What Causes Your Thyroid to Be Underactive? (2022)

Hypothyroidismmay develop for a number of different reasons, the most common beingan autoimmune attack on the thyroid gland,called Hashimoto's thyroiditis. Hypothyroidism may also be the result oftaking a medication like lithium, genetics,or anunderlying pituitary gland problem.

Understanding the "why" behind a diagnosis of hypothyroidism is critical to moving forward with a proper treatment plan. While some people may require lifelong thyroid hormone replacement, others may have a short-lived case of hypothyroidism (for example, postpartum thyroiditis), need to stop taking a medication, or require further diagnostic tests like imaging of the pituitary gland.

What Causes Your Thyroid to Be Underactive? (1)

Common Causes

Hashimoto's thyroiditis is the leading cause of hypothyroidism in the United States.

In Hashimoto's, antibodies react against proteins in your thyroid gland, causing gradual destruction of the gland itself,rendering it unable to produce the thyroid hormones your body needs.

Hashimoto's thyroiditis is more common in women, and while it may occur at any age, it's more common as people get older. For women, Hashimoto's often develops during pregnancy, after delivery, or around the time of menopause.

Antibodies attack thyroid gland cells, affecting function and size.What Causes Your Thyroid to Be Underactive? (2)

Other causes of hypothyroidism include:


People with hyperthyroidism, thyroid nodules, or thyroid cancer may need to have surgery. If all of the thyroid gland is surgically removed, a person will be hypothyroid and require lifelong thyroid hormone replacement medications. If only part of the thyroid gland is removed, there is a good chance that it will still be able to make sufficient thyroid hormone.

An Overview of Thyroid Surgery


Instead of thyroid surgery or antithyroid medication, some people with hyperthyroidism are treated with radioactive iodine, which will destroy the thyroid gland, rendering a person hypothyroid. People who undergo radiation treatment for Hodgkin's lymphoma or head and neck cancer are also at risk of developing hypothyroidism.


Thyroiditis describes thyroid gland inflammation and is a general term for a variety of thyroid conditions.

Hashimoto's disease is the most common type of thyroiditis and is caused by an autoimmune attack.

(Video) SIGNS THAT YOU HAVE A LOW THYROID LEVEL - Hypothyroidism Symptoms

Another example of thyroiditis is subacute thyroiditis (also called de Quervain's thyroiditis), which is believed to be caused by a virus. With this type of thyroiditis, a person experiences hyperthyroidism followed by hypothyroidism, in addition to a tender thyroid gland.

The Different Types of Thyroiditis

Certain Drugs

Certain medications maytrigger hypothyroidism. These medications include:

  • Lithium
  • Amiodarone
  • Thionamides (antithyroid drugs)
  • Interferon-alpha
  • Interleukin-2
  • Certain cancer drugs (tyrosine kinase inhibitors and checkpoint inhibitor immunotherapies)

Iodine Excess or Deficiency

Too much iodine(for example, from dietary supplements that contain kelp) can cause or worsen hypothyroidism. In addition, a deficiency of iodine, which is seen in some people in underdeveloped countries, may cause hypothyroidism. Iodine is necessary for the production of thyroid hormone and is found in foods, like dairy products, chicken, beef, pork, fish, and iodized salt.

Congenital Hypothyroidism

Some babies are born without a thyroid gland or with only a partial thyroid gland. Since there is no thyroid gland (or not enough) to produce thyroid hormone, hypothyroidism develops, which is serious and requires treatment with a thyroid hormone pill.

What to Expect When Your Baby Has Hypothyroidism

Pituitary Gland Problem

The pituitary gland is located in the brain and stimulates other glands within the body, like the thyroid gland, to release hormones. If the pituitary gland is damaged by a brain tumor, radiation, or brain surgery, it may not function well enough to signal the thyroid gland. This canthen result in it becomingunderactive. This type of hypothyroidism is called central or secondary hypothyroidism.

