Hypothyroidism

What Is Hypothyroidism? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Kristeen Cherney, PhD
By Medically Reviewed by 
Reviewed:
Medically Reviewed
Hypothyroidism is a condition that occurs when your thyroid gland doesn’t produce enough thyroid hormones.

There are many glands in the body; the thyroid gland is the small butterfly-shaped organ at the base of your neck that makes hormones that regulate your metabolism — which affects how the body uses energy — and other processes.

While your body goes through hormonal changes every day (hello, mood swings!), big dips like those that occur during hypothyroidism can signal danger, as a lack of thyroid hormone production causes the body’s functions to slow down.

Not to mention, an underactive or overactive thyroid (called hyperthyroidism) can affect your waistline. People with hypothyroidism experience a slower metabolic rate, which is generally associated with some amount of weight gain, about 5 to 10 pounds, usually due to accumulation of salt and water in the body.

Signs and Symptoms of Hypothyroidism

The signs and symptoms of hypothyroidism often develop slowly over the years and may be mistaken for the natural changes of aging.

Hypothyroidism Symptoms in Adults

Look out for these potential symptoms of hypothyroidism:

Hypothyroidism Symptoms in Infants

Hypothyroidism is most common in middle-aged and older women. But sometimes infants and children can develop the condition, such as infants who were born without a thyroid gland or who have a thyroid gland that doesn’t function properly.

Congenital hypothyroidism occurs in about 1 in 2,000 to 4,000 newborns.

If undiagnosed, it can lead to increasingly severe symptoms and even physical and mental disabilities.

Hypothyroidism in infants may include these symptoms:

  • Jaundice (yellowing of the skin and whites of the eyes)
  • Frequent choking
  • Puffy face
  • Constipation
  • Delays in growth or reaching growth milestones

Common Questions & Answers

What happens if hypothyroidism is left untreated?
Left untreated, hypothyroidism can cause reproductive issues, high cholesterol, depression, weight gain, and chronic constipation. There’s no cure for hypothyroidism, so it’s important to remain vigilant about taking your thyroid meds (thyroxine) and getting your levels checked regularly.
What level of TSH indicates hypothyroidism?
Normal thyroid-stimulating hormone (TSH) levels can vary by lab but generally can range between 0.4 and 4 milliunits per liter. Sometimes a lower TSH is targeted in women trying to get pregnant. A TSH above the normal range should be confirmed with repeat testing but may indicate hypothyroidism or inadequate dose of levothyroxine (synthetic thyroxine).
Can you lose weight if you have hypothyroidism?
The amount of hypothyroid-related weight gain is usually modest, about 5 to 10 pounds at most. As you undergo treatment and get the right amount of thyroid hormones, your basal metabolic rate will increase to baseline so that you’ll be able to lose any extra pounds you gained previously.
What are the symptoms of thyroid problems in women?
Aside from common symptoms of hypothyroidism, such as excessive tiredness, hair loss, muscle weakness, and weight gain, women can experience reproductive symptoms, too. These include heavier menstrual periods as well as infertility.
Can you live a long life with hypothyroidism?
Absolutely. When managed, hypothyroidism isn’t life-threatening. Still, it is possible to develop complications from hypothyroidism that is untreated (or even undertreated), which may in turn affect your overall quality of life. Some of these complications include depression, high cholesterol, and heart disease.

Hypothyroidism Symptoms in Children and Teens

Symptoms of hypothyroidism in children and teens are similar to symptoms in adults and can include the following:

  • Poor growth or short stature
  • Delayed puberty
  • Slow reaction time
  • Weight gain
  • Coarse, dry hair or skin
  • Muscle cramps
  • Delayed mental development
  • Increased menstrual flow (in girls)

Learn More About the Signs and Symptoms of Hypothyroidism

Causes and Risk Factors of Hypothyroidism

Anyone can develop hypothyroidism, but you’re at higher risk for it if you’re a woman older than 60.

  • Having a family history of thyroid disease
  • Having other autoimmune diseases (such as rheumatoid arthritis, type 1 diabetes, or lupus)
  • Taking supplements and medications that affect the thyroid, including iodine and lithium
  • Having undergone thyroid surgery
  • Having a history of exposure to radiation to your neck or upper chest
  • Having been pregnant or delivered a baby within the past six months

What You Should Know About Hashimoto’s Thyroiditis

Hashimoto’s thyroiditis is a condition in which your immune system attacks your thyroid gland, often causing hypothyroidism.

