What is Estrogen Dominance?

When searching for information about hormone imbalances, it is likely you’ll come across the term Estrogen Dominance.


What is Estrogen Dominance?

Estrogen dominance has emerged as a buzzword over the past ten years, and is used to describe a common hormonal imbalance among women. It should be noted that estrogen dominance is not a medical diagnosis, but rather an umbrella term that encompasses the symptoms that occur when estrogen is elevated relative to progesterone – it’s balancing counterpart. While estrogen dominance is not a standalone condition, it is a pattern that many functional medicine practitioners observe in practice.


Understanding Estrogen and its Metabolites

Estrogen is a group of hormones that are important for our menstrual health and fertility, protects our bones and supports cognitive health. It is the hormone that keeps us feeling youthful and sexy. While having adequate estrogen levels are important, too much estrogen can cause issues.

The symptoms of estrogen dominance in women and people who menstruate include:

  • Short or irregular menstrual cycles
  • Painful periods
  • Mood swings and irritability
  • Cyclic breast tenderness
  • Heavy periods
  • Breast cysts
  • Anxiety
  • Weight gain


For men:

  • Enlarged breasts
  • Sexual dysfunction
  • Infertility


Why Does This Happen?

The truth is: there is not one single cause of estrogen dominance, there are multiple. These include:

  • Poor estrogen metabolism
  • Gut dysbiosis (an imbalance between the healthy and bad bacteria in your gut)
  • Low fibre diet
  • Alcohol consumption
  • Elevated estrogen exposure
  • Obesity
  • Low progesterone
  • Perimenopause


Let’s explore these further…


Poor Estrogen Metabolism

Estrogen is produced in the adrenal glands and fat tissue, as well as the ovaries in women and the testes in men. In women and people who menstruate, there are three different types of estrogen:

  • Estrone (E1): Is considered to be a weak estrogen. It is produced mostly in body fat, but also in the placenta and ovaries.
  • Estradiol (E2): This is the most potent and active of the estrogens. It is made in the ovaries, and in lesser amounts from DHEA/testosterone. It binds very strongly to estrogen receptors, and is the main estrogen involved in the menstrual cycle.
  • Estriol (E3): Estradiol can be converted to estriol, predominantly in the liver. Estriol is a weak estrogen. It is the main estrogen of pregnancy, and is secreted by the placenta.


Our total estrogen exposure is not only determined by the production of the aforementioned estrogens, but also by the breakdown into their different metabolites. 

Estrogen is metabolized in the liver through three pathways into 2-hydroxyl, 4-hydroxyl and 16-hydroxyl estrogen. This is known as phase I of estrogen metabolism.

The 2-hydroxyl metabolite pathway is considered the best, as it creates a weak metabolite that has the lowest risk for cancer. The other two pathways, the 4-hydroxyl and 16-hydroxyl metabolite pathway, produce more potent estrogenic metabolites and are associated with a higher risk of breast cancer. 1, 2

When your body is diverting more of the estrogen down the 4-hydroxyl and 16- hydroxyl pathway, this can cause symptoms consistent with estrogen dominance: heavy menses, PMS and irritability.


Gut Dysbiosis

After your hormones are metabolized in the liver, some of the estrogen (known as conjugated estrogen) is excreted into the bile and dumped into the small intestine. The bacteria in your gut (the microbiome) play an important role in regulating circulating estrogens.

These estrogen-metabolizing bacteria are referred to as the “estrobolome”, and they secrete an enzyme called beta-glucuronidase which breaks down the conjugated estrogen, allowing estrogen to be reabsorbed by the gut and delivered into the bloodstream. 3 If there is an imbalance in the gut bacteria (referred to as dysbiosis), there can be an abundance of β-glucuronidase producing bacteria, which leads to elevated levels of circulating estrogens. Therefore, when investigating hormonal imbalances, it’s imperative to take gastrointestinal health into consideration.


Low Fiber Diet

Fiber is essential for gut health. It helps to normalize bowel movements and to support the gut microbiome. Increased fibre has been shown to reduce circulating estrogens, presumably by reducing beta-glucaronidase activity and the reabsorption of estrogen. 4  

The current recommendation is for individuals to consume between 21 – 30 grams of fibre per day dependent on their age 5, and yet a national consumption survey in the United States showed that only 5% of the American population were meeting these recommendations. 6 Consuming adequate fibre in your diet is perhaps one of the simplest ways to improve both gut health and to support hormone metabolism. For perspective, 1 cup of broccoli contains 5 grams of fibre, 1 apple contains 4.5 grams of fibre, 1 cup of oatmeal (instant) contains 5 grams of fibre, and 1 cup of cooked black beans contains 15 grams of fibre.



Alcohol consumption has been shown to increase estradiol levels. 7 This may in part explain the negative impact alcohol can has on menstrual cycle health.  Long-term alcohol use is associated with decreased ovarian reserve and an increase in ovarian oxidative stress. 8

When assessing hormonal health, it’s important to acknowledge alcohol consumption can play a detrimental role.


Elevated Estrogen Exposure

We live in a toxic world, where we are exposed to multiple chemicals on a daily basis. Some of these chemicals are called endocrine-disrupting chemicals (EDC’s) (https://www.endocrine.org/topics/edc), and are commonly found in the pesticide, herbicides and fungicides used on our conventional fruits and vegetables. Furthermore, according to the Environmental Working Group (EWG) (hyperlink: https://www.ewg.org/), personal care products are manufactured with 10,500 unique chemical ingredients, many of which are known to be EDC’s. While these chemicals may only exist in small quantities in our food or our personal care products, we store them in fat tissue, which lends them to have a cumulative effect. 9

Some of these EDC’s have estrogenic activity, which means that they mimic the estrogen found in our body. Counterintuitive, many of these EDS cause their greatest amount of endocrine disruption at small or moderate concentrations, rather than high amounts. 10 The true impact of these chemicals and the combination of chemicals on our reproductive and hormone health is not fully understood. It is an area that deserves further investigation, as EDC’s are prolific in our food systems, personal care products and lives.  



