Did you know that women are more likely to form thyroid issues compared to men? Scientists reckon this may be from wavering estrogen levels in the female body, especially during menopause. So, if you need tools to support your hormonal balance, invaluable insights can be sought out with functional medicine from Toronto.

Personalized integrative medicine services are designed for biological needs. Opting for this “custom-made” approach to wellness may be beneficial for hormone struggles, as no patient’s body is identical to one another. Each patient can be thought of as a unique entity with distinctive genes, diets, nutrient levels, lifestyle and environmental factors. 

For tackling thyroid issues, some women are surprised to learn that fluctuating estrogen levels can affect thyroid function. Understanding this relationship between estrogen and the thyroid is significant for determining the “next steps” for treating hormone imbalances. 

This article from the Toronto Functional Medicine Centre highlights:

• • A review of what estrogen is and what your thyroid does. 
  • How estrogen instabilities affect thyroid function.
  • A synopsis of our functional medicine therapies and how we target hormonal imbalances. 

Recap: What does estrogen do?

In women, estrogen is the hormone accountable for sexual health and reproduction. It’s a chemical messenger that triggers the organs to begin or end bodily functions. Estrogen helps support your bones, cardiovascular needs, immune function, and nervous system, too, which means it can play a vital role in managing blood sugar levels, muscle mass, circulation, skin health, and brain care. 

Estrogen naturally increases or decreases in the body to accommodate “duties”, such as developing breasts during puberty, regulating monthly periods, and preparing the body for ovulation and aging. But estrogen amounts can be influenced by unhealthy lifestyle factors, too (i.e. lack of stress management, eating a poor diet, etc.). So, when the body faces high or low estrogen, widespread symptoms can appear in women, including infertility, acne, digestive issues, low libido, hot flashes, concentration issues, and vaginal dryness. 

Understanding thyroid function

Your thyroid is a gland that’s part of the endocrine system. Its main function is to regulate metabolism by secreting key hormones. These hormones—known as thyroid hormones—include thyroxine (T4), triiodothyronine (T3), and calcitonin. In addition, reverse T3 (rT3) is produced when T4 is converted into an inactive form in peripheral tissues. Because T4 is largely inactive, it must be converted into T3, the active hormone that directly impacts your body temperature, growth, fertility, heart rate, digestion system, weight management, and cognition. 

Due to the roles that thyroid hormones have, supporting thyroid health promotion is imperative as we age.In fact, the body requires optimal amounts of iodine to produce the thyroid hormones T4 and T3. However, the human body cannot synthesize iodine on its own, so this essential nutrient must be obtained from food sources or supplements.When iodine levels or thyroid hormone production become imbalanced, thyroid disorders can develop, most commonly an overactive thyroid (hyperthyroidism) or an underactive thyroid (hypothyroidism)

Estrogen dominance affects thyroid function – here’s how

So how does this interplay between estrogen and the thyroid work? Let’s look at estrogen dominance, which is when estrogen is excessively high compared to another hormone called progesterone. Quite simply, estrogen dominance doesn’t affect the thyroid organ itself, but rather the production of thyroid hormones. Estrogen dominance can halt T4 from altering into T3; in turn, this lessens T3 levels and may lead to hypothyroidism, which can cause fatigue, hair loss, depression, heavy periods, and constipation. 

This interplay between estrogen and the thyroid is noticed in some PCOS patients, as PCOS symptoms are influenced by high estrogen levels. Studies have shown that a high number of women with PCOS have a tendency to develop thyroid conditions, especially an autoimmune condition called Hashimoto’s thyroiditis. 

Does low estrogen impact your thyroid, too?

Yes — declining estrogen levels can influence thyroid function, though not usually by damaging thyroid tissue. When estrogen levels fall, thyroid-binding globulin (TBG) also decreases, altering the balance of free versus bound thyroid hormones. This shift can contribute to symptoms resembling hypothyroidism, such as fatigue, weight gain, or low mood, all of which can interfere with optimal wellness.

In addition, low estrogen may reduce the body’s sensitivity to thyroid hormones, meaning that even normal thyroid levels might not deliver optimal metabolic function. While estrogen decline doesn’t directly reduce thyroglobulin (Tg) or hormone production, it can significantly influence thyroid performance, energy metabolism, and overall wellness — especially during perimenopause or menopause.

