The thyroid gland is crucial to normal body function. Its main functions are control of cellular metabolism ; maintenance of normal brain /neurological function; supporting the pumping effect of the heart; normal remodelling of bone. It also affects menstrual cycles and fertility; mood and cognitive function; and has a role in the activation of all other hormones.

Hypothyroidism (underactive thyroid) is common in midlife, especially in women; see below for diagnosis and treatment.

Symptoms of Hypothyroidism
Causes of hypothyroidism
Testing for thyroid hormone
Functional Hypothyroidism
Treating Hypothyroidism