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If you have PCOS, there’s a chance you’ve heard the term “oestrogen dominance”—but what does it actually mean, and why does it matter for your health?

Despite how common hormonal imbalances are, oestrogen dominance remains poorly understood in mainstream medicine. Yet it’s a crucial piece of the PCOS puzzle that deserves your attention.

Understanding Female Sex Hormones

Hormones are chemical messengers produced by your endocrine glands, and your health depends on the delicate balance of more than 50 different hormones circulating in your body.

The key female sex hormones include:

Oestrogen – Actually a family of three different hormones:

• Oestradiol: The strongest form, produced primarily by your ovaries
• Oestrone: A weaker form, the primary type found after menopause
• Oestriol: The weakest form, a breakdown product of oestradiol

Progesterone – Produced mainly by the corpus luteum (the gland formed after ovulation), as well as the placenta during pregnancy and the adrenal glands

Testosterone – Yes, women produce this too! In fact, testosterone is necessary for producing oestrogen through an enzyme called aromatase. But in PCOS, testosterone levels are often elevated—it’s actually part of the diagnostic criteria.

These hormones naturally fluctuate throughout the menstrual cycle. But sometimes these changes become too drastic, leading to complications like oestrogen dominance.

What Is Oestrogen Dominance?

Here’s what surprises most women: Oestrogen dominance doesn’t always mean you have too much oestrogen.

It means you have too much oestrogen relative to progesterone, or your body isn’t breaking down and eliminating oestrogen efficiently.

The term was coined by Dr. John R. Lee in his groundbreaking book What Your Doctor May Not Tell You About Menopause. He explained how progesterone levels influence oestrogen concentration, and how progesterone depletion can lead to oestrogen dominance—even when oestrogen levels appear “normal” on blood tests.

So oestrogen dominance can occur when:

• Oestrogen levels are too high
• Progesterone levels are too low
• Both hormones appear “normal” in testing, but the ratio between them is off
• Your body struggles to metabolise and eliminate oestrogen properly

Why Does Oestrogen Dominance Happen in PCOS?

Several factors contribute to oestrogen dominance, and many are particularly relevant for women with PCOS:

1. Polycystic Ovary Syndrome Itself

PCOS is one of the most common causes of oestrogen dominance. Here’s why:

Lack of ovulation means the corpus luteum doesn’t form, so progesterone production plummets. Without adequate progesterone to balance oestrogen, dominance occurs—even if oestrogen levels aren’t particularly high.

Insulin resistance (present in approximately 70% of women with PCOS) increases the enzyme aromatase, which converts testosterone to oestrogen, raising oestrogen levels.

In fact, PCOS is the most frequent cause of anovulatory infertility, and it tends to go hand in hand with oestrogen dominance.

2. Excess Body Fat

Fat tissue isn’t just passive storage—it’s metabolically active and produces oestrogen. The more body fat you carry, the more oestrogen your body produces. Since excess weight is typical in PCOS, this creates a vicious cycle.

3. Chronic Stress

Stress hijacks your hormone production. When your body is in “fight or flight” mode, it prioritises making stress hormones (cortisol) over sex hormones like progesterone. This shift worsens the oestrogen-to-progesterone ratio.

4. Poor Liver Detoxification

Your liver is responsible for breaking down used oestrogen so it can be eliminated from your body. When liver function is compromised (by alcohol, poor diet, toxins, or chronic inflammation), oestrogen gets recycled instead of removed.

5. Gut Dysfunction

Your gut plays a crucial role in eliminating oestrogen. When you have gut dysbiosis (imbalanced gut bacteria) or constipation, an enzyme called beta-glucuronidase can “unlock” oestrogen that was packaged for elimination, allowing it to be reabsorbed into your bloodstream.

6. Environmental Oestrogens (Xenoestrogens)

We’re exposed daily to synthetic chemicals that mimic oestrogen in the body, including:

• BPA and BPS in plastics, food containers, and receipt paper
• Parabens and phthalates in personal care products
• Pesticides on conventional produce
• Hormones in conventional meat and dairy

These xenoestrogens accumulate in your body and add to your total oestrogen burden.

