In teens who have hyperthyroidism, the thyroid gland makes and releases too much thyroid hormone. The body’s functions speed up, and this causes a range of symptoms.

An overactive thyroid, or hyperthyroidism, means that the gland produces an excess of thyroid hormones and releases them into the bloodstream. These hormones help regulate growth and metabolism.

Graves’ disease is the most common cause of hyperthyroidism in teenagers. Graves’ disease is an autoimmune condition, which means it is the result of an atypical immune system response.

Hyperthyroidism can lead to potentially life threatening or life changing symptoms in teens, including a rapid heart rate and early puberty.

Keep reading to learn more about hyperthyroidism in teens, including what causes it and how caregivers can support teens with this condition.

teenager holding skateboardShare on Pinterest
Marco Govel/Stocksy

The thyroid is a small, butterfly-shaped gland that sits at the front of the neck. In a person with hyperthyroidism, the gland makes too much thyroid hormone and releases it into the bloodstream.

Thyroid hormones regulate the way the body uses energy, and they can affect every organ in the body. An excess of thyroid hormones in the blood may cause the body’s functions to speed up. This can affect functions such as digestion and heartbeat.

According to the American Thyroid Association (ATA), teenagers with hyperthyroidism may experience symptoms such as:

  • anxiety and nervousness
  • lack of concentration
  • declines in school or work performance
  • mood changes and irritability
  • constant warmth
  • palpitations (racing heart)
  • tremors (shakiness in the hands)
  • increased frequency of bowel movements
  • weight loss despite typical or increased hunger
  • sleep problems
  • tiredness
  • reduced strength and reduced ability to exercise

In some teens, the thyroid gland can become enlarged and create swelling in the neck. Doctors call this a goiter.

Teens can develop hyperthyroidism for a variety of reasons.

Graves’ disease

Graves’ disease is the main cause of hyperthyroidism in teenagers.

The ATA states that in 95% of children with the condition, the cause is Graves’ disease.

Graves’ disease is an autoimmune condition, which means that antibodies in the immune system attach to certain receptors on cells of the thyroid gland, causing it to produce excess thyroid hormone.

In fewer than 25% of cases, Graves’ disease goes away without treatment.

Learn more about Graves’ disease.

Toxic nodular goiter

Toxic nodular goiter may also cause hyperthyroidism in teens.

A person with this condition can develop one (single nodular) or more (multinodular) benign growths that directly or indirectly affect the thyroid. As a result, the gland releases an excess of thyroid hormone into the blood.

However, this condition is rare in teens. It is more common in older adults.

Learn more about multinodular goiters.


Thyroiditis, or inflammation of the thyroid gland, can cause hyperthyroidism. However, this is rare and usually occurs in the early stages of the disease.

A teen may develop this condition after trauma to the thyroid gland or infection. The thyroid typically heals from this type of hyperthyroidism after a few months.

However, Hashimoto’s thyroiditis can sometimes cause lasting thyroid damage, which stops the gland from working properly and almost always leads to hypothyroidism, or underactive thyroid.

Learn more about Hashimoto’s thyroiditis.

Other causes

Rarer but possible causes include:

  • Certain medications: for example, a heart medication called amiodarone
  • Genetics: a change in the thyroid-stimulating hormone (TSH) receptor gene that switches it on permanently
  • Growths: a tumor that causes the pituitary gland to make too much TSH

A teenager may be more likely to develop Graves’ disease and hyperthyroidism if they have:

Graves’ disease occurs 3–4 times more often in teenage girls than in boys.

Teenagers who have pernicious anemia also have an increased risk of developing hyperthyroidism. Pernicious anemia results from vitamin B12 deficiency, which can prevent the body from making enough healthy red blood cells. A teenager who does not eat animal products — such as milk, eggs, or meat — and does not take vitamin B12 supplements may develop this condition.

Stress may be another risk factor for hyperthyroidism. Some people with Graves’ disease experience major stress in their life about a year before receiving a diagnosis.

People who smoke are more likely to have Graves’ disease. They are also at greater risk of developing an eye disease that has an association with poor thyroid function. It may cause symptoms such as inflammation, swelling, and bulging of the eye.

