Thyroid gland location
Thyroid gland location

What is the thyroid?

The thyroid is a butterfly-shaped gland in the lower front part of the neck. Glands are organs located in different parts of the body. Glands make and release hormones, substances that aid body function and growth. The thyroid gland helps regulate your body temperature and control your heart rate and metabolism (the process that turns the food you eat into energy).

What is hyperthyroidism?

Hyperthyroidism is an overactivity of the thyroid. This means that your thyroid produces and releases more hormones than your body needs. This can affect your body and the way it functions.

Who is affected by hyperthyroidism?

Both men and women can have hyperthyroidism, but it occurs most often in women aged 20 to 40.

What are the causes of hyperthyroidism?

There are several causes of hyperthyroidism:

  • Graves’ disease: This is a disorder in which the immune system attacks the thyroid, causing it to make too much thyroid hormone. Graves disease is a hereditary condition (affects several members of the family) and more commonly occurs in women than in men. Graves’ disease is the most common form of hyperthyroidism and accounts for 85 percent of cases.
  • Thyroid nodules: A thyroid nodule is a lump or growth of cells (which may be cancerous or non-cancerous) in the thyroid gland that can cause it to produce more hormones than your body needs.
  • Thyroiditis: This is a general term that refers to an inflammation (swelling) of the thyroid caused by an infection or a problem with the immune system. It causes the thyroid gland to leak hormones, resulting in more than your body needs. This condition can occur after the delivery of a baby (postpartum thyroiditis) or from taking the drugs interferon and amiodarone.

What are the symptoms of hyperthyroidism?

Symptoms of hyperthyroidism can include the following:

  • Rapid heartbeat
  • Feeling shaky, nervous
  • Weight loss
  • Increased appetite
  • Diarrhea
  • Double vision
  • Thin skin
  • Menstrual changes
  • Intolerance to heat and excessive sweating
  • Swelling and enlargement of the neck from an enlarged thyroid gland (goiter)
  • Bulging of the eyes (seen with Graves’ disease)
  • Muscle weakness

Last reviewed by a Cleveland Clinic medical professional on 01/18/2019.


  • National Institute of Diabetes and Digestive and Kidney Diseases. Hyperthyroidism. Accessed 1/22/2019.
  • American Thyroid Association. Hyperthyroidism. Accessed 1/22/2019.
  • Merck Manuals Consumer Version. Hyperthyroidism. Accessed 1/22/2019.

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