7. Hormonal Medications

Birth control pills and hormone replacement therapy can contribute to oestrogen dominance, particularly formulations high in synthetic oestrogens.

8. Autoimmune Conditions

In some autoimmune diseases, oestrogen enhances autoimmunity, creating a feedback loop. This may explain why women are more likely to develop autoimmune conditions, and why these conditions often coexist with PCOS.

How Oestrogen Dominance Shows Up

The symptoms of oestrogen dominance can vary in intensity from person to person, but common signs include:

• Heavy, irregular, or painful periods
• Severe PMS symptoms
• Bloating and fluid retention
• Fibrocystic or tender breasts
• Weight gain, especially around the hips and thighs
• Stubborn belly fat
• Fatigue and low energy
• Sleep disturbances
• Mood swings, anxiety, and irritability
• Brain fog and memory problems
• Hair loss or thinning
• Acne (particularly jawline and chin)
• Low sex drive
• Fertility problems
• Cold hands and feet
• Sugar cravings
• Thyroid dysfunction
• Slowed metabolism

Interesting fact: Research shows that high oestrogen combined with low progesterone is associated with increased assertiveness in women—not always a bad thing!

Why This Matters: The Long-Term Risks

When left unmanaged, oestrogen dominance doesn’t just cause uncomfortable symptoms—it can increase your risk of serious health conditions:

• Breast cancer – Excess oestrogen, particularly specific metabolites, increases breast cancer risk
• Endometrial cancer – Unopposed oestrogen can cause abnormal cell growth in the uterine lining
• Thyroid problems – Excess oestrogen can block thyroid hormone receptors
• Heart disease – Hormonal imbalance affects cardiovascular health
• Type 2 diabetes – The metabolic dysfunction in PCOS, worsened by oestrogen dominance, significantly increases diabetes risk

Getting Tested

If you suspect oestrogen dominance, work with a healthcare professional who understands hormonal health—such as an integrative doctor, naturopath, or functional medicine practitioner.

Testing options include:

Blood tests measuring:

• Oestradiol (normal: 15-350 pg/mL in premenopausal women)
• Oestrone (normal: 17-200 pg/mL in premenopausal women)
• Progesterone (varies by cycle phase)
• The oestrogen-to-progesterone ratio

Saliva testing can assess hormone levels throughout your cycle

DUTCH test (Dried Urine Test for Comprehensive Hormones) shows not just hormone levels but also how your body is metabolising them—crucial information for oestrogen dominance

Managing Oestrogen Dominance: Your Action Plan

The good news? There are several steps you can take to restore hormonal balance and prevent complications.

1. Optimise Your Diet

Increase Fibre Intake
Fibre helps your digestive tract eliminate oestrogen. Aim for 30-35 grams daily from vegetables, fruits, legumes, nuts, and seeds.

Eat Cruciferous Vegetables
Broccoli, cauliflower, cabbage, Brussels sprouts, and kale contain compounds that support healthy oestrogen metabolism. Aim for 1-2 servings daily.

Consider Phytoestrogens Carefully
Plant compounds in soy, flaxseeds, and legumes act as weak oestrogens. They can block more potent oestrogens from binding to receptors, potentially reducing your active oestrogen load. The research is nuanced—some people benefit, others don’t. Pay attention to how your body responds.

Include Quality Protein
Eat lean fish, grass-fed meat, organic chicken, free-range eggs, and plant proteins at each meal to support hormone production and liver detoxification.

Get Healthy Fats
Omega-3 fatty acids from fish, nuts, seeds, avocado, and olive oil are essential building blocks for hormones.

Eliminate Inflammatory Foods
Remove or significantly reduce sugar, processed foods, excess caffeine, and alcohol—all of which disrupt hormone balance and liver function.

2. Support liver detoxification

Your liver is the primary place where your body breaks down sex hormones (like oestrogen, progesterone, and testosterone) to get them ready to be removed.

