Underactive Thyroid Information

When your thyroid does not make enough thyroid hormones to meet your body's needs, you are said to have an underactive thyroid. This condition affects about 5 percent of the U.S. population, and it is much more common in older adults and women. It has many possible causes, such as surgery, illness, or radiation treatment.
Without enough thyroid hormone, many of the body's functions slow down. Symptoms vary from person to person, but can include things like:
  • Fatigue
  • Weight gain
  • Intolerance to cold.
Treatment typically involves taking thyroid replacement medication to return hormone levels to normal.
(For more information on this condition, including how it is diagnosed, click Underactive Thyroid.)
Last reviewed by: Arthur Schoenstadt, MD