It is clear that a connection between hypothyroidism and PCOS exists. Both hypothyroidism and PCOS are common endocrine disorders in women. Although they are very different, many of the signs and symptoms are the same. This makes it easy to be misdiagnosed.

It is also possible to have both disorders. In fact, one study showed 11.3% of study participants with PCOS had subclinical hypothyroidism (1), and another showed 22.1% of study participants with PCOS had Hashimoto’s (the autoimmune hypothyroidism) (2).

What is the thyroid?

The thyroid is a butterfly-shaped gland that makes hormones that essentially every single cell in the body needs to function correctly, and play roles in body temperature regulation, heart rate, metabolism, menstrual cycle regularity, and blood pressure. 

Thyroid Disorders + Diagnosis

A thyroid that is not working properly either overproduces (hyperthyroidism) or underproduces (hypothyroidism) hormones. Hypothyroidism or Hashimoto’s thyroiditis (the autoimmune hypothyroidism) often coincides with PCOS. 

Diagnosis of thyroid disorders should be based on a full assessment of symptoms, labs, and a physical exam by a qualified medical professional. 

Also know that Hashimoto’s thyroiditis is the leading cause of hypothyroidism. This is an immune system response caused by genetic and environmental triggers.

Thyroid Hormones

TSH (thyroid stimulating hormone): This hormone is actually not produced by the thyroid. It comes from the brain and tells the thyroid to make hormones, like T4. If TSH is high, it could indicate hypothyroidism. Often this is the lab that is most often ordered by doctors, but doesn’t always tell the whole story. Ask for a full thyroid panel.

Free T4: This is the inactive and unbound thyroid hormone, which eventually gets converted to T3. 

Free T3: This is the active thyroid hormone that is available to be used by cells. 

Reverse T3: This stops T4 from converting to T3. 

TPO and Thyroglobulin Antibodies: Measures thyroid antibodies that are being produced as an autoimmune response. Those with Hashimoto’s thyroiditis will have elevated antibodies. This could be elevated, even if TSH is “normal”.

Hypothyroidism Signs and Symptoms

Like PCOS, people with hypothyroidism can experience a different variety of symptoms than others with the same diagnosis. 

Symptoms of hypothyroidism may include fatigue, hair loss, weight gain/difficulty losing weight, slow than normal heart rate, low body temp, constipation or other gut issues, menstrual cycle irregularity, infertility, joint pain, muscle weakness, high cholesterol, and depression/anxiety.

Hypothyroidism and Your Menstrual Cycle

Thyroid hormones are needed for every cell in the body! Your ovaries need it, too. Thyroid hormones are needed for follicular development and ovulation, as well as communication between the brain and ovaries. 

Hypothyroidism may affect pituitary hormone levels like LH, FSH, and prolactin (4). It is also associated with decreased SHBG, increased estrogen, and increased testosterone levels (5). 

This may contribute to anovulation, heavy periods, irregular periods, and difficulty conceiving or sustaining pregnancy. 

What’s the hypothyroidism and PCOS connection?

As stated previously, the prevalence of hypothyroidism and specifically Hashimoto’s thyroiditis, is higher in those with PCOS (1,2).

There is a possible connection between the estrogen and progesterone levels correlating to the higher levels of TPO-antibodies. However, it is still unclear exactly how they correlate to one another (2).

Insulin resistance and inflammation are major contributors to the pathophysiology of PCOS. These may also contribute to hypothyroidism.

At the same time, hypothyroidism may contribute to insulin resistance as well (6). Additionally, the hormone imbalances caused by hypothyroidism are similar to the imbalances shown in PCOS.

In addition, like PCOS, Hashimoto’s may be triggered by certain genetic and environmental factors.

Could PCOS be misdiagnosed as hypothyroidism or vice versa?

With so many similarities, it could be easy to miss hypothyroidism as a piece of the puzzle, or be misdiagnosed with PCOS instead or vice versa. It’s important to test for hypothyroidism if PCOS is suspected. 

Treatments for Hypothyroidism

You must have adequate thyroid hormones, so a doctor will likely prescribe thyroid hormone replacement medications like levothyroxine.

Assessing and addressing triggers like gut health, insulin resistance, stress and others, may help to reduce symptoms. 

If Hashimoto’s is the cause of hypothyroidism, calming the body’s immune system and inflammatory responses through nutrition and lifestyle changes is helpful.

Supplementation under supervision of a doctor and/or dietitian could be helpful to reduce symptoms and even reduce antibodies. 

Nutrition for Hypothyroidism and PCOS

Blood sugar balance

As with PCOS, insulin resistance is correlates with thyroid issues. Eating for balanced blood sugar can help. This includes eating regular meals throughout the day and including protein + fat + fiber at those meals and snacks. 

Anti-inflammatory foods

Chronic inflammation is part of the pathophysiology of PCOS and thyroid issues, especially Hashimoto’s. Choosing nutrient dense foods high in antioxidants, omega-3s, and fiber may help with inflammation.


Unlike false claims that a gluten-free diet is the ticket to improving PCOS, it actually *might* be helpful for those with Hashimoto’s by helping to lower antibodies (3). This is something you can trial and see what happens. If it causes you even more stress, it may not be for you. Testing for Celiac disease can rule out gluten intolerance. 

Gut support

Gut health affects the immune system. Address any existing gut health issues to support the thyroid. A GI map stool test may be helpful to determine exactly what’s going on in the gut.

Nutrients to support the thyroid

Nutrients like zinc, selenium, omega-3s, magnesium, iron, B-vitamins, iodine, and vitamin A are important for thyroid health. Selenium in particular is essential to convert T4 to T3 and may also help to reduce antibodies. 

If you suspect or are diagnosed with hypothyroidism and PCOS, apply for the 1:1 Peace with PCOS Experience to get individualized coaching.

how to improve hypothyroidism with PCOS


  1. Singla, R., Gupta, Y., Khemani, M., & Aggarwal, S. (2015). Thyroid disorders and polycystic ovary syndrome: An emerging relationship. Indian journal of endocrinology and metabolism, 19(1), 25–29.
  1. Arduc, A., Aycicek Dogan, B., Bilmez, S., Imga Nasiroglu, N., Tuna, M. M., Isik, S., Berker, D., & Guler, S. (2015). High prevalence of Hashimoto’s thyroiditis in patients with polycystic ovary syndrome: does the imbalance between estradiol and progesterone play a role?. Endocrine research, 40(4), 204–210.
  1. Krysiak R, Szkróbka W, Okopień B. The Effect of Gluten-Free Diet on Thyroid Autoimmunity in Drug-Naïve Women with Hashimoto’s Thyroiditis: A Pilot Study. Exp Clin Endocrinol Diabetes. 2019 Jul;127(7):417-422. doi: 10.1055/a-0653-7108. Epub 2018 Jul 30. PMID: 30060266.
  2. Nath, C. K., Barman, B., Das, A., Rajkhowa, P., Baruah, P., Baruah, M., & Baruah, A. (2019). Prolactin and thyroid stimulating hormone affecting the pattern of LH/FSH secretion in patients with polycystic ovary syndrome: A hospital-based study from North East India. Journal of family medicine and primary care8(1), 256–260.
  3. Kjaergaard, A. D., Marouli, E., Papadopoulou, A., Deloukas, P., Kuś, A., Sterenborg, R., Teumer, A., Burgess, S., Åsvold, B. O., Chasman, D. I., Medici, M., & Ellervik, C. (2021). Thyroid function, sex hormones and sexual function: a Mendelian randomization study. European journal of epidemiology36(3), 335–344.
  4. Gierach, M., Gierach, J., & Junik, R. (2014). Insulin resistance and thyroid disorders. Endokrynologia Polska65(1), 70–76.