At times, some of the symptoms of thyroid disorders and menopause overlap. A functional clinician can recommend laboratory testing to explore the underlying cause of your hormonal concerns; this can even provide insight into understanding if your estrogen levels and thyroid dysfunction are linked. Let’s explore this together at the Toronto Functional Medicine Centre, and we’ll introduce you to our integrated health care. 

Suggested reading: 10 Gut-Friendly Fruit Recommended by our Functional Medicine Toronto Providers

Learn more about our hormone balancing strategies 

Our integrative personalized medicine approach may be relevant for chronic disease conditions (i.e. chronic fatigue syndrome), cognitive concerns, widespread symptoms, enhancing muscle health for sports, and more. 

Our functional medicine practitioners have experience with several treatment modalities, including Western medicine, holistic/natural solutions (i.e. naturopathic medicine and homeopathic medicine, as well as botanical supplementation), psychotherapy, clinical nutrition, and Traditional Chinese Medicine. By adapting and combining these integrative treatment options, we can help tackle the root causes of your health issues; in turn, this can potentially support chronic disease prevention. And when several treatments are customized for one treatment plan, you have the convenience of drawing from these strategies at home. 

Our individualized, comprehensive approach to wellness is applied to hormonal concerns, too! We utilize functional lab tests (i.e. DUTCH testing) to closely scrutinize hormones, and we take your current lifestyle, diet, environmental factors, genes, and medical history into account for diagnoses and treatments. Hormone optimization programs are tailored just for your uniqueness, and may support health promotion with key nutraceuticals (i.e. antioxidants), hormone replacement therapy, and other healthy tools suited for your biology (i.e. bioidentical hormones). 

FYI: We’re happy to provide health education to patients, especially for comprehending lab results! Understanding details about your condition is beneficial for making lifestyle modifications, especially to recover from unhealthy lifestyle choices (i.e. Smoking, excessive alcohol consumption).

If you need help overcoming hormone obstacles, our clinic can conduct laboratory testing for your needs. It’s time to prioritize (and take charge) of your wellness now! Contact our Toronto area functional medicine clinic right now to request your initial consultation. 

Disclaimer: The information in this article is designed for educational purposes only and is not intended to be a substitute for informed medical advice or care. This information should not be used to diagnose or treat any health problems or illnesses without consulting a doctor. You should always consult with a health care practitioner before relying on any information in this article or on this website. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare provider because of information you have read from the Toronto Functional Medicine Centre website or other affiliate media. 

 

References

Delgado BJ, Lopez-Ojeda W. Estrogen. [Updated 2023 Jun 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538260/

Frank-Raue K, Raue F. Thyroid Dysfunction in Periand Postmenopausal Women-Cumulative Risks. Dtsch Arztebl Int. 2023 May 5;120(18):311-316. doi: 10.3238/arztebl.m2023.0069. PMID: 37013812; PMCID: PMC10398375.

Hu, X., Chen, Y., Shen, Y., Zhou, S., Fei, W., Yang, Y., & Que, H. (2022). Correlation between Hashimoto’s thyroiditis and polycystic ovary syndrome: A systematic review and meta-analysis. Frontiers in Endocrinology, 13, 1025267. https://doi.org/10.3389/fendo.2022.1025267

InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. In brief: How does the thyroid gland work? [Updated 2024 May 28]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279388/

Romitti, M., Fabris, V. C., Ziegelmann, P. K., Maia, A. L., & Spritzer, P. M. (2018). Association between PCOS and autoimmune thyroid disease: A systematic review and meta-analysis. Endocrine Connections, 7(11), 1158. https://doi.org/10.1530/EC-18-0309

Saran, S., Gupta, B. S., Philip, R., Singh, K. S., Bende, S. A., Agroiya, P., & Agrawal, P. (2016). Effect of hypothyroidism on female reproductive hormones. Indian Journal of Endocrinology and Metabolism, 20(1), 108. https://doi.org/10.4103/2230-8210.172245

Santin, A. P., & Furlanetto, T. W. (2011). Role of Estrogen in Thyroid Function and Growth Regulation. Journal of Thyroid Research, 2011, 875125. https://doi.org/10.4061/2011/875125

Singla R, Gupta Y, Khemani M, Aggarwal S. Thyroid disorders and polycystic ovary syndrome: An emerging relationship. Indian J Endocrinol Metab. 2015 Jan-Feb;19(1):25-9. doi: 10.4103/2230-8210.146860. PMID: 25593822; PMCID: PMC4287775.