The NHS defines an underactive thyroid (or hypothyroidism) as a failure of the thyroid gland, located in the neck in front of the windpipe, to produce sufficient quantities of the hormones needed to regulate the body’s metabolism, such as triiodothyronine and thyroxine.
Without the right level of these hormones in production to moderate how the body stores and uses energy, many of its functions can gradually begin to slow down, affecting the internal organs.
