What is oestrogen dominance?

oestrogen dominance

Oestrogen dominance is a commonly used term but what is it and what does it mean?

Let’s start by looking at what oestrogen is and what it does.

Oestrogen is made in the ovaries, fat cells and adrenal glands and oestrogen receptors are in every single part of the body including brain, bowel, thyroid, and muscle. At puberty it plays a role in the development of the secondary sex characteristics (breast growth, menstrual cycle, and body hair development). It is also responsible for thickening the endometrial lining and regulating the menstrual cycle.  

It is an “excitor” hormone and stimulates the body. 

Oestrogen is an umbrella term for three different hormones: 

Estradiol – the predominant fertility hormone.  

Estriol – the pregnancy version of oestrogen. 

Estrone – The hormone present post menopause after estradiol stops being made. 

Oestrogen is used by the body and then broken down by the liver and excreted out. It is important to note that peri-menopausal women can have oestrogen levels 20%-30% higher compared to women of reproductive age before peri-menopause due to the fluctuations in hormones at this time. 

Oestrogen plays many vital roles in the body when there is the correct amount it: 

  • Regulates body fat.
  • Promotes female reproduction function.
  • Promotes heart health.
  • Promotes bone formation and cell health.
  • Regulates blood sugars.

Not enough oestrogen in post menopause can cause the following symptoms: 

  • Mood swings
  • Weight gain or loss
  • Memory loss
  • Menstrual cycle issues
  • Vaginal dryness
  • Irritability
  • Fatigue
  • Hot flushes
  • Insomnia 
  • Stress and anxiety
  • Loss of bone density 
  • Reduced muscle mass 
  • Increased potential for strokes and heart attacks

There are two other types of oestrogen that have a profound effect on women’s bodies: 

Phyto oestrogens  

These are plant chemicals that have a similar effect on our body as oestrogen. These can be very beneficial in supporting women through the latter stages of menopause, but they can wreak havoc earlier in life if we are exposed to them a lot and can mess up our natural hormone signaling.  

Xeno oestrogens (pronounced zeeno-oestrogen)  

Xeno oestrogens are compounds that mimic oestrogen, and they commonly contribute to health issues. Xeno means “foreign”. They are also referred to as endocrine disrupting chemicals (EDCs). 

They are fake oestrogens brought about by pollution, toxicity, poor diet, and an imbalanced gut microbiome. A buildup of xeno oestrogens can disturb our natural oestrogen levels and cause a buildup which the body struggles to process. Historic high exposure to xeno oestrogens can be a reason why women feel so awful during peri menopause and can be a major contributing factor as to why women aren’t able to tolerate or process HRT. They are also a contributor to many hormone issues earlier in life.  

Xeno-oestrogens are therefore a major contributor to having too much oestrogen, but having too much oestrogen is common.  

Oestrogen Dominance  

Oestrogen dominance causes huge issues in the body. We do commonly see a pattern of symptoms suggesting women are oestrogen dominant throughout their whole lives.  

Oestrogen dominance symptoms include a variety of conditions women can have experienced historically but are also common during perimenopause these include: 

  • heavy periods or period issues
  • breast pain
  • fibroids
  • premenstrual irritability
  • weight gain
  • Thyroid suppression
  • Gut dysbiosis and digestive issues 
  • Immune function impairment including histamine issues and allergies. 
  • Premenstrual syndrome and Premenstrual dysphoric disorder (PMDD)
  • Poly cystic ovary syndrome (PCOS)
  • Endometriosis 
  • Adenomyosis
  • Hormone sensitive cancers

When in balance oestrogen helps optimise the action of insulin. However, when there is too much oestrogen this action is affected, and if we have too much insulin this action is also affected, and we are more susceptible to insulin resistance. Equally when post-menopausal, oestrogen is lower, and we have an increased susceptibility to insulin resistance. This is one of the reasons for weight gain in peri menopause. The connection between insulin and oestrogen doesn’t just happen in women it also happens in men, and we see in obesity that men are developing the sex characteristics of women such as enlarged breast and hips. We are therefore seeing the interaction between insulin and oestrogen become one of the major health issues in the world.  

