Over the years of working with people with Hashimoto’s, it has become clear to me that there is a strong relationship between sex hormones and thyroid hormones. One client’s story comes to mind as one that will resonate with many of you. At the time, this client had just turned 40 and started to see some changes in her previously very regular cycle, including mid-cycle spotting and a heavier flow. She complained of premenstrual symptoms such as tender breasts, irritability, and fatigue that seemed to last, in her words, “all month long.”
She also had Hashimoto’s and had addressed (or had begun to address) several of her root causes by implementing an anti-inflammatory, grain-free diet, balancing her blood sugar, and working to heal a leaky gut. Yet, these hormonal symptoms were new.
Her gynecologist suggested that, since she might be having hormonal fluctuations related to perimenopause, she should start taking birth control to help regulate her cycle. This felt like a band-aid approach to my client, as she was interested in digging deeper for her root cause.
By working with her functional practitioner who did some detailed hormonal testing, she learned that her symptoms were due to estrogen dominance. She had trouble clearing estrogen from her body, due to an impaired detoxification pathway. By using key nutrients and herbs for liver support, along with implementing some dietary and lifestyle changes, she was able to reverse her symptoms.
I share this story with you as one example of how estrogen dominance plays out in real life.
What is Estrogen Dominance?
There are two scenarios in which estrogen dominance can occur:
- When there is excess estradiol (one type of estrogen) and too little progesterone.
- When estrogen is broken into too many antagonistic metabolites (symptom-causing substances formed by metabolism).
Let’s take a look at the first scenario.
Estrogen and progesterone work together in the body, along with the adrenal and thyroid hormones, to keep us feeling our best. Estrogen and progesterone work in rhythm together to create the female cycle.
There are three major, naturally-occurring forms of estrogen, called estrone (E1), estradiol (E2), and estriol (E3). The fourth type, estetrol (E4), is only produced during pregnancy.
Estrone is produced in the ovaries and decreases significantly during pregnancy and after menopause. Of all the estrogens, it has the weakest effect on the body, but does help maintain bone health.
Estradiol is also produced in the ovaries and is the most prevalent form of estrogen. It is responsible for the development of female sex characteristics, and prepares the reproductive cycle for pregnancy.
Estriol is the main estrogen in the body during pregnancy, and is made by the placenta. It plays a large role in fetal development. Small amounts of estriol are present in perimenopause.
During the female reproductive cycle, estrogen (estradiol) stimulates the uterine lining to thicken in preparation for ovulation. This estrogen release also boosts mood, protects bones, supports metabolism, and more. This first half of the cycle is called the Follicular Phase, because follicle-stimulating hormone (FSH) stimulates the ovaries to produce estrogen, and pushes the body toward ovulation.
After a rise in luteinizing hormone (LH), an egg is released in ovulation, and the hormone progesterone takes over. This is called the Luteal Phase. Progesterone is responsible for maintaining the uterine lining and maintaining a pregnancy if that egg becomes fertilized. If the egg is not fertilized, progesterone will continue to drop until menstruation occurs and the cycle starts all over. Progesterone also reduces inflammation and calms the nervous system. In addition, it helps to stimulate thyroid hormone, which we will talk about more in a little while.
Estrogen dominance is a state in which estrogen and progesterone are out of balance. There are two situations of estrogen dominance. The first situation is the most common, where estrogen levels are very high. This excess estrogen occurs because the body is making too much, it’s coming from an external source, or it’s recirculating because the body isn’t sufficiently detoxifying estrogen.
In the second situation of estrogen dominance, estrogen levels may be high or even normal, but progesterone is low, so the ratio of estrogen to progesterone is high. Estrogen dominance can be more common after a pregnancy or in menopause, because of the rapid decrease in progesterone production.
Let’s explore how estrogen dominance happens in the second scenario. Estrogen gets broken up into several metabolites; some are protective and beneficial, while others are antagonistic and therefore symptom-causing:
- 2-hydroxyestrone (2-OH): A “good” estrogen that does not stimulate cell growth and can block the action of stronger, potentially cancer-causing estrogens.
- 4-hydroxyestrone (4-OH): These are potentially harmful, with increased estrogenic activity that can worsen symptoms.
