The thyroid gland makes a hormone (thyroid hormone) that helps control your heart rate, body temperature, and energy level. A gland in your brain (pituitary gland) constantly monitors the amount of thyroid hormone in your blood.
If you do not have enough thyroid hormone, your pituitary releases extra thyroid-stimulating hormone (TSH), which tells your thyroid to absorb iodine from the blood and use it to make more thyroid hormone. Your thyroid gland then makes and releases the hormone directly into your bloodstream. Your pituitary gland senses that the right amount of thyroid hormone is moving through your body, so it slows its production of TSH back to normal.
After you have any kind of thyroid surgery, your body will no longer be able to make the thyroid hormone it needs. You will therefore need to take thyroid hormone replacement pills to give your body the natural thyroid hormone it can no longer make on its own.
If you have follicular or papillary cancer, the thyroid hormone pills can also slow down the growth of any cancer cells that are left in your body.
The generic name of the hormone is levothyroxine sodium. It is sold as Synthroid®, Levoxyl®, Levothroid®, Unithroid®, and other brand names.
This content has been reviewed and approved by Myo Thant, MD.