the pituitary gland that affect the production of estrogen, as well as primary ovarian failure, also known as premature menopause, can also cause low estrogen levels. In this condition, the ovaries stop producing eggs before the age of 40. Consistently low estrogen levels should be evaluated by a physician to rule out an underlying medical condition (Cleveland Clinic, 2022). 

Symptoms of low estrogen:

  • Infrequent or absent menstrual periods
  • Hot flashes (sudden feeling of warmth) and/or night sweats
  • Difficulty sleeping
  • Dryness and thinning of the skin of the vagina
  • Low mood or trouble concentrating
  • Severe headaches just before your period (menstrual migraines) 

In men: low estrogen levels in men can lead to excess abdominal fat and low sexual desire.

Source: Endocrine Society, 2022

Why is my estrogen level elevated?

Estrogen levels can be elevated if your body produces too much estrogen, you take too much estrogen through medications, or your body does not break down estrogen properly in the body. Multiple factors can contribute elevated estrogen levels: 

  • Medical conditions: Some health conditions are associated with elevated estrogen levels. These include polycystic ovary syndrome (PCOS), uterine fibroids, endometriosis, certain cancers, and insulin resistance. 
  • Medications: Estrogen levels may be elevated due to medications such as hormone replacement therapy. In this case, synthetic forms of estrogen and/or the hormone progesterone are administered to compensate for an estrogen deficiency.
  • Alcohol: Consuming too much alcohol can increase estrogen levels while decreasing the body’s ability to break down estrogen. 
  • Obesity: since fat tissue secretes estrogen, high levels of body fat can lead to increased estrogen levels.
  • Liver dysfunction: the liver plays an important role in the breakdown of hormones, including estrogen. Liver disease or impaired liver function can lead to decreased hormone breakdown and excretion, resulting in elevated estrogen levels.
  • Environmental factors: Exposure to environmental sources of estrogen-like compounds, known as xenoestrogens, such as certain pesticides, plastics, and chemicals, may contribute to higher estrogen levels.

Source: Cleveland Clinic, 2022 ; Martin, 2023

Symptoms of high estrogen:

In women

  • Breast tenderness and swelling
  • Irregular menstrual bleeding – there may be changes in duration, frequency, and intensity
  • Mood swings – irritability and increased anxiety or depression) 
  • Weight gain
  • Fatigue and lack of energy

In men, too much estrogen can lead to enlarged breasts (gynecomastia), erectile dysfunction, and low sex drive. 

Source: Martin, 2023

How can I get my estrogen levels tested? 

If you want to test your estrogen in your doctor’s office or in a laboratory, you will need to provide a blood or urine sample (Medline Plus, 2022). It is also possible to test your estrogen levels from home using a self-test. Homed-IQ’s Hormone Test for Women allows you to test your estradiol level from home, along with other important female hormones. All it takes is a finger prick and a few drops of blood which are then analysed in a certified laboratory. You will receive your test results within a few days within your online Homed-IQ account.

It is important to note that estrogen levels fluctuate throughout the month and that estrogen testing usually needs to be done at a specific moment in the menstrual cycle in order to accurately analyze the results. If you are unsure at which moment to test your estrogen levels, check with your doctor.

What can I do to promote healthy estrogen levels?

A healthy lifestyle can help contribute to healthy estrogen levels. The following tips may help:

  • Eat a balanced diet: Avoiding sugary foods and eating foods high in fiber and healthy fats (fats found in olive oil, nuts, seeds, and fish) can have a positive effect on hormone balance (Cui et al., 2010).
  • Consume red meat in moderation: Studies have suggested that red and processed meats are associated with increased levels of estrogen in the body. Minding your consumption of these foods may support normal estrogen levels (Brinkmann et al., 2010).
  • Reduce your alcohol intake: Alcohol consumption is associated with increased estrogen levels. Alcohol should always be consumed in moderation.
  • Get enough exercise Research has found that exercise is associated with lower estrogen levels and better estrogen regulation (Kossmann et al., 2011). Since adipose tissue secretes estrogen, reducing adipose tissue may be associated with decreased estrogen levels. 
  • Manage stress: Consistently high levels of stress hormones, such as cortisol or adrenaline, is associated with health problems can have a negative impact on estrogen levels. For this reason, it is important to learn healthy ways to manage stress and regulate stress hormone levels

Source: Cleveland Clinic, 2022


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About the author

Lauren Dobischok

Lauren is a health scientist and science communicator currently living in the Netherlands. Originally from Canada, she completed a Research Master’s in Health Sciences at the Netherlands Institute of Health Sciences at Erasmus University Rotterdam (NIHES) with a specialisation in epidemiology. Prior to her master’s degree, she completed a Bachelor’s degree in Health Sciences at Simon Fraser University. With a background in public health, her goal is to create accurate scientific content that is easy to understand and empowers people to make informed decisions. Within Homed-IQ, Lauren works as a Product Developer and Content Lead, working closely with physicians and scientists on medical devices for Homed-IQ’s new products and written communications.