- 16-alpha-hydroxyestrone (16-OH): These are potentially harmful and are associated with an increased risk of breast cancer.
The metabolism of these estrogens is largely dependent on the health and efficiency of your liver and the digestive tract, though genetics do play a role as well.
Both of these estrogen dominance scenarios (estrogen-to-progesterone ratio, and estrogen metabolite ratio) can cause a host of symptoms, which include:
- PMS and PMDD
- Ovarian cysts
- Uterine polyps
- Breast lumps
- Breast cancer
- Thyroid nodules
- Thyroid cancer
- Elevated anti-thyroglobulin antibodies
- Ovarian cancer
- Water retention
- Brown spots or discoloration on upper lip or side of the face
- Mood swings
- Tender breasts
- Irregular periods
- Heavy periods
- Hair loss
- Thyroid dysfunction mimicking hypothyroidism
- Stubborn hip/butt fat and cellulite
- Brain fog
- Insulin resistance
- Lowered libido (sex drive)
When something is so common and pervasive in our lives, we assume that it’s normal. For example, so many women experience lumpy boobs, fibroids, PMS, and abnormal periods (and that’s just the tip of the iceberg) that we start to think these are “normal” things we have to deal with as women. The truth is, they are not normal and can be addressed when we get to the root cause of what is causing these imbalances.
Estrogen Dominance & Hashimoto’s
If you’ve read my book, Hashimoto’s: The Root Cause, you will likely know by now that hormone imbalances can contribute to Hashimoto’s. This can partially explain why pregnancy can trigger Hashimoto’s, and why Hashimoto’s is more common in women. It makes sense to me because of how all of the hormone systems in the body are connected, and thyroid hormone doesn’t operate in isolation.
In 2015, I came across a study of women with polycystic ovarian syndrome (PCOS), some of whom also had Hashimoto’s. PCOS is characterized by insulin resistance or adrenal imbalance, elevated testosterone, and cysts on the ovaries. Scientists wanted to figure out why some women with PCOS got Hashimoto’s and why some didn’t, and ran hormonal tests on all of the women involved in the study.
Lo and behold, they determined that excess estrogen – also known as estrogen dominance – can trigger Hashimoto’s. The study showed more Hashimoto’s thyroiditis, elevated thyroid stimulating hormone (TSH) and elevated thyroid antibodies in the study participants with higher estrogen levels. This was not surprising to me, as excess estrogen has also been linked to thyroid cancer.
Here is the connection. Remember how estrogen and progesterone work as opposites and provide balance? Well, estrogen suppresses thyroid hormone and increases our need for TSH, while progesterone stimulates thyroid hormone. Thus, excess estrogen levels and low progesterone levels can cause hypothyroidism.
In a 2013 randomized controlled trial of women with hot flashes, those who took a progesterone medication saw an increase in thyroid hormone levels.
Beyond the estrogen-thyroid connection, there is an immune connection as well. In hypothyroidism, it is challenging for the body to detoxify estrogen, due to impaired liver function. Prolonged exposure to excessive estrogen can lead to an increase in anti-TPO antibodies and anti-TG antibodies, and the development of autoimmune thyroid conditions.
Most cases of Hashimoto’s thyroiditis are diagnosed in women; however, similar mechanisms seem to play a role in men. One study found that increased circulation of estrogen in men was also related to thyroid autoimmunity.
Estrogen has been found to perpetuate inflammatory and autoimmune disease, while progesterone deficiency and estrogen fluctuations can worsen the autoimmune attack. The reason for this may be the effect of hormones on the immune system.
Th1 is the branch of the immune system that is characterized by inflammation. Here, the immune system “attacks” cells that it identifies as foreign or “non-self” cells. Estrogen appears to enhance this Th1 response, and low progesterone appears to do the same. This may be another connection to the development of Hashimoto’s during menopause or after pregnancy, where there is a drop in progesterone and a rise in the Th1 branch of the immune system, which can lead to self antigens that cause autoimmune disease.
I want to mention one more connection between Hashimoto’s and estrogen that has to do with fertility. It is well known that Hashimoto’s and hypothyroidism increase the risk for miscarriage, because thyroid hormone is so important for a healthy pregnancy. However, oftentimes, thyroid health is one of the last things to be investigated when a couple is struggling with infertility.