It’s the most common cause of underactive thyroid in the United States.

Hashimoto’s thyroiditis typically affects middle-aged women, but it can happen in anyone. It affects about 5 in 100 people and is 8 times more common in women than men.

About 10 to 12 percent of the population has the antibodies that cause Hashimoto’s thyroiditis, but not all of these individuals will develop thyroid dysfunction.

Currently, the causes of Hashimoto’s thyroiditis are unknown, but experts think they may be due to a combination of genes and an external trigger, like a virus.

Doctors can detect the condition by testing your thyroid function. Treatment usually involves thyroid hormone replacement medication.

Iodine Intake

Your thyroid gland must have correct amounts of the mineral iodine to make thyroid hormones.

Consuming too little iodine can lead to hypothyroidism. Too much iodine may also cause or worsen hypothyroidism.

Iodine is found in foods such as seaweed, seafood, and iodized salt.

In some areas of the world, iodine deficiency is common, but it’s rare in the United States because most forms of table salt are fortified with the mineral. So iodine levels are not routinely tested in the evaluation for hypothyroidism.

Thyroidectomy

A thyroidectomy, surgery to remove all or part of your thyroid gland, can slow or stop the production of thyroid hormones and cause hypothyroidism. The operation is fairly common: More than 150,000 patients in the United States receive a thyroidectomy each year (the most common cause for surgery was cancer).

People with thyroid cancer, a goiter (an enlarged thyroid), thyroid nodules, or Graves’ disease may need to undergo this procedure.

Learn More About the Causes of Hypothyroidism: Common Risk Factors, Genetics and More

How Is Hypothyroidism Diagnosed?

If you have many of the common symptoms of hypothyroidism, such as dry skin, constipation, fatigue, and a hoarse voice, you can make an appointment with your doctor to check for hypothyroidism.

Your doctor can perform various screenings:

  • A physical exam
  • A blood test
  • An imaging scan

If these tests show an elevated thyroid-stimulating hormone (TSH) and low levels of thyroid hormones — like free T4, total T3, or free T3 — it may be an indication that you have hypothyroidism, says Mayumi Endo, MD, an endocrinologist in Seattle.

How to Prepare for an Upcoming Doctor’s Appointment for Hypothyroidism

Aside from conducting a physical exam, blood test, and possible thyroid-imaging scan, your doctor will ask you extensive questions about your symptoms and how long you’ve been experiencing them. Here’s how to prepare for your upcoming doctor’s appointment:

Keep a journal that details your symptoms and their severity. Bring your notes to your appointment to share with your doctor. This can help the doctor detect patterns in your hypothyroid symptoms and get a better idea of which screenings you may need for a proper diagnosis.

Bring a list of the vitamins, herbal supplements, and prescription or over-the-counter medications you currently take. These items may interact with your treatment regimen, so your doctor should know about them.

Make a list that details your personal health history, including major surgeries. Include family members and relatives who have had thyroid or autoimmune diseases.

Ask the office ahead of time if you need to fast for your blood work. This means that you can’t eat or drink after midnight the day of your appointment, with the exception of water.

Make a list of questions you want to ask your doctor. That way, you won’t forget anything during your appointment.

What to Expect Before and After Your Appointment

Before your appointment, you may need to fast or stop taking medications, but that’s only if your doctor directs you to do so.

Bring your lists of symptoms, current medications, and family history, and note any updates so your doctor can see. Be prepared to undergo blood work or possible thyroid scans.

After your appointment, follow your doctor’s orders and call the office for any clarifications. You may need to wait for the results of your blood work before making adjustments to your thyroid medication dose (if you’re on medication). Schedule all your follow-up appointments and referrals to specialists as necessary.

You may also ask your doctor about websites to follow or thyroid support networks you can check out for additional education and emotional support.

Prognosis of Hypothyroidism

The overall prognosis of hypothyroidism is promising, especially when caught early. This condition is treatable with thyroid hormones. But you will likely need to take medications for the rest of your life to help ensure that you get enough thyroid hormone.

Hypothyroidism can lead to numerous complications if it goes undetected and untreated.