Obesity is known to increase the risk of endometrial and breast cancer among post-menopausal women. 11 This association may be explained by the higher levels of estrogen seen in post-menopausal women with a higher body-fat percentage.

Adipose (fat) tissue is the major site where androgens (commonly labelled as “male sex hormones”) are converted to estrogen (estrone) via the aromatase enzyme. With excess adipose tissue, there is an increase in the conversion of androgens to estrone, leading to amplified estrogenic activity. 11 Increased conversion of androgens to estrogen can also be caused by elevated inflammation.


Low Progesterone

If progesterone levels are low, then estrogen is left unchecked. This can result in symptoms of excess estrogen, particularly irregular periods, long or heavy periods and anxiety.

There are multiple causes of low progesterone, which include:

  • Chronic Stress 12
  • Hypothyroidism 13
  • PCOS (polycystic ovarian syndrome)
  • Perimenopause


Perimenopause is one of the most common causes of low progesterone, and yet, often overlooked. During perimenopause, there is a progressive decline in progesterone levels, while estradiol fluctuates. This causes episodes of elevated estrogen and low progesterone, triggering irregular and shorter cycles, and mood swings.


How To Determine If You Have Estrogen Dominance

If you suspect that you may be experiencing symptoms of estrogen dominance, it is important to investigate with a health-care provider. The multiple causes of estrogen dominance further underline the need for individualized care. 

This starts with identifying WHY you’re experiencing these symptoms. Is it poor estrogen metabolism? Is it PCOS? Is it exposure to endocrine disruptors? Is it perimenopause? Certain conditions should be ruled out, or diagnosed and treated.

The functional medicine approach to addressing estrogen dominance starts with identifying the root cause, using comprehensive testing, and building a plan to balance hormones and restore function within the body.





  1. Miao, S., Yang, F., Wang, Y., Shao, C., Zava, D. T., Ding, Q., & Shi, Y. E. (2019). 4-Hydroxy estrogen metabolite, causing genomic instability by attenuating the function of spindle-assembly checkpoint, can serve as a biomarker for breast cancer. American journal of translational research, 11(8), 4992.
  2. Samavat, H., & Kurzer, M. S. (2015). Estrogen metabolism and breast cancer. Cancer letters, 356(2), 231-243.
  3. Baker, J. M., Al-Nakkash, L., & Herbst-Kralovetz, M. M. (2017). Estrogen–gut microbiome axis: physiological and clinical implications. Maturitas, 103, 45-53.
  4. Aubertin-Leheudre M, Gorbach S, Woods M, Dwyer JT, Goldin B, Adlercreutz H. Fat/fiber intakes and sex hormones in healthy premenopausal women in the USA. J Steroid Biochem Mol Biol 2008;112: 32–9.
  5. Recommended Daily Fibre Intake. (2019, April 08). Retrieved June 30, 2020, from https://cdhf.ca/health-lifestyle/recommended-daily-fibre-intake/
  6. Quagliani, D., & Felt-Gunderson, P. (2017). Closing America’s fiber intake gap: communication strategies from a food and fiber summit. American journal of lifestyle medicine, 11(1), 80-85.
  7. Muti P, Trevisan M, Micheli A, et al. Alcohol consumption and total estradiol in premenopausal women. Cancer Epidemiol.Biomarkers Prev. 1998; 7:189–193. [PubMed: 9521430]
  8. Noth, R. H., & WaIter Jr, R. M. (1984). The effects of alcohol on the endocrine system. Medical Clinics of North America, 68(1), 133-146.
  9. Yilmaz, B., Terekeci, H., Sandal, S., & Kelestimur, F. (2019). Endocrine disrupting chemicals: Exposure, effects on human health, mechanism of action, models for testing and strategies for prevention. Reviews in Endocrine and Metabolic Disorders, 1-21.
  10. Crinnion, W. J., & Pizzorno, J. E. (2018). Clinical Environmental Medicine-E-BOOK: Identification and Natural Treatment of Diseases Caused by Common Pollutants. Elsevier Health Sciences.
  11. Siiteri, P. K. (1987). Adipose tissue as a source of hormones. The American journal of clinical nutrition, 45(1), 277-282.
  12. Berga, S. L. (2019). Stress-induced anovulation. In Stress: Physiology, Biochemistry, and Pathology (pp. 213-226). Academic Press.
  13. Datta, M., Roy, P., Banerjee, J., & Bhattacharya, S. (1998). Thyroid hormone stimulates progesterone release from human luteal cells by generating a proteinaceous factor. Journal of endocrinology, 158(3), 319-325


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Dr. Sarah Nyrose, ND

Dr. Sarah Nyrose is a naturopathic doctor practicing in Victoria, BC. She has a clinical focus on hormone and metabolic health. Sarah takes a functional medicine approach when investigating the underlying cause of symptoms and when devising personalized treatment plans. Outside of the clinic, she is a co-founder of Fare & Flourish (fareandflourish.com), a blog focused on food as medicine. You can find out more about her practice at drsarahnyrose.com