Furthermore, the hormonal therapies that accompany procedures like IVF (in vitro fertilization, a procedure where the sperm fertilizes the egg outside of the body and is then implanted in a woman’s uterus) actually increase circulating estrogen and can further suppress thyroid function.
Causes of Estrogen Dominance
The science relating estrogen dominance to hypothyroidism and Hashimoto’s is pretty compelling, but what causes estrogen dominance? Let’s go deeper to uncover the root causes. Remember, there is the case of excess estrogen and also the case of low progesterone, which affects the estrogen-progesterone ratio.
Here are some causes of excess estrogen:
- Hormonal birth control. The hormones in birth control pills suppress our own body’s production of estrogen and progesterone through a negative feedback loop mechanism. Birth control pills flood our bodies with high doses of artificial estrogen and progesterone, causing our production of natural hormones to turn off, preventing ovulation, and thinning the uterine lining. This can lead to a hormonal imbalance, such as estrogen dominance.
- Conventional Hormone Replacement Therapy (HRT). The synthetic hormones often prescribed in perimenopause and menopause for uncomfortable symptoms, can lead to estrogen dominance in much the same way as hormonal birth control. Interestingly, the synthetic progesterone, progestin, acts more like testosterone in the body.
- Xenoestrogens. We are not only exposed to estrogen from our internal hormone production, but also through non-organic foods, plastics, the water supply, and personal care products. Certain chemicals, called xenoestrogens, can mimic estrogen in the body. It’s possible that exposure to these chemicals may increase TSH and trigger the autoimmune process. Xenoestrogens include a variety of substances like soy, BPA, phthalates, and parabens.
- Obesity. Excess body fat can be a source of estrogen, as fat cells produce an excess of estrogen. What’s more, these same cells have the ability to convert testosterone into estrogen through an enzyme called aromatase. This is true for both men and women. It may be something to pay attention to for women in the menopausal years. As the ovaries decrease and then cease estrogen production, fat cells may try to take over. Reducing overall body fat can help reduce excess estrogen production.
- Poor detoxification. Estrogen is detoxified in the liver and then eliminated through the colon. Liver detoxification may be impaired in those with Hashimoto’s, as they often have nutrient deficiencies, impaired methylation (possibly caused by an MTHFR gene mutation that is common with autoimmunity), and other factors affecting liver function. If constipation is present, which can be related to hypothyroidism, estrogen may re-circulate through the body, making it challenging to lower estrogen levels.
- Constipation. This common occurrence in people with hypothyroidism can lead to estrogen dominance. When you are constipated, the metabolized hormones are not able to be efficiently eliminated, and re-enter the body. This inhibits the endocrine glands from producing more “fresh” hormones for the body to use, and lead to a buildup of estrogen in the body.
- Genetics. There are genes that can impact how well you metabolize estrogen in your body. One such gene, COMT, provides instructions for estrogen to be processed through a protective pathway. As a side note, when you are stressed, your body will make more epinephrine and norepinephrine, which makes it harder for the slow COMT enzyme to break down your sex hormones. A lot of women who struggle with estrogen dominance have the slow COMT enzyme.
If estrogen is high or normal, but progesterone is low, it is possible to still experience estrogen dominance. Here are some causes of low progesterone:
- Stress. Stress is often a main cause of low progesterone. When the body is under stress, making sex hormones for fertility falls low on its list of priorities. The body actually slows production of progesterone in favor of the production of the stress hormone, cortisol. This is true for short-term stress and also longer term stress that leads to HPA-axis dysfunction, or “adrenal fatigue”.
- Anovulatory cycles. An anovulatory cycle is one where menstruation occurs, but there wasn’t an egg released for ovulation, so there was no progesterone produced during the cycle. Anovulatory cycles can be a result of hormonal birth control and may be more common when coming off of birth control, after delivering a baby, and during the perimenopausal years. Additional causes of anovulatory cycles include low body weight, nutrient-deficient diets, and chronic stress.
