Estrogen Dominance in PCOS

Jul 07, 2024
Estrogen Dominance in PCOS
PCOS often involves hormonal imbalances beyond high androgens and insulin. Estrogen dominance, a common issue, can occur when estrogen is high relative to progesterone. Symptoms include heavy periods and tender breasts.

Estrogen Dominance in PCOS

PCOS is a complex disorder with many moving parts. Often, women experience not just one but several hormonal imbalances related to PCOS. You might be familiar with high androgens (like testosterone) and high insulin in many PCOS cases, but what about estrogen? Is there a connection between PCOS and estrogen balance, and what can you do to promote more balance and well-being?

Let’s dive into this exciting topic that affects so many women. Keep reading to learn more about:

  • Hormonal imbalances in PCOS
  • PCOS and estrogen
  • Estrogen dominance – root causes and symptoms
  • How to balance estrogen in PCOS

PCOS Hormone Imbalances

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder affecting 5 to 15% (or up to 20%) of women of reproductive age. Endocrine (hormonal) changes affect ovulation, fertility, and metabolic health. PCOS is a risk factor for cardiometabolic diseases, gestational diabetes, and pregnancy complications.

A provider diagnoses PCOS when a woman meets two of the three Rotterdam criteria:

  1. Hyperandrogenism (high androgens based on lab tests or symptoms)
  2. Irregular or anovulatory menstrual cycles
  3. Signs of polycystic ovaries on ultrasound

Elevated androgens (like DHEA and testosterone) are part of the diagnostic criteria, affecting 60 to 80% of women with PCOS. This hormonal imbalance causes symptoms such as male-pattern hair growth and acne. However, it’s not the only hormonal change we see in PCOS.

Many women also experience insulin resistance since elevated androgens drive insulin, and vice versa. Insulin is the hormone that helps move sugar (from carbohydrate foods) into the cells for energy. With insulin resistance, this mechanism doesn’t work as well, leading to elevated blood sugar and insulin levels and impairing ovulation. 

Please read PCOS and Androgen Excess to learn more about these hormonal patterns. Next, we’ll discuss estrogen imbalances common in women with PCOS.

PCOS and Estrogen Dominance

Estrogen is a group of sex hormones essential for reproduction and total body wellness. A primary role of estrogen is to proliferate (grow) the endometrium (uterine lining) in the first half of the menstrual cycle (the follicular phase). As estrogen rises, the tissue makes more estrogen receptors, and the uterine lining grows. Estrogen also promotes progesterone receptors, and after ovulation, progesterone binds to inhibit estrogen’s effects and control the growth. In this way, progesterone helps balance out estrogen and control conditions within the uterus.

(Please read this article to review a healthy menstrual cycle).

In PCOS, estrogen receptors and the balance between estrogen and progesterone become abnormal, resulting in estrogen dominance. Even though estrogen imbalance isn’t a part of the diagnostic criteria, we see it a lot clinically.

Estrogen dominance refers to high estrogen relative to progesterone. It can occur when estrogen levels are normal, but progesterone is low. Or when estrogen is high, and progesterone is normal or low. In either case, there isn’t enough progesterone to keep estrogen in check.

Symptoms of estrogen dominance or high estrogen include:

  • Heavy periods
  • Painful periods
  • Sore, tender breasts
  • Water retention
  • Headaches and migraines
  • Irritability
  • Premenstrual syndrome (PMS)
  • Cravings
  • Weight gain
  • Fertility challenges

There are several reasons estrogen dominance occurs with PCOS. The reasons include:

  • Anovulatory cycles – Ovulation must occur for progesterone production. In PCOS, if you aren’t ovulating consistently or regularly, progesterone will be low. Low progesterone contributes to estrogen dominance symptoms, whether estrogen levels are high or normal.


  • Aromatization – Aromatization is the process by which testosterone converts to estrogen. In PCOS, the ovaries tend to produce more testosterone than estrogen. Still, high testosterone can convert to estrogen, especially in fat tissue. Women with PCOS can have high testosterone and high estrogen. (Fun fact: All estrogen starts as testosterone).


  • Sex hormone binding globulin (SHBG) – SHBG is a transport protein that carries hormones, mostly estrogen and testosterone. When hormones are bound to SHBG they are inactive and not available for use. Women with PCOS may have lower SHBG. When SHBG is low, it means there is more free estrogen and testosterone circulating. This mechanism can contribute to estrogen dominance.


With many factors driving estrogen, it’s no wonder that estrogen dominance symptoms affect so many women with PCOS.

How to Support Healthy Estrogen Balance

With several hormones out of balance in PCOS, it can be hard to know where to start with PCOS. That’s why working with your trusted TārāMD provider for testing and guidance is essential. Each woman with PCOS can have a different hormonal pattern and root causes, requiring a personalized treatment strategy.

Luckily, the health habits you develop to balance insulin and testosterone, like prioritizing a nutritious whole-food diet and dialing in exercise, will support all hormonal systems, including estrogen.

Don’t skip anti-inflammatory nutrition, movement, sleep, and stress management; these pieces will provide a solid foundation for more advanced interventions and protocols. You can also rely on them for health and longevity as you enter perimenopause and the later decades of life.

With the foundations in place, here are some other strategies to discuss with your provider for estrogen dominance:


  • Support estrogen detoxification and clearance – The liver detoxifies estrogen in a two-step process, and then metabolites are removed from the body via the colon. First, ensure regular daily bowel movements and support a healthy gut microbiome to prevent estrogens from being reabsorbed into the body. Then, ensure optimal liver detoxification. We often recommend a DUTCH hormone test to assess estrogen levels and metabolites. Your TārāMD team will help you with the specifics of treatment, and you can likely consider dietary changes like increasing cruciferous vegetables and supplements like DIM, sulforaphane, resveratrol, glutathione, and NAC.


  • Increase phytoestrogens – Phytoestrogens are plant estrogens weaker than human estrogens. In cases of estrogen dominance, phytoestrogens can bind to estrogen receptors, displacing estrogen and causing a lower estrogenic response. You can find phytoestrogens in foods like flaxseeds and whole organic soy (edamame, tofu, and tempeh). Phytoestrogenic supplements may also be supportive. Learn more here.


  • Progesterone therapy – Bioidentical progesterone can help balance the symptoms of estrogen dominance in women with androgenic PCOS. Progesterone is a prescription therapy used during the luteal phase (the second half of the menstrual cycle). Please note that bioidentical progesterone is different from progestins in oral contraceptives that are often prescribed for PCOS. We can help you understand the pros and cons of various medical interventions. Please read more about bioidentical hormone replacement therapy here.


  • Clean up your environment – Understand what chemicals act like estrogen and avoid them as much as possible by reducing exposure. Endocrine disruptors are lurking all around, and you can decrease them by:
    • Limiting or avoiding plastic use, especially with food and beverages
    • Choosing fresh vs. canned
    • Buying organic as much as possible
    • Choosing non-toxic detergents and cleaning products
    • Avoiding flame retardants in clothing and furniture
    • Choosing safe skincare and personal care products

For more resources and action steps, please read Endocrine Disruptors – Hidden Causes of Hormonal Imbalance.


PCOS is complex, and a lot is happening under the surface contributing to various hormone imbalances. Testosterone and insulin are hormones often at the top of the PCOS conversation, but changes in estrogen are also critical to evaluate and understand.

The good news is that you don’t have to figure it all out on your own! At TārāMD, we will comprehensively examine your symptoms, hormones, and metabolic health to develop an individual approach that helps you reach your health goals, reduce symptoms, and maintain fertility for as long as possible.


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