Thyroid appearing in a woman's neck

Hyperthyroidism

Also known as an overactive thyroid gland

Hyperthyroidism is a disease that occurs when your thyroid gland—a small, butterfly-shaped gland located in your neck—produces too much thyroid hormone.

Graves’ disease is the most common cause, affecting over 70% of people with hyperthyroidism. In Graves’ disease, a person’s immune system inappropriately produces antibodies that overstimulate the thyroid gland, causing excessive thyroid hormone production. 

Hyperthyroidism can increase metabolism, leading to weight loss, frequent bowel movements, sweating, a fast heart rate, and more. Blood tests diagnose it, and treatment typically involves taking prescription medication or undergoing radioactive iodine ablation. Less commonly, surgical removal of the thyroid gland may be performed.

Frequently Asked Questions

  • What causes hyperthyroidism?

    The main cause of hyperthyroidism in the U.S. is an autoimmune disease called Graves' disease. In this disease, antibodies attack the thyroid gland causing it to enlarge and produce excess thyroid hormone. Other causes of hyperthyroidism include toxic multinodular goiter, thyroiditis, taking supplements that contain high amounts of iodine or animal thyroid tissue, and taking too much thyroid hormone.

  • How to treat hyperthyroidism?

    Hyperthyroidism is treated with prescription medication, radioactive iodine therapy, or surgery. The treatment chosen depends on factors like the cause behind the hyperthyroidism, the severity of the disease, the presence of thyroid eye disease, and the patient’s age and overall health.

  • What are the symptoms of hyperthyroidism?

    Hyperthyroidism causes your body's metabolism to accelerate. This leads to a variety of symptoms such as tachycardia, weight loss, anxiety and irritability, tremor (especially of the hands), insomnia, sweating, and frequent bowel movements. If hyperthyroidism is uncontrolled or untreated, a heart arrhythmia called atrial fibrillation and bone loss (osteoporosis) may develop.

  • Is hyperthyroidism curable?

    Unfortunately, the answer is not so straightforward. While radioactive iodine and surgery can permanently cure hyperthyroidism caused by Graves' disease, a person will still need to take lifelong hormone replacement. Likewise, certain types of thyroiditis that may cause a hyperthyroid phase (e.g., postpartum thyroiditis) are not necessarily cured, as they may recur after future pregnancies.

Key Terms

Thyroid storm
Act Fast If You Have Symptoms of This Life-Threatening Condition
Woman getting eye exam
Learn How Graves' Disease Can Affect the Eyes
Woman being examined by a doctor
An Overview of Graves' Disease
Page 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.
  1. Manandhar K, Risal A, Steiner TJ, Holen A, Linde M. The prevalence of primary headache disorders in Nepal: a nationwide population-based study. J Headache Pain. 2015;16:95. doi:10.1186/s10194-015-0580-y

  2. Kravets I. Hyperthyroidism: Diagnosis and Treatment. Am Fam Physician. 2016;93(5):363-70.

  3. Burch H, Cooper D. Management of Graves Disease. JAMA. 2015;314(23):2544. doi:10.1001/jama.2015.16535

Additional Reading