Children with hypothyroidism can still hit normal growth and developmental milestones as long as they take their thyroid medications. Since children are still growing, they may need more frequent blood work than adults with hypothyroidism to help ensure they are getting the correct hormone replacement dosage.

Duration of Hypothyroidism

Hypothyroidism is often a chronic condition. As long as you stick with your treatment plan, though, you can lead a relatively normal life and reduce the risk for related health issues. That said, your medication may need to be adjusted from time to time, so it’s important to keep up with regular blood testing to make sure you’re getting the right amount.

Treatment and Medication Options for Hypothyroidism

There are a number of treatments for hypothyroidism, usually involving medication. Some people also use alternative medicines to help them manage their disease, too.

Common Medication for Hypothyroidism Treatment

Treatment for hypothyroidism generally involves taking the oral medicine levothyroxine, sold under the brand names Levothroid, Synthroid, and others.

Levothyroxine works by replacing thyroxine, the hormone your body can no longer make in adequate amounts. It’s typically taken daily to reverse symptoms of hypothyroidism.

“Studies after studies show levothyroxine is the best treatment of choice,” Dr. Endo explains. She notes that some people are allergic to the generic form of levothyroxine, mostly due to the color dye. In that case, you can use either the levothyroxine 50 microgram pills (these don’t have dye in them) or the brand Tirosint, although this is more expensive.

Levothyroxine may lower high cholesterol levels associated with hypothyroidism and may help you return to your baseline weight. The medicine causes very few serious side effects and is relatively inexpensive

Levothyroxine may lower your cholesterol levels and help you return to a normal weight. The medicine causes very few side effects and is relatively inexpensive.

The generic form of the drug is covered by most Medicare and insurance plans.

Treatment with levothyroxine is usually continued for the rest of your life, but your doctor may adjust your dose over time.

Why Figuring Out the Right Dosage of TSH May Take Some Time

TSH is just one marker that can indicate how your thyroid gland is functioning. Thyroid medications increase T4 hormones, which in turn reduce TSH back to normal ranges.

The process can take time to work, which is why doctors usually retest within six to eight weeks of a new thyroid medication prescription.

Once your TSH levels are consistent with your thyroid medication, your doctor may need to check your blood work only once or twice per year.

Factors That Can Affect the Proper Absorption of Levothyroxine

The absorption of levothyroxine, the most common prescription used to treat hypothyroidism, can be influenced by many foods and medications. It’s important to take levothyroxine in the morning with water, at least 30 minutes before eating.

You should avoid certain supplements and foods for several hours after taking levothyroxine. These supplements and foods include:

A Quick Warning About Subclinical Hypothyroidism and Ineffective Treatment

Subclinical hypothyroidism occurs when your TSH levels are elevated but the circulating thyroid hormone levels are normal. It is important for your doctor to determine how your TSH fluctuates before you begin your treatment regimen, as various health conditions can temporarily affect your thyroid levels. In most cases of subclinical hypothyroidism, you should have a discussion regarding the risks and benefits of treatment with levothyroxine with your doctor. That’s particularly true if your TSH is less than 10, which means your doctor should assess carefully whether to treat you for hypothyroidism.

Alternative and Complementary Therapies

Some people with hypothyroidism choose to supplement their treatment with alternative medicines, often to help with symptoms like fatigue, weight gain, stress, and mental fog.

Treatments can include yoga, meditation, hypnosis, supplements, or special diets.
Research that includes one small study of 20 women with hypothyroidism found that yoga helped patients manage their symptoms.

While people with thyroid disease are often careful to eat a diet low in iodine (which can worsen hypothyroidism once a patient has it) or to take vitamin D or calcium supplements, no diet or nutrient can cure thyroid disease.

Above all, keep in mind that any natural remedies for hypothyroidism are not regulated. In fact, some alternative treatments may be dangerous.

Hypothyroidism Treatments That Don’t Work

One treatment that medical doctors do not recommend? Natural dessicated thyroid products (either porcine or bovine products). The most common is the pig thyroid extract called Armour. Because the components of the pig’s thyroid hormone are very different from those of a human being, medical professionals recommend against using this agent, Endo says. These are most often prescribed by naturopathic doctors.