Infiltrative Diseases

Rarely, certain diseases, like hemochromatosis, can deposit abnormal substances (iron, in the case of hemochromatosis)in your pituitary gland, causing central hypothyroidism, or less commonly, your thyroid gland, causing primary hypothyroidism.

Besides hemochromatosis, sarcoidosis can cause granuloma deposition in the thyroid gland. There is also a rare condition called fibrous thyroiditis (or Riedel's thyroiditis), in which fibrotic tissue replaces normal thyroid tissue.


Your DNA plays a role when it comes to developing autoimmune hypothyroidism, and this has been supported by a number of studies.

OneGerman study found a 32-fold increased risk for developing Hashimoto's thyroiditis in children and a 21-fold increased risk in siblings of people with Hashimoto's thyroiditis.

When looking at the specific genes linked to Hashimoto's, scientists have found mutations in the genes for human leukocyte antigen (HLA), T-cell receptors, and other molecules involved in the immune system.

To further support the role of genes in developing Hashimoto's thyroiditis, people withTurner syndrome and Down syndrome (both of which are genetic in origin) have a higher than expected rate of autoimmune thyroid disease, especially Hashimoto's thyroiditis.

(Video) How a thyroid gland can become underactive

All said, though, it's important to remember that your genes are but one factor that help predictyour risk of developing hypothyroidism. There are many other factors that come into play, like pregnancy or taking certain medications.

In the end, it's the combination of genes and an environmental trigger that predict a person's unique risk for developing hypothyroidism.

Risk Factors

Factors that increase a person's risk of developing hypothyroidism include:

  • Being female
  • Being of an older age
  • Being Caucasian or Asian
  • Having a family history of Hashimoto's thyroiditis or another autoimmune disease
  • Having a personal history of an autoimmune disease (for example, adrenal insufficiency, rheumatoid arthritis, or type 1 diabetes)
  • Being pregnant or postpartum
  • Too much or too little iodine consumption
  • Treated with radioactive iodine
  • Received radiation to the neck or upper chest
  • Underwent thyroid surgery
  • Treated with certain medications (for example, lithium for bipolar disorder)

Evolving Risk Factors

Interestingly,research suggests that selenium deficiency may be linked to developing Hashimoto's thyroiditis and hypothyroidism. Moreover, having underlying headache disorders, like migraines, has been found to be associated with an increased risk of hypothyroidism, especially in obese women.

It's still unclear precisely how smoking affects the thyroid gland, although it's likely complex. While somestudies suggest that cigarette smoking increases the risk of hypothyroidism in people with Hashimoto's thyroiditis, other research suggests that smoking is actually linked to a lower prevalence of hypothyroidism and a higher prevalence of hyperthyroidism.

How Healthcare Providers Diagnose Hypothyroidism

Frequently Asked Questions

  • Why is hypothyroidism more common in women?

    The most common cause of hypothyroidism is an autoimmune condition called Hashimoto disease, and women are more likely to be affected by autoimmune conditions in general. One reason may be that hormones play a significant role in the functions affected by autoimmune conditions, and women experience more shifts in hormones during their lifetime.

  • What increases your chances of getting Hashimoto disease?

    Having another autoimmune condition such as rheumatoid arthritis is one factor that puts you at risk for Hashimoto thyroiditis. A family history of the disease also increases your risk. Women are seven times more likely than men to develop Hashimoto disease.

    (Video) Hypothyroidism | Under-Active Thyroid | What All Patients Need to Know

9 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

(Video) Thyroid problems - most common thyroid problems, symptoms and treatment

  1. Hashimoto's Disease. National Institute of Diabetes and Digestive and Kidney Diseases. Sept 1, 2017.

  2. Miller MC, Agrawal A. Hypothyroidism in postradiation head and neck cancer patients: incidence, complications, and management. Current Opinion in Otolaryngology & Head and Neck Surgery. 2009;17(2):111-115. doi:10.1097/moo.0b013e328325a538.