Testing Estrogen Levels
The simplest way to look at estrogen and progesterone levels is through a blood test with your doctor. They can check for the three forms of estrogen (estrone or E1, estradiol or E2, and estriol or E3), along with progesterone.
If estrogen is high, or the estrogen to progesterone ratio is high, this would reveal a case of estrogen dominance. Normal estrogen levels for menstruating women range from 15 to 350 picograms per milliliter (pg/mL), while for postmenopausal woman, levels should be below 10 pg/mL.
Remember that testing while taking synthetic hormones won’t produce usable results, as the synthetic hormones suppress your natural hormones. It is also important to test during the Luteal Phase (second half) of your cycle.
There is a functional lab test that I love for looking at reproductive hormones, and it’s called the Dutch Complete from Precision Analytical. The Dutch Complete is a dried urine test that gives a much bigger picture of what is going on with hormone levels, including estrogen metabolism, testosterone, adrenal hormones, and other markers that can be useful for uncovering the root cause of your hormone imbalance. This test is also helpful for creating a personalized treatment plan with your practitioner.
While I am a big proponent of patient self-management and often recommend people self-order and interpret their own labs, I recommend working with a practitioner for interpretation of this particular test. This is because, while the test is easy to do, it’s a bit complicated to interpret — and hormones, when not used properly, can be dangerous.
Treatment: Conventional vs. Root Cause Approach
In the conventional medicine world, estrogen dominance isn’t fully recognized or evaluated routinely, even when a woman exhibits many of the symptoms outlined above. Part of this is likely because, as a society, we have falsely normalized elevated estrogen (or low progesterone) as a “normal” part of being a woman or of the aging process. More often than not, the conventional treatment is to mask the symptoms with the birth control pill or hormone replacement therapy, or be told that everything is normal and it is “all in your head.”
My Root Cause approach to estrogen dominance is more holistic. Instead of being symptom-focused, it is about digging deep and correcting the underlying imbalances. Often, a lot of this comes back to simple nutrition and lifestyle strategies.
Here are my top recommendations for addressing the root causes of estrogen dominance:
- Include brassica/cruciferous vegetables in your diet. Some examples include: broccoli, broccoli sprouts, turnips, cauliflower, cabbage, collard greens, and kale. These vegetables contain indole-3-carbinol and (I3C) and diindolylmethane (DIM), which are compounds that support estrogen metabolism and detoxification. Some individuals may say that these types of veggies should be avoided with Hashimoto’s and thyroid issues; however, this is a common thyroid myth.
- Include plenty of high-fiber produce as well. Dietary fiber supports the microbiome, which is important for estrogen metabolism and detoxification. It also helps to keep bowel movements regular so excess estrogen can leave the body. If fiber isn’t tolerated, address any root cause issues such as SIBO or leaky gut first.
- Choose high quality animal products in order to avoid exposure to growth hormones, antibiotics, and xenoestrogens found in conventionally-raised meats and dairy. Choose grass-fed and organic as much as possible.
- Decrease alcohol. Alcohol is associated with higher levels of estrogen and may impair the liver’s detoxification of estrogen.
- Reduce or eliminate coffee and caffeine. Caffeine intake, especially coffee, has been associated with higher levels of estrogen. Caffeine may cause the adrenals to release more cortisol. If this happens, the body may favor making more cortisol over making progesterone, and this can lead to an imbalance of estrogen. Reducing caffeine can help to lower cortisol levels, balance the adrenals, and improve the progesterone to estrogen ratio.
- Implement a Seed Rotation Diet. Here’s how:
- During the first half of the cycle (days 1-14), eat specific seeds to help the body produce estrogen – 2 tablespoons of fresh ground flax or pumpkin seeds per day.
- During the second half of the cycle (days 15-28), eat seeds that support progesterone production through zinc and vitamin E – 2 tablespoons of fresh ground sunflower seeds or sesame seeds per day.
This pattern can also be used by women in perimenopause or menopause, to support hormone balance.
- Stop using synthetic hormonal birth control or hormonal replacement therapy. Bio-identical hormones seem to offer a more gentle, and natural, alternative. Be sure to discuss the details of bio-identical hormones with your personal provider.
