Hashimoto's Thyroiditis - Symptoms, Causes, Treatment & Testing

March 4, 2021
October 21, 2021
5 minutes
Stefano Guandalini, MD

Medically reviewed by

Laura Tennant
Laura TennantLaura Tennant
Health and medical writer
Laura is a health and medical writer who works with medical, wellness, biotech and charity healthcare companies. Laura’s work has been published in the National Post, ALS Society of Canada, Leafly, and Diabetes Canada.
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Stefano Guandalini, MD
Stefano Guandalini, MD
Professor Emeritus at University of Chicago
Dr Guandalini is the former chief of pediatric gastroenterology, hepatology and nutrition at the University of Chicago, founder of the University of Chicago Celiac Disease Center and head of the clinical advisory team at imaware™.
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If you are experiencing symptoms of hypothyroidism, like tiredness, weight gain and depression, you may be wondering if you could have Hashimoto’s thyroiditis. Hashimoto’s thyroiditis is an autoimmune disorder that can cause hypothyroidism. It is more common among people who suffer from other autoimmune conditions, like celiac disease, lupus, rheumatoid arthritis, or type 1 diabetes, among others. 

Not all people with hypothyroidism have Hashimoto’s thyroiditis, but Hashimoto’s is the most common cause of hypothyroidism. Hashimoto’s disease is also believed to be the most common autoimmune disease. It is diagnosed about 8 times more often in women than in men.

To learn more about Hashimoto’s thyroiditis, we spoke with Dr. Stefano Guandalini, MD, Professor Emeritus at University of Chicago Medicine. 

What is Hashimoto’s Thyroiditis?

Hashimoto’s thyroiditis, or Hashimoto’s disease, is an autoimmune disorder that damages the thyroid. Hashimoto’s disease can cause hypothyroidism and it is recognized as the most common cause of hypothyroidism, or underactive thyroid, a condition where the thyroid does not make enough thyroid hormones to keep your metabolism regulated and your body healthy. 

Autoimmune disorders are caused by the body’s own immune system mistakenly attacking part of the body, causing illness. In Hashimoto’s disease, the body attacks the thyroid, causing damage that impairs its ability to function, and regulate metabolism leading to further health issues down the line. 

Symptoms of Hashimoto’s Thyroiditis

Hashimoto’s disease progresses slowly, and some people may have it without showing any symptoms at first. 

As Hashimoto’s progresses, people will start to show symptoms of hypothyroidism such as:

  • Fatigue
  • Weight gain
  • Muscle and joint pain
  • Constipation
  • Difficulty tolerating cold temperatures
  • Thinning hair
  • Depression
  • Brain fog
  • Enlarged tongue
  • Slower heart rate

Hashimoto’s thyroiditis vs. hypothyroidism: what’s the difference?

Hashimoto’s thyroiditis is a specific disease that causes the state of hypothyroidism. The concepts are related, but they are not identical.

Some people have hypothyroidism but not Hashimoto’s thyroiditis, but everyone who has Hashimoto’s thyroiditis has hypothyroidism. 

“There are many possible causes of hypothyroidism, and Hashimoto’s is just one of the possible causes,” Dr. Guandalini explains. 

“The difference between Hashimoto’s thyroiditis and hypothyroidism is that the term hypothyroidism simply means that someone has a low level of the thyroid hormones. It is a generic term, and it does not represent a specific disease entity,” he continues.

“However, the term Hashimoto’s indicates a specific disease: autoimmune thyroiditis.”

“A number of causes can lead to hypothyroidism, or reduced release of the hormones produced by the thyroid gland, including genetic birth defects, cancer, trauma, surgery on the thyroid gland, and autoimmune thyroiditis.” 

Other causes can include:

  • Medication
  • Pregnancy
  • Viral infection

Hashimoto’s thyroiditis testing

“If a person is showing signs or symptoms that could be attributed to Hashimoto’s thyroiditis, they should discuss this with their doctor and specific blood tests will be performed,” Dr. Guandalini explains.

Hashimoto’s thyroiditis is diagnosed with a combination of two tests:

1. TSH hormone test

A hormone blood test will check the levels of thyroid stimulating hormone (TSH) in the blood. This test is used to help diagnose hypothyroidism. The amount of this hormone in your blood can indicate an underactive or overactive thyroid.

2. Thyroid antibody test (TPOab)

If TSH tests indicate that a patient likely has hypothyroidism, they should be given an antibody test to check for thyroid peroxidase antibodies (TPOab). 

“TPO antibodies attack the enzyme thyroid peroxidase, which plays an important role in the production of T3 and T4,” Dr. Guandalini says.  

A positive TPO antibody test may indicate that Hashimoto’s is the cause of the patient’s hypothyroidism. 

Hashimoto’s vs. Graves’ Disease

It’s important to note that two autoimmune diseases can show elevated TPO antibodies - Hashimoto’s thyroiditis and Graves’ disease. However, Hashimoto’s causes hypothyroidism or underactive thyroid, while Graves’ disease causes hyperthyroidism or overactive thyroid. While they are both autoimmune diseases that affect the thyroid, the symptoms are different.

How is Hashimoto’s thyroiditis treated?

Thankfully, Hashimoto’s is relatively easy to manage - especially compared to Graves’ disease.

Hashimoto’s thyroiditis is an autoimmune disorder, which means the root cause of the disease is the body’s immune system attacking the thyroid. There is no reliable way to stop the progression of an autoimmune disease, although certain lifestyle factors, including diet and exercise may play a role in disease severity. 

While there is no cure for Hashimoto’s thyroiditis, doctors can treat the hypothyroidism caused by the disease. 

Hypothyroidism is typically treated with a medication called levothyroxine, which is a manufactured form of T4 or thyroxine. If this treatment is not enough, using other thyroid medications like T3 might be beneficial.

People who have elevated thyroid antibodies but do not show signs of hypothyroidism may not need to be treated, but should be monitored for progression of the disease, or for symptoms

Hashimoto’s and celiac disease: what’s the link?

There is a known link between celiac disease and Hashimoto’s thyroiditis. 

“It is estimated that about 3-5% of patients with Hashimoto's have celiac disease, and a similar percentage of celiac patients have Hashimoto's. The association is likely due to the shared genes favoring the development of autoimmunity,” Dr. Guandalini explained.

It stands to reason that the treatment for celiac disease, which is a gluten-free diet, might also help with Hashimoto’s. However, the jury is still out on whether this helps. 

A 2019 study found that a gluten-free diet significantly reduced the amount of thyroid antibodies in the blood among women with Hashimoto’s. However, the study was not placebo-controlled, cautioned Dr. Guandalini.  

“Every patient with Hashimoto's must be screened for celiac disease, and every celiac patient must be screened for Hashimoto's. Obviously, a strict gluten-free diet is mandatory for all patients with celiac disease, regardless of the presence of Hashimoto's.”

Read more in our guide to celiac disease and thyroid health.


Hashimoto’s thyroiditis is an autoimmune disorder causing hypothyroidism. It is diagnosed using two blood tests which identify hypothyroidism and autoimmune antibodies. 

If you or a loved one has symptoms of hypothyroidism, it is a good idea to get tested. A healthcare provider may order tests for antibodies if they believe Hashimoto’s could be the cause of hypothyroidism.


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