  3. Chakera AJ, Pearce SH, Vaidya B. Treatment for primary hypothyroidism: current approaches and future possibilities. Drug Des Devel Ther. 2012;6:1-11. doi:10.2147/DDDT.S12894

  4. Panicker V. Genetics of thyroid function and disease. Clin Biochem Rev. 2011;32(4):165-75.

  5. Dittmar M, Libich C, Brenzel T, Kahaly GJ. Increased familial clustering of autoimmune thyroid diseases. Horm Metab Res. 2011;43(03):200-204.doi:10.1055/s-0031-1271619

  6. Aversa T, Lombardo F, Valenzise M, et al. Peculiarities of autoimmune thyroid diseases in children with Turner or Down syndrome: an overview. Ital J Pediatr. 2015;41:39. doi:10.1186/s13052-015-0146-2

  7. Hypothyroidism - A Booklet for Patients and their Families. American Thyroid Association. 2013.

  8. Angum F, Khan T, Kaler J, Siddiqui L, Hussain A. The prevalence of autoimmune disorders in women: a narrative review. Cureus. 2020 May;12(5):e8094. doi:10.7759/cureus.8094

  9. Johns Hopkins Medicine. Hashimoto's thyroiditis.

Additional Reading


What Causes Your Thyroid to Be Underactive? ›

Most cases of an underactive thyroid are caused by the immune system attacking the thyroid gland and damaging it, or by damage that occurs as a result of treatments for thyroid cancer or an overactive thyroid

overactive thyroid
An overactive thyroid, also known as hyperthyroidism or thyrotoxicosis, is where the thyroid gland produces too much of the thyroid hormones. The thyroid is a small butterfly-shaped gland in the neck, just in front of the windpipe (trachea).
https://www.nhs.uk › overactive-thyroid-hyperthyroidism

Is underactive thyroid serious? ›

If an underactive thyroid is not treated, it can lead to complications, including heart disease, goitre, pregnancy problems and a life-threatening condition called myxoedema coma (although this is very rare).

What happens when your thyroid is low? ›

Hypothyroidism is a common condition where the thyroid doesn't create and release enough thyroid hormone into your bloodstream. This makes your metabolism slow down. Also called underactive thyroid, hypothyroidism can make you feel tired, gain weight and be unable to tolerate cold temperatures.

Can underactive thyroid go back to normal? ›

In summary, the most important aspect of thyroid disease is that effective treatments are available that can restore thyroid function to normal, even if the underlying cause of the disorder is not “cured”.

Does underactive thyroid ever go away? ›

Occasionally, the condition may resolve without treatment. Follow-up appointments are important to monitor hypothyroidism over time, however. If hypothyroidism doesn't go away on its own within several months, then treatment is necessary. If left untreated, this condition eventually may lead to serious health problems.

What foods to avoid if you have underactive thyroid? ›

What to limit or avoid
  • Iodine. Your thyroid needs iodine to make its hormones. ...
  • Soy. Soy-based foods like tofu and soybean flour are high in protein, low in fat, and rich in nutrients. ...
  • Fiber. ...
  • Cruciferous vegetables. ...
  • Alcohol. ...
  • Gluten. ...
  • Iron and calcium.

How can I boost my thyroid naturally? ›

Thyroid Superfoods
  1. Roasted seaweed. Seaweed, such as kelp, nori, and wakame, are naturally rich in iodine--a trace element needed for normal thyroid function. ...
  2. Salted nuts. Brazil nuts, macadamia nuts, and hazelnuts are excellent sources of selenium, which helps support healthy thyroid function. ...
  3. Baked fish. ...
  4. Dairy. ...
  5. Fresh eggs.
Jan 11, 2018

What are the first signs of underactive thyroid? ›

Symptoms of an underactive thyroid
  • tiredness.
  • being sensitive to cold.
  • weight gain.
  • constipation.
  • depression.
  • slow movements and thoughts.
  • muscle aches and weakness.
  • muscle cramps.