- Clean up your personal care and cleaning products in order to avoid exposure to xenoestrogens. Women, on average, use 12 personal care and cosmetic products per day, which amounts to 168 different chemical ingredients! These ingredients could be interfering with your hormones and causing toxicity in your body. You can use the Environmental Working Group’s Guide to Healthy Cleaning and Skin Deep Database to help you get started on finding healthy alternatives to your conventional personal care and cleaning products.
- Filter your water. Use a high quality water filter that filters out xenoestrogens and hormones from the water supply, for all drinking and cooking water. Also look for a filter that removes chlorine and fluoride to help support thyroid health, since these can interfere with thyroid hormone production.
- Prioritize sleep. Much of our detoxification happens during the sleeping hours, so sleep is key for removing excess estrogen from the body. Additionally, having a good production of melatonin (a hormone that helps to regulate your sleep-wake cycles) helps to lower estrogen.
- Sweat. Through exercise and saunas, sweating also plays a role in detoxifying the body from excess estrogen.
- Relax. Reducing stress is one of the best ways that you can support your sex hormones and thyroid hormones. Chronic stress can fatigue the adrenal glands, which control many of the hormones in the body. By balancing the adrenals, you can support progesterone production and a healthy estrogen to progesterone ratio.
- Consider supplements. Certain supplements, such as DIM (diindolylmethane), are helpful for estrogen dominance, specifically in the case of excess estrogen with normal levels of progesterone. DIM is a natural substance found in many cruciferous vegetables that can also be taken in capsule form. The therapeutic dose is 200 mg per day. Other supplements to consider include milk thistle, alpha lipoic acid, maca, and B vitamins. Another supplement that helps with balancing adrenal hormones and progesterone is pregnenolone, at a recommended dose of 10-30 mg per day. I am a big proponent of patient education and self management, and many of the above supplements are generally safe. However, it’s always best to check with your practitioner before using any of them. Furthermore, while I have often recommended pregnenolone to clients based on their test results, I never recommend using pregnenolone unless under the guidance of a trained professional.
More Resources to Reverse Estrogen Dominance
If you are ready to dive a little deeper, I highly recommend Overcoming Estrogen Dominance, the latest book from my friend and colleague Magdalena Wszelaki.
Overcoming Estrogen Dominance guides women out of estrogen dominance with recipes, meal plans, personalized protocols, recommended lab tests, and a guide to herbs and supplements. The book also features specific protocols for women with fibroids, breast lumps, thyroid nodules, period problems, and more.
Magdalena is a certified health and nutrition coach, herbalist, chef, and educator specializing in hormone imbalances. She and I met in 2013 after I reached out and told her how much I loved her work. I was so inspired by her empowering, can-do, practical methods for helping women get their health back, and thought to myself, “Wow, this woman is not just brilliant, but I’d love to have her as a friend!” I was so happy when she moved to Boulder, CO and we got to live close to each other and hang out. In the years since, I’ve learned so much from Magda (as I like to call her), as we often share ideas and best practices back and forth!
She, like so many other women, has a long history of hormonal challenges – from Graves’ disease and Hashimoto’s, to estrogen dominance. Today, however, Magdalena is happy to report she is in full remission and living a symptom-free life.
As you can see, a Root Cause approach works well for those with Hashimoto’s who also experience symptoms of estrogen dominance, as many of the underlying factors may be connected. If you are suffering from uncomfortable symptoms and suspect estrogen dominance may be playing a role, please work with your doctor for proper testing and know that the strategies in this article can play a helpful role in balancing and supporting your hormones.
I wish you all the best on your healing journey!
P.S. You can also download a free Thyroid Diet Guide, 10 Thyroid friendly recipes, and the Nutrient Depletions and Digestion chapter of my Hashimoto’s: Root Cause book for free, by signing up for my weekly newsletter. You will also receive occasional updates about new research, resources, giveaways, and helpful information.
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- 11 Ways Coffee Impacts Your Hormones and How to Substitute It. Hormones Balance website. https://hormonesbalance.com/articles/11-ways-coffee-impacts-your-hormones-and-how-to-substitute-it/. Published October 22, 2020. Accessed December 3, 2020.
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Note: Originally published in October 2015, this article has been revised and updated for accuracy and thoroughness.