Hypothyroidism (underactive thyroid) is a condition in which the thyroid gland doesn’t produce enough of certain important hormones, either because of a production deficiency or because of a resistance to its action in the tissues that produce the function.
The thyroid gland is an important organ of the endocrine system. It is located at the front of the neck, just above where the collarbones meet. The thyroid makes hormones that control the way every cell in the body uses energy. This process is called metabolism.
Hypothyroidism can be congenital or acquired, the latter being more common in women and persons over the age of 50.