What are early warning signs of thyroid problems? ›

7 Early Warning Signs of Thyroid Issues
  • Fatigue.
  • Weight gain.
  • Weight loss.
  • Slowed heart rate.
  • Increased heart rate.
  • Sensitivity to heat.
  • Sensitivity to cold.
Jan 11, 2021

What are 3 symptoms of hypothyroidism? ›

Hypothyroidism signs and symptoms may include:
  • Fatigue.
  • Increased sensitivity to cold.
  • Constipation.
  • Dry skin.
  • Weight gain.
  • Puffy face.
  • Hoarseness.
  • Muscle weakness.
Nov 19, 2020

Is hypothyroidism caused by stress? ›

Cortisol, the main hormone produced in response to stress, can suppress pituitary function and keep the thyroid-stimulating hormone (TSH) from being released, thereby inducing hypothyroidism, according to Dr. Wasser.

Does hypothyroidism make you look older? ›

If your thyroid gland is under active, this usually causes your skin to become dry. Fine lines and wrinkles appear earlier and are more noticeable. It is well known that an under active thyroid gland will age you more rapidly.

Is coffee good for thyroid? ›

Coffee: Time Your First Cup Carefully in the Morning

Per a study in the journal Thyroid, caffeine has been found to block absorption of thyroid hormone replacement. "People who were taking their thyroid medication with their morning coffee had uncontrollable thyroid levels, and we couldn't figure it out," says Dr. Lee.

Is banana good for thyroid? ›

Hypothyroid persons can take all fruits including banana in moderation.

What vitamins help with thyroid? ›

Iodine. Iodine is critical for thyroid function. In fact, currently, the only known role of iodine is to support thyroid hormone production. Triiodothyronine (T3) and thyroxine (T4) are thyroid hormones that contain iodine.

What fruits are good for your thyroid? ›

Apples, pears, plums and citrus fruits are abundant with pectins, which help with detoxifying the body of mercury – one of the most critical metals that have been connected to thyroid problems.

What is the best breakfast for hypothyroidism? ›

Aim for a breakfast that includes all the food groups: whole grains, meat or beans, vegetables, fruit and dairy. For grains, choose oatmeal, whole grain cereal, granola, whole wheat pancakes or a whole wheat tortilla. Make a breakfast burrito with scrambled egg whites and sauteed vegetables.

What food is good for thyroid? ›

Thyroid and diet factsheet
  • eat at least 5 portions of a variety of fruit and vegetables every day.
  • base meals on higher fibre starchy foods like potatoes, bread, rice or pasta.
  • have some dairy or dairy alternatives.
  • eat some beans, pulses, fish, eggs, meat and other protein.
Oct 7, 2019

How can I check my thyroid at home? ›

How to Do a Self Thyroid Exam - YouTube

At what age do thyroid problems start? ›

Having too much of these hormones can cause unpleasant and potentially serious problems that may need treatment. An overactive thyroid can affect anyone, but it's about 10 times more common in women than men, and typically happens between 20 and 40 years of age.

What causes thyroid problems in females? ›

Approximately 1 in 8 women will be affected by a thyroid condition at some point in their lives. The risk for women is about 10 times higher than for men. One reason for this is that thyroid disorders are often triggered by autoimmune responses, which happen when the body's immune system starts to attack its own cells.

Does thyroid affect sleep? ›

If your thyroid makes too little hormone, it's a more common condition called hypothyroidism. You might have trouble falling asleep or not be able to stay asleep long enough to feel fully rested. Hypothyroidism also can affect your sleep by making you feel too cold or causing joint or muscle pain.

Can thyroid problems be cured? ›

Can hyperthyroidism be cured? Yes, there is a permanent treatment for hyperthyroidism. Removing your thyroid through surgery or destroying your thyroid through medication will cure hyperthyroidism.

What can make hypothyroidism worse? ›

6 Habits to Avoid If You Have Hypothyroidism
  • Missing your thyroid medication. ...
  • Using different brands of thyroid medication. ...
  • Traveling without your thyroid medication. ...
  • Mixing food with your thyroid medication. ...
  • Eating soy with your thyroid medication. ...
  • Not managing your weight.
Feb 17, 2017

What can I do to help my underactive thyroid? ›

Treatment for an underactive thyroid involves taking daily hormone replacement tablets, called levothyroxine, to raise your thyroxine levels. You'll usually need treatment for the rest of your life. However, with proper treatment, you should be able to lead a normal, healthy life.

