'Your doctor says you don’t need treatment, but could he or she be wrong?
Thyroid-stimulating hormone (TSH) is secreted by cells in the front part of the pituitary gland. This tiny area in the brain regulates the key endocrine function of the thyroid gland by stimulating production of thyroxin, the main thyroid hormone.
TSH is the main hormone tested by your doctor to determine if your thyroid gland is functioning properly. Too much TSH means the pituitary gland is trying to get a sluggish thyroid gland to work better. Too little means there is enough thyroxin in your body so TSH remains low until more is needed.
If the TSH is too high you have a condition called hypothyroidism, or an under-functioning thyroid gland. If it’s extremely low, you have an overactive thyroid gland, or hyperthyroidism.'