Conditions InDepth: Hyperthyroidism

Hyperthyroidism is too much thyroid hormone in the blood. The thyroid gland is in the front of the neck. It makes two hormones that control metabolism, such as:

  • How many calories you burn
  • How warm you feel
  • How much you weigh
  • How the body handles things that the heart, gastrointestinal, and nervous system do

The Thyroid Gland

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Graves disease is the most common. It causes the immune system to make antibodies that cause the thyroid gland to make too much hormone.

Hyperthyroidism can also be from:

  • Swelling of the thyroid
  • A nodule on the thyroid
  • Taking too much thyroid replacement
  • Substances made by tumors of the thyroid gland, testes, or ovaries
  • Consuming too much iodine (rare)

Treating hyperthyroidism can lead to hypothyroidism. This is when the gland does not make enough hormone.

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References:

Bahn RS, Burch HB, Cooper DS, et al. Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Endocr Pract. 2011 May-Jun;17(3):456-520, also published in Thyroid 2011 Jun;21(6):593.
Hyperthyroidism (thyrotoxicosis). Merck Manual Professional Version website. Available at:
...(Click grey area to select URL)
Accessed May 17, 2019.
Hyperthyroidism and other causes of thyrotoxicosis. EBSCO DynaMed website. Available at: https://www.dyname... . Updated November 1, 2018. Accessed May 17, 2019.
Primary hyperthyroidism. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at:
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Updated March 2019. Accessed May 17, 2019.
Thyroid disorders. Healthy Women website—National Women's Health Resource Center website. Available at:
...(Click grey area to select URL)
Accessed May 17, 2019.
Last reviewed March 2019 by EBSCO Medical Review BoardJames P. Cornell, MD
Last Updated: 5/20/2019

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