The thyroid gland is an important endocrine gland that controls the body’s metabolism. It is a small butterfly-shaped gland located in the front of the neck just below the Adam’s apple. The thyroid gland produces the hormones tetraiodothyronine (T4) and triiodothyronine (T3).

Together these hormones regulate how your cells use energy. The pathways by which cells use energy is called metabolism. Your body’s general metabolism determines blood pressure, heart rate, and weight.