Hypothyroidism (Underactive Thyroid) | NIDDK

On this page: What is hypothyroidism? Hypothyroidism, also called underactive thyroid, is when the thyroid gland doesn’t make enough thyroid hormones to meet your body’s needs. The thyroid is a small, butterfly-shaped gland in the front of your neck. Thyroid hormones control the way the body uses energy, so they affect nearly every organ in … Read more