The thyroid listens to signals from another gland that is found in our brain, called the pituitary gland, which is controlled by the hypothalamus. The hypothalamus is responsible for helping to control internal body functions such as body temperature, salt and water balance, and sex drive. The hypothalamus also influences the pituitary gland, and in turn, the thyroid. When thyroid hormone levels are low, the hypothalamus sends TSH Releasing Hormone (TRH), to the pituitary gland. The pituitary gland receives this message and produces Thyroid Stimulating Hormones (TSH) that stimulate the thyroid to produce more T3 and T4.
This process, of course, is assuming that the thyroid, pituitary gland, and hypothalamus are healthy and functioning properly. When one of these glands’ functions are compromised for any number of reasons, a variety of health concerns – both physical and mental, could arise.