To diagnose a teenager with hyperthyroidism, a doctor looks at their clinical symptoms and orders blood tests. A person with hyperthyroidism will have low levels of TSH and high levels of the thyroid hormones triiodothyronine (T3) and thyroxine (T4).

Doctors may perform further tests on teens, such as:

  • Antibody test: to measure TSH receptor antibody levels
  • Ultrasound: to assess the structure of the thyroid gland and blood flow
  • Radioactive iodine uptake test: to measure the amount of radioactive iodine the thyroid takes up over a certain time period

Around one-third of people with Graves’ disease develop thyroid eye disease. The presence of these eye problems or a goiter can help a doctor determine whether a teenager has Graves’ disease specifically.

Learn more about the complications of Graves’ disease.

Most people with thyroid conditions need lifelong treatment. Treatment for hyperthyroidism aims to regulate levels of T3 and T4 and eliminate the signs and symptoms of the disease.


Antithyroid medications can stop the thyroid from making new thyroid hormone.

Methimazole (Tapazole) is the only antithyroid medication approved for use in children and teenagers in the United States. Antithyroid medications typically help normalize a person’s thyroid hormone levels. However, the course of treatment may take several years.

Sometimes, doctors may prescribe beta-blockers alongside antithyroid medications to help slow down a person’s heart while they wait for their levels of T3 and T4 to normalize.

If antithyroid medication does not work or causes side effects, a person has two options that permanently stop the thyroid from working: surgery and radioactive iodine therapy. These may cause hypothyroidism. However, doctors consider hypothyroidism more stable and manageable than hyperthyroidism.


A surgeon can perform a thyroidectomy — removal of the thyroid gland — to treat hyperthyroidism if Graves’ disease is the cause.

Doctors may recommend this treatment method for teens who:

  • have a goiter or thyroid nodule
  • have hyperthyroidism that is not manageable
  • need a rapid cure

Surgery complications are rare but may include damage to the parathyroid glands or the nerves that control the vocal cords.

Radioactive iodine treatment

Thyroid cells can absorb iodine, and giving a person a small dose of radioactive iodine can destroy these cells. Radioactive iodine treatment involves taking one capsule and takes effect within weeks to months.

The treatment is safe and effective — radioactive iodine has a cure rate of 95%. However, doctors do not recommend it for teens who have:

After surgery or radioactive iodine treatment, the teen will have permanent hypothyroidism and will always need to take thyroid hormone medication.

The developing bodies of children and teenagers need thyroid hormone for typical growth and development. Like those of adults, teens’ bodies need adequate levels of these hormones to maintain certain functions.

Hyperthyroidism can speed up many of the body’s processes and functions, including puberty.

If excess thyroid hormone circulates in a teenager’s blood for a long time, it can speed up their growth and cause puberty to occur earlier. This may have negative effects — for example, a teenager may not grow as tall as they otherwise would have.

Diagnosis and treatment of hyperthyroidism can be stressful. It may take a long time to find the right dose of medication for teenagers with this condition.

Healthcare professionals can advise on support groups for teenagers with hyperthyroidism and their caregivers.

Hyperthyroidism can affect school performance, so caregivers may want to discuss the teen’s condition with the school. Changes to the teen’s learning plan may provide the support they need to maintain their performance in school.

Also, caregivers may need to monitor teenagers who have this condition. Caregivers should be aware of any indications that a teenager’s condition may be worsening.

A caregiver can contact a doctor if they have concerns or questions about hyperthyroidism.

In teens with hyperthyroidism, the thyroid makes too much thyroid hormone and releases it into the bloodstream. This can cause various symptoms, including irritability, anxiety, palpitations, and more frequent bowel movements.

A family history of autoimmune conditions increases a person’s risk. Graves’ disease is the main cause of hyperthyroidism in teens.

Measuring the levels of thyroid-related hormones — T3, T4, and TSH — can help doctors diagnose the condition. Typically, TSH levels are low in people with this condition, while T3 and T4 are high. Treatment for hyperthyroidism in teens may involve surgery or antithyroid medication.