Support it by:

• Drinking 2+ litres of filtered water daily
• Limiting or avoiding alcohol
• Eating anti-inflammatory foods rich in antioxidants
• Including bitter foods like dandelion greens, arugula, and radicchio
• Considering supplements like milk thistle, N-acetylcysteine (NAC), or B vitamins (consult your practitioner)

3. Heal your gut

Optimise digestion and elimination to prevent oestrogen reabsorption:

• Eat probiotic-rich foods (fermented vegetables, kefir, A2 yoghurt)
• Include prebiotic fibres (onions, garlic, asparagus, Jerusalem artichokes)
• Address constipation—you should ideally have at least one bowel movement daily
• Consider a high-quality probiotic supplement
• Identify and address food sensitivities

For a comprehensive approach, check out my article: The 16 Point Checklist For A Better PCOS Gut.

4. Move your body

Regular exercise:

• Helps maintain a healthy weight, reducing fat tissue’s oestrogen production
• Improves insulin sensitivity
• Reduces stress and cortisol levels
• Directly lowers oestrogen levels (studies show it can reduce breast cancer risk in high-risk women)

Aim for at least 30 minutes of moderate activity most days, combining strength training with cardiovascular exercise.

5. Manage stress effectively

Chronic stress leads to insulin resistance and worsening hormone imbalance. Implement daily stress-management practices:

• Meditation or mindfulness
• Deep breathing exercises
• Yoga or tai chi
• Time in nature
• Adequate rest and relaxation
• Setting boundaries

6. Prioritise sleep

Sleep is essential for liver function and detoxification. Aim for 7-8 hours of quality sleep nightly by:

• Maintaining a consistent sleep schedule
• Creating a dark, calm bedroom environment
• Avoiding screens 1-2 hours before bed
• Managing blood sugar to prevent nighttime waking

7. Reduce xenoestrogen exposure

Minimise your exposure to synthetic oestrogens:

In the kitchen:

• Use glass, stainless steel, or ceramic containers instead of plastic
• Never microwave food in plastic
• Avoid canned foods (most cans are lined with BPA)
• Choose organic produce when possible, especially for the “Dirty Dozen”
• Select organic, grass-fed, or pasture-raised animal products if you choose to eat meat

Personal care:

• Read labels and avoid products containing parabens, phthalates, and synthetic fragrances
• Choose natural, organic cosmetics and skincare
• Use natural cleaning products

Daily habits:

• Decline receipts or request email versions (thermal paper contains BPA)
• Filter your drinking water
• Vacuum and dust regularly to reduce exposure to flame retardants

8. Consider targeted supplements

Work with a qualified practitioner to determine which supplements might benefit you:

Indole-3-Carbinol (I3C) or DIM
Concentrated cruciferous vegetable compounds that support healthy oestrogen metabolism, shifting it toward beneficial metabolites.

Broccoli Sprout Extract
Contains glucosinolates and sulforaphane—potent compounds that activate your body’s detoxification systems.

Curcumin
The active compound in turmeric provides anti-inflammatory and antioxidant benefits, while also supporting liver detoxification.

Calcium-D-Glucarate
Prevents the enzyme beta-glucuronidase from reactivating oestrogen in the gut, ensuring it’s eliminated rather than reabsorbed.

Vitex (Chasteberry)
May help increase progesterone production, particularly beneficial if you’re not ovulating regularly.

B Vitamins
Essential for liver detoxification pathways that process oestrogen.

Magnesium
Supports stress management, sleep quality, and hundreds of enzymatic reactions, including hormone metabolism.

The Bottom Line

Oestrogen dominance is a serious but manageable condition that significantly affects quality of life—and when left unaddressed, can increase the risk of serious diseases.

Too many women and ovarian owners accept hormonal chaos as a “normal” part of their lives. It’s not.

The causes of oestrogen dominance are numerous, but so are your options for managing it. With a proactive attitude and the right approaches—combining nutrition, lifestyle changes, stress management, and targeted supplemental support—you can restore the balance between oestrogen and progesterone.

You don’t have to live at the mercy of a hormonal imbalance. You have more control than you think.

From PCOS to perfect health, with love,

Dr. Rebecca Harwin
The PCOS Expert
Chiropractor & Bestselling Author of
Conquer Your PCOS Naturally
www.ConquerYourPCOSNaturally.com

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