Learn More About Treatment for Hypothyroidism: Medication, Alternative and Complementary Therapies, and More

Hypothyroidism Diet

There’s no medical evidence that any particular diet will improve the functioning of your thyroid gland, despite anecdotal claims seen online and elsewhere.

If you’re taking thyroid hormone replacement for hypothyroidism, you may want to avoid consuming certain foods within a few hours of taking your thyroid medication. Some foods, like calcium, iron, and multivitamins, may block absorption of the thyroid hormone so should be taken four hours apart from levothyroxine, Endo says.

Foods to limit with hypothyroidism:

  • Soybean flour and cottonseed meal
  • Iron and calcium supplements
  • Antacids containing aluminum or magnesium
  • Some ulcer or cholesterol-lowering drugs
  • Walnuts

Overall, it is most important for people with hypothyroidism to eat a well-balanced diet, rather than consuming any particular food group, Endo says.

Learn More About What to Eat and Avoid if You Have Hypothyroidism

Prevention of Hypothyroidism

You can’t prevent hypothyroidism. While some risk factors may contribute to the development of this thyroid condition (including pituitary disorders, iodine deficiencies, congenital disease, and pregnancy), hypothyroidism is most often caused by factors out of your control.

Instead, it’s more important to be aware of the signs of hypothyroidism and to see your doctor if you suspect any of your symptoms could be related.

Complications of Hypothyroidism

Endo says some of the major risks of living with hypothyroidism include hypothermia, cognitive impairment, coronary artery disease, and hyperlipidemia (a high concentration of fat, or lipids, in the blood). In addition, she says that patients with hyperlipidemia and coronary artery disease should be especially aware of their hypothyroidism risk.

Other potential long-term complications include:

  • Decreased lung function

  • Depression due to slower mental functioning

  • An abnormal enlargement of the thyroid gland (goiter)

  • Heart issues, including high cholesterol and heart disease

  • Infertility in women, due to the inability to ovulate from lack of thyroid hormones

  • Inability to lose weight

  • Nerve damage in the arms, legs, and feet (peripheral neuropathy)

  • Delayed physical and intellectual development in babies born to mothers who are hypothyroid

  • Delayed development in children with untreated hypothyroidism

  • Myxedema coma (in rare cases), when the body’s level of thyroid hormone becomes extremely low

What Is Myxedema, or Advanced Hypothyroidism?

Myxedema is advanced hypothyroidism and occurs in patients who have had untreated and severe hypothyroidism for a long time.

The condition is rare — one estimate notes the number of cases in medical literature is only around 300 total — but it can be life-threatening. Myxedema is more common among older patients, particularly women, and research estimates that the mortality rate for this condition is between 20 and 50 percent.

Symptoms of myxedema include:

Research and Statistics: How Many People Have Hypothyroidism?

Hypothyroidism affects around 4.6 percent of people age 12 and older.

While anyone can develop hypothyroidism, this condition is most common in women and people over 60.

Also, an estimated 1 in 8 women will develop some form of thyroid disease, which can include hypothyroidism, hyperthyroidism, goiter, and thyroid cancer, among others.

Related Conditions and Causes of Hypothyroidism

Underactive thyroid may also be due to these causes:

Medication Many types of medication can affect the thyroid gland. Lithium is a common drug that can cause hypothyroidism.

Radioactive iodine, which is used to treat hyperthyroidism (overactive thyroid), may also impair your thyroid function.

In addition, many other drugs can affect your thyroid gland, such as amiodarone, any chemotherapy category with tyrosine kinase inhibitor and checkpoint inhibitors, steroids, interferon alpha, and more, Endo says. Check with your doctor if you are concerned about any medication you are taking.

Radiation Therapy Radiation for cancers of the head and neck can lead to hypothyroidism.

Congenital Problems Sometimes babies are born without a thyroid gland or with a deformed gland, which results in reduced thyroid function.

Rare Disorders Diseases that deposit abnormal substances in the thyroid can affect its ability to function. These diseases may include amyloidosis (a rare disease in which amyloid proteins build up in organs like the heart and kidneys), sarcoidosis (a disease that involves the growth of inflammatory cells in the body), or hemochromatosis (the buildup of too much iron in the body).

Pregnancy About 15 percent of pregnant women may experience an increase in the size of their thyroid during pregnancy; it returns to normal after birth. This can be a normal process to increase thyroid hormone production needed to support the pregnancy.

The same antibodies that cause Hashimoto’s thyroiditis can be present in women who become pregnant. In the year following the pregnancy, women with these antibodies can have thyroid dysfunction, either hyperthyroidism or hypothyroidism.

Pituitary Disorder When the pituitary gland fails to produce enough TSH, hypothyroidism can occur.

Usually this is caused by a tumor in the pituitary.

Such tumors typically occur in older adults, and about 10,000 pituitary tumors are diagnosed each year in the United States.

Aging Well With Hypothyroidism

In patients older than 60, hypothyroidism becomes very common and increases with age. In fact, up to 1 in 4 patients in nursing homes may have undiagnosed hypothyroidism.

Symptoms may include:

Since symptoms may mimic normal aging, it’s important for a doctor to make an assessment and decide on a possible course of treatment, such as thyroid hormone replacement.

Doses of hormone treatment must be increased slowly, to prevent too much stress on other body systems, like the heart and central nervous system.

Surprisingly, some studies have found that slightly elevated TSH levels could contribute to an extended life span.

Having a slightly higher TSH with a normal T4 level is called subclinical hypothyroidism. People over age 65 with hypothyroidism should be treated, but they should also discuss the TSH treatment goal (a higher normal TSH goal may be better). Still, hypothyroidism in older adults should be treated, primarily to relieve symptoms and prevent myxedema.

Resources We Love

Favorite Orgs for Essential Thyroid Disease Info

American Thyroid Association

Founded nearly a century ago, the American Thyroid Association is one of the most trusted and well-known thyroid organizations; it provides the latest information on diseases that affect the thyroid gland. On its website, you will find a variety of thyroid-related brochures, updated treatment guidelines, and more. If you’re looking for the latest information on hypothyroidism research and treatment, be sure to sign up for the Friends of the ATA newsletter, which is delivered via email.

Hormone Health Network

This is another one of our favorite patient-centered websites for hypothyroidism, thanks to its vast library of in-depth information pertaining to the causes and symptoms of this condition. Because hypothyroidism is a hormone-related condition, you can also learn more about other aspects of endocrinology that could affect your thyroid. Be sure to check out the pages on pregnancy, goiter, stress, and more.

National Institute of Diabetes and Digestive and Kidney Diseases

A branch of the National Institutes of Health, the NIDDK is a leader in research pertaining to all kinds of endocrine diseases, including hypothyroidism. Be sure to review and bookmark the NIDDK’s webpage on hypothyroidism as you prepare for your first appointment with your endocrinologist. Check out the list of risk factors and causes to have on hand as you discuss diagnosis and treatment options with your doctor.

American Association of Clinical Endocrinologists

This website isn’t for doctors only. Enter the Public Community Portal’s thyroid page for professional knowledge related to hypothyroidism treatment guidelines and other related conditions, such as thyroid nodules, to better prepare yourself for your appointment with an endocrinologist. While you’re there, you can also learn how to check your own thyroid gland in this step-by-step guide.

Favorite Alternative Medicine Resource

National Center for Complementary and Integrative Health

Depression, stress, and fatigue are some of the many symptoms you might experience with hypothyroidism. Alongside any medical treatment, you may be tempted to research yoga and other complementary practices for support. Before you do, talk to your doctor and come armed with information from this resource. We like the NCCIH because it provides straightforward and up-to-date research on alternative medicine.

Favorite Online Support Network

Thyroid Federation International

Looking for a local or online support group? We like Thyroid Federation International because of its ability to help patients connect with one another across global borders. Wherever you’re located, finding a support group near you is simple via this list of member organizations.

Favorite Resources for Diet Advice

Thyroid Dietitian

While no specific diet can cure hypothyroidism, eating well can help you feel your best. Still, it can be difficult knowing which foods to eat and avoid, as well as how to cook thyroid-healthy meals. If you need help getting started, check out some of the resources offered by registered dietitian Nicole Morgan, including her YouTube channel featuring free cooking and exercise tips, as well as recommendations for thyroid diet books, grocery shopping must-haves, and beauty products. Be sure to discuss these diet and exercise tips with your doctor before getting started.

Additional reporting by Stephanie Bucklin and Lynn Marks.

Editorial Sources and Fact-Checking

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