The thyroid gland is a ductless gland in your neck. It secretes hormones which regulate your growth and development by controlling your food metabolism energy usage sleep patterns etc. The thyroid stimulating hormone (TSH) is produced by the pituitary gland. It stimulates the thyroid gland to produce the two important hormones -thyroxine (T4) and triiodothyronine (T3). The two thