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.

What are the risk factors for hyperthyroidism?What are the symptoms of hyperthyroidism?How is hyperthyroidism diagnosed?What are the treatments for hyperthyroidism?Are there screening tests for hyperthyroidism?How can I reduce my risk of hyperthyroidism?What questions should I ask my doctor?Where can I get more information about hyperthyroidism?

Revision Information

  • Reviewer: EBSCO Medical Review BoardJames P. Cornell, MD
  • Review Date: 03/2019 -
  • Update Date: 05/20/2019 -