Hyperthyroidism Symptoms

Signs and symptoms caused by excessive amounts of thyroid hormones

When you have hyperthyroidism, your body is producing excessive amounts of the thyroid hormones T3 and T4. Since these hormones regulate your metabolism (how your body processes and uses energy), having too high a level will cause symptoms related to a high metabolism. In essence, hyperthyroidism speeds up some of your body's processes.

However, not everyone with hyperthyroidism will experience all of the symptoms listed below. These are all the possible symptoms, but symptoms vary based on how long your thyroid gland has been producing too much T3 and T4, how much extra T3 and T4 you have, and your age.

Here's what you may experience with hyperthyroidism:

  • Appetite change (decrease or increase)
  • Difficulty sleeping (insomnia)
  • Fatigue
  • Frequent bowel movement—perhaps diarrhea
  • Heart palpitations
  • Heat intolerance
  • Increased sweating
  • Irritability
  • Light menstrual periods—perhaps even missed periods
  • Mental disturbances
  • Muscle weakness
  • Nervousness
  • Problems with fertility
  • Shortness of breath
  • Sudden paralysis
  • Tremor/shakiness
  • Vision changes
  • Weight loss-but perhaps weight gain
  • Dizziness
  • Thinning of hair
  • Itching and hives
  • Possible increase in blood sugar

If Graves' disease is the underlying cause of your hyperthyroidism, there are some additional symptoms associated with that. Please read our article on Graves' disease symptoms to learn more about those.

View Sources
  • AACE Thyroid Task Force. American Association of Clinical Endocrinologists Medical Guidelines for Clinical Practice for the Evaluation and Treatment Of Hyperthyroidism and Hypothyroidism. Endocr Pract. 2002;8(6):457-469.
  • Skugor, M. The Overactive Thyroid:  Hyperthyroidism. In: The Cleveland Clinic Guide to Thyroid Disorders. New York: Kaplan Publishing; 2009:49-67.