Causes of oestrogen dominance 

Many things trigger oestrogen dominance such as hormonal birth control, impaired gut function, perimenopause, hyperinsulinemia, stress, xeno-oestrogen, and endocrine disruptor chemical exposure, HPA axis dysregulation. This list shows how women could have been dealing with oestrogen dominance for many years.  

Oestrogen dominance however can also occur when oestrogen levels are optimal, but we have less than optimal levels of progesterone. This is something that happens in perimenopause but we are seeing it in younger and younger girls, often in their early teens.  


Primarily progesterone helps prepare the female body for conception and pregnancy whilst regulating the menstrual cycle. It is made from a hormone called pregnenolone (this will become important later) 

Progesterone is a startlingly beneficial hormone; it is produced in large quantities by the ovaries during ovulation. It helps prepare the lining of the uterus to receive the egg if a sperm fertilizes it. It also acts on the breasts, brain, immune system, and detoxification system. It is also a calming hormone as opposed to oestrogen which is an exciter hormone.  

Some of the benefits of progesterone include: 

Boosts energy by stimulating the thyroid and heating up metabolism. Which is why body temperature goes up half a degree when progesterone is made after ovulation. It also stabilises communication between the hypothalamus and adrenal glands and so relieves HPA dysregulation that we explored in the previous chapter.  

Calms us down Progesterone is a natural calming hormone.  

Soothes mood and rescues sleep (remember this when we look at what happens to hormones during menopause later on in this chapter) 

Nourishes hair and clears skin.   

Lightens periods by counteracting oestrogen’s stimulating effect on the uterine lining. 

Prevents autoimmune disease because it modulates immune function, reduces inflammation, and up-regulates detoxification enzymes. 

Builds bones and muscle by stimulating http://www.cemcor.ubc.ca/sites/default/files/uploads/5_Ovulation_and_Bone_Health.pdf bone building cells and the growth of new muscle. 

Protects against some cancers by counteracting oestrogen’s stimulating effect on breast and uterine tissue. 

Insulin regulation It controls and stabilises the production of insulin in the pancreas, which given the worldwide issue of insulin resistance is a very important job.  

Conditions associated with progesterone deficiency: 


heavy periods 



hair loss 


autoimmune disease  




Lack of concentration 

“wired but tired” 



Excess insulin production 

premenstrual syndrome (PMS) 

premenstrual migraines 





primary ovarian failure 



Irregular periods 

Palpitations with no cause found in the heart 

Short luteal phase, (the time between ovulation and your period. 
It should be at least 11 days. 

Low temperatures in the luteal phase. 

Premenstrual spotting. 


Progesterone is vital to women’s physical and mental health because of its calming action, and it is this fact that is often overlooked by the medical model which focuses more on oestrogen levels. In fact, in many circles, progesterone has been wrongly reduced to just being important for pregnancy. Its effects on digestion, emotions, the nervous system, mood, weight stabilisation and sleep are often sidelined.  

When we look at the history of women’s healthcare in the developed nations it is fascinating to view many of the conditions that women have been labelled with such as ‘hysteria’ through the lens of a lack of progesterone. It becomes incredibly frustrating when you realise that many conditions such as PMDD have such links to low progesterone but haven’t been treated with progesterone.  

So, is It oestrogen dominance or progesterone deficiency?

That is the million-dollar question and one that doesn’t come with an easy answer because of the medical model’s blind spot around progesterone. Even in young women experiencing menstrual cycle issues there is a reticence to test for progesterone levels and it certainly isn’t tested for in peri menopause, so the answer is it could be one or both.

It is common in peri menopause to have both oestrogen dominance (due to recirculating xeno oestrogens and poor gut health) and low progesterone by nature of the fact of being in peri menopause.

It can be common in earlier life also if you’ve been on the pill or have a history of using lots of toiletries/cosmetics that contribute to our oestrogenic load or have a highly refined carbohydrate diet or eat a lot of food that you are intolerants to such as wheat or dairy.

But what do I do about it?

The simple answer is to work with a coach who is highly trained to explore your health history and who can work with you to find the right diet, rebalance your gut and reduce any oestrogen dominance using targeted nutraceutical supplements. They will also be able to discuss the different options available to you for working out which approach to HRT you’d be happy with. 

Can’t afford a coach? Try our free symptom assessor