How much sleep do I need with hypothyroidism? ›

Get Smart About Sleep

You might feel run down, even if you're taking medication. Yet all too often, “people with hypothyroidism don't get enough sleep, or the sleep they're getting isn't good quality,” Hatipoglu says. To ensure your body has a chance to rest and recover: Aim for 8 hours of sleep every night.

What are early warning signs of thyroid problems? ›

7 Early Warning Signs of Thyroid Issues
  • Fatigue.
  • Weight gain.
  • Weight loss.
  • Slowed heart rate.
  • Increased heart rate.
  • Sensitivity to heat.
  • Sensitivity to cold.
Jan 11, 2021

How common is underactive thyroid? ›

Both men and women can have an underactive thyroid, although it's more common in women. In the UK, it affects 15 in every 1,000 women and 1 in 1,000 men. Children can also develop an underactive thyroid. Around 1 in 3,500-4,000 babies are born with an underactive thyroid (congenital hypothyroidism).

At what age do thyroid problems start? ›

Having too much of these hormones can cause unpleasant and potentially serious problems that may need treatment. An overactive thyroid can affect anyone, but it's about 10 times more common in women than men, and typically happens between 20 and 40 years of age.

What are the symptoms of underactive thyroid in females? ›

Symptoms of an underactive thyroid
  • tiredness.
  • being sensitive to cold.
  • weight gain.
  • constipation.
  • depression.
  • slow movements and thoughts.
  • muscle aches and weakness.
  • muscle cramps.

What causes thyroid problems in females? ›

Autoimmune disease.

The most common cause of hypothyroidism is an autoimmune disorder known as Hashimoto's thyroiditis. Autoimmune disorders occur when your immune system produces antibodies that attack your own tissues. Sometimes this process involves your thyroid gland.

Can stress cause thyroid problems? ›

Stress alone will not cause a thyroid disorder, but it can make the condition worse. The impact of stress on the thyroid occurs by slowing your body's metabolism. This is another way that stress and weight gain are linked.

What is the life expectancy of someone with an underactive thyroid? ›

What are the longer-term implications of hypothyroidism? People who are treated with levothyroxine have a normal life expectancy and lead a normal life. One of the commonest long-term problems is that it is easy to forget to take tablets regularly.

How do I know if my underactive thyroid is getting worse? ›

Symptoms of severe overtreatment include:
  1. Anxiety.
  2. Mood swings.
  3. Hand tremors.
  4. Diarrhea.
  5. Muscle weakness, mainly in the thighs and shoulders.
  6. Weight loss.
  7. Inability to sleep and/or focus.
  8. Abnormally increased heart rate, even at rest.
Sep 9, 2020

Does hypothyroidism make you look older? ›

If your thyroid gland is under active, this usually causes your skin to become dry. Fine lines and wrinkles appear earlier and are more noticeable. It is well known that an under active thyroid gland will age you more rapidly.

Does underactive thyroid get worse with age? ›

The prevalence of subclinical hypothyroidism increases with aging and ranges from 3 to 16 % in individuals aged 60 years and older [1].


1. Signs of Low Thyroid Level (Hypothyroidism), & Why Symptoms Occur
(JJ Medicine)
2. What is Thyroid Disease? (HealthSketch)
3. Cure Thyroid Problem Permanently in 4 Steps (100% Guaranteed)
(Fit Tuber)
4. My Underactive Thyroid Won't Let Me Lose Weight | This Morning
(This Morning)
5. Hyperthyroidism & Thyroid Storm Signs & Symptoms (& Why They Occur)
(JJ Medicine)
6. The Underactive and Overactive Thyroid | Stephanie Smooke, MD, and Angela Leung, MD | UCLAMDChat
(UCLA Health)

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