Hypothyroidism is a kind of Thyroid disease. If you have hypothyroidism that means you have an underactive thyroid ("hypo-" means "under" or "below normal"). In people with hypothyroidism, the thyroid does not make enough thyroid hormone to keep the body running normally. Common causes of hypothyroidism are autoimmune disease, surgical removal of the thyroid, and radiation treatment.
The thyroid is a butterfly-shaped endocrine gland usually located in the lower front of the neck below the larynx (the voice box).
