Everything You Need to Know About the Thyroid

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The thyroid is a small, butterfly-shaped gland located at the front of the neck, below the Adam's apple. The thyroid gland is a key part of many of your body's functions, producing and releasing hormones that help regulate your body's metabolism, temperature, growth, and development.

Sometimes, a disease, growth, or other condition affects your thyroid. When this happens, you may experience a host of symptoms since your thyroid is unable to normally regulate your body's functions.

What Does Your Thyroid Do?

Your thyroid releases different hormones into the blood that help in controlling major body functions. The three main hormones thyroid gland produces are:

  • Triiodothyronine, also known as T3
  • Tetraiodothyronine, also called thyroxine or T4
  • Calcitonin

T3 and T4 play an important role in regulating the body's metabolism, which refers to all the bodily processes that convert or use energy. The two hormones make the body's cells work harder so that the cells need more energy. In increasing your metabolism in this way, T3 and T4 help regulate things like body temperature, heartbeat, concentration, and food-to-energy conversion. For children, the two hormones can help with growth and brain maturation.

Calcitonin, the third hormone the thyroid produces, helps regulate how your body uses calcium.

The thyroid gland should releases just enough of each hormone so that all the bodily functions continue normally. A different gland, the pituitary gland, that sits at the base of the brain controls how much hormone the thyroid releases. Overproduction or underproduction of thyroid hormone can lead to a variety of symptoms, including effects on your mood and digestion, that can disturb your daily life.

What Are the Signs of Thyroid Problems?

The thyroid usually releases a steady amount of hormones into the blood. Sometimes there might be a problem where not enough or too much hormone is being produced. You also can't typically see or feel your thyroid. Sometimes your thyroid can grow to be too big or have a growth on it where you can see or feel it through your neck.

If there is any sort of problem with your thyroid, you might experience:

  • Weight changes
  • Intolerance to heat or cold
  • A change in how much you sweat
  • Heavier, lighter, or fewer periods
  • Muscle weakness
  • Constipation or diarrhea
  • A lower or faster heart rate
  • Feelings of irritability, sadness, or nervousness
  • Swelling in your neck
  • Problems swallowing or breathing

Types of Thyroid Problems

Thyroid disease and conditions make it so that there is an imbalance in the amount of hormone needed by the body, whether there is too much hormone or there is too little to carry out body functions normally.


Hyperthyroidism, or overactive thyroid, is when the thyroid produces too much hormone.

Too much hormone in your bloodstream can accelerate various body functions. For example, you may lose weight despite eating more, sweat more, and have a faster heartbeat.

The most common cause of hyperthyroidism is Graves' disease, which is a condition in which our immune system attacks our own thyroid cells. Other causes of hyperthyroidism include:

  • Thyroid nodules: These growths on your thyroid are usually non-cancerous and are more common in older adults.
  • Thyroiditis: This is inflammation of the thyroid gland.
  • High levels of iodine: Iodine is in some medicines, cough syrups, seaweed, and seaweed-based supplements.

While hyperthyroidism can occur in anyone, it is more common in women and people older than 60. Other things that put you at higher risk of developing hyperthyroidism are:

  • Being pregnant or having had a baby within the past six months
  • Having a family history of thyroid disease
  • Having had thyroid surgery
  • Having type 1 diabetes
  • Having pernicious anemia, when the body can't make enough healthy red blood cells because it can't properly absorb vitamin B12
  • Having another autoimmune disease

Treatment for hyperthyroidism can include medication, radioiodine therapy (swallowing pills or capsules with radioactive iodine), and thyroid surgery. Your healthcare provider will determine which is best for you.


Hypothyroidism, or underactive thyroid, is when the thyroid doesn't make enough hormones.

Without enough thyroid hormone, many of your body functions may slow down. You may gain weight, be fatigued, and have thinning hair.

Some people are born with hypothyroidism. The most common cause of hypothyroidism is Hashimoto's disease, an autoimmune condition in which your immune cells destroy the thyroid gland. Other causes of hypothyroidism include:

  • Thyroiditis
  • Surgery to remove part of the or the entire thyroid
  • Radiation treatment to the thyroid

Hypothyroidism is more common among women and those older than 60. Other risk factors include having a personal or family history of a thyroid problem. The following conditions could also put you at risk for hypothyroidism:

  • Turner syndrome, a genetic, chromosomal disorder that affects females
  • Sjogren's syndrome, an immune disorder that causes dry eyes and mouth
  • Pernicious anemia
  • Type 1 diabetes
  • Rheumatoid arthritis
  • Lupus

Hypothyroidism is treated through medication. Symptoms can sometimes be improved by changes in diet and lifestyle as well.


Thyroiditis is inflammation, or swelling, of the thyroid gland. Your thyroid may continue to function normally, or you may develop hyperthyroidism or hypothyroidism. Thus, people with thyroiditis can have a variety of symptoms depending on how the inflammation is affecting their thyroid hormones.

Radiation, trauma, or infection can cause thyroiditis. In these cases, the condition is usually painful. You might have neck pain or discomfort, and your thyroid may feel tender when touched.

De Quervains thyroiditis is the most common cause of neck pain stemming from the thyroid. This type of thyroiditis is associated with viral infections like mumps, measles, influenza, and COVID-19.

When an autoimmune disease or medication is causing thyroiditis, there is usually no pain.

One type of pain-free thyroiditis is postpartum thyroiditis. About 10% of women are estimated to experience thyroid inflammation after giving birth. Because postpartum thyroiditis symptoms like tiredness and mood changes might be attributed to baby blues, the condition often goes undiagnosed.

Thyroiditis often goes away on its own, such is usually the case with postpartum thyroiditis, when the thyroid returns to normal within 12 to 18 months. If you have pain, you can take anti-inflammatories. If your thyroiditis is causing an overproduction or underproduction of thyroid hormone, you might also need treatment to normalize those levels.

Thyroid Nodules

Any lumps or bumps in the thyroid gland are called thyroid nodules. A thyroid nodule can be solid or filled with fluid. Nodules are usually benign (not cancerous). They may become overactive and cause an increase in thyroid hormone levels in the blood.

Mostly, thyroid nodules do not cause any signs and symptoms. But as they increase in size, the nodule can cause difficulty in swallowing and breathing. If they get big enough, nodules can be seen or felt. This is uncommon, though, with fewer than 10% of people having thyroid nodules that a healthcare provider can feel. Usually, nodules can only be seen with an ultrasound.

While someone of any age can develop nodules, the growths are more common among older adults.

If it's not growing or causing any symptoms, a non-cancerous nodule might be left alone and monitored.

Thyroid Cancer

Thyroid cancer is a type of cancer that develops in your thyroid gland. The cancer develops when the thyroid cells start to multiply more than they should.

About two or three out of every 20 thyroid nodules are cancerous.

The cancerous growth doesn't usually cause symptoms. Sometimes, you may have a hoarse voice or a lump or swelling in your neck. If the lump gets big enough, you may have trouble swallowing and breathing.

Women, especially those aged 25 to 65, are more likely to get thyroid cancer. Women who have the following are at particularly higher risk:

  • Radiation therapy to the head or neck to treat cancer (especially as a child)
  • A history of goiter
  • A family history of thyroid cancer

Usually, thyroid cancer is treated by removing the thyroid. If needed, radioiodine therapy can be used after surgery to destroy any remaining thyroid cancer cells.


A goiter is an unusually large thyroid gland. It can cause neck swelling. If a goiter gets big enough, you can see and feel it. A particularly large goiter can also cause:

  • A feeling of throat tightness
  • Coughing
  • Problems swallowing or breathing

Other thyroid conditions like nodules, thyroiditis, Hashimoto's disease, and Graves' disease can a goiter. Women who have not yet reached menopause are most likely to have goiter.

How Are Thyroid Problems Diagnosed?

Your healthcare provider may use the following tools to figure out if you have a thyroid issue and, if so, what the issue is:

  • Medical history including your family history of thyroid disease.
  • Physical examination
  • Blood tests such as T3, T4, thyroid stimulating hormone (TSH), and thyroid antibody levels to check your thyroid function
  • Imaging tests such as thyroid scans and ultrasounds
  • A radioactive iodine uptake test (You will take radioactive iodine, and the healthcare provider will measure how much iodine the thyroid gland takes up.)
  • Biopsy (to see if a growth is cancerous)

A healthcare provider will usually start with blood tests and then order additional tests, like imaging tests, if needed.

A Quick Review

The thyroid is a small, butterfly-shaped gland that releases different hormones. The hormones help control many different body functions. The major role of thyroid hormone is to regulate the body's metabolism; it also has an important role in growth and development. If there is a problem with your thyroid, it can release too many or not enough hormones. If your thyroid levels are out of whack, you can experience a variety of symptoms that can affect your daily life. Therefore, it's crucial to keep your thyroid health in check and see a healthcare provider if you experience any symptoms of thyroid dysfunction.

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10 Sources
Health.com 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.
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