Your thyroid gland produces two main hormones — thyroxine (T-4) and triiodothyronine (T-3).
These hormones circulate in your bloodstream and help regulate your metabolism. They maintain the rate at which your body uses fats and carbohydrates, help control your body temperature, influence your heart rate, and help regulate the production of proteins. Your thyroid gland also produces calcitonin — a hormone that helps regulate the amount of calcium in your blood.