What is a cold thyroid?

Hypothyroidism, often simply called underactive thyroid, is a common condition in which the thyroid gland doesn't produce enough thyroid hormone. In children, insufficient thyroid hormone production can lead to mental retardation, short stature, and skeletal muscle weakness and poor muscle tone (hypotonia) in addition to the signs and symptoms common to people of all ages.

Cold thyroid typically refers to the sensation of a cool or cold skin to the touch, that may accompany hypothyroidism but it's more likely to signify other conditions such as poor body temperature regulation with aging, certain health issues or nutritional/lifestyle factors than an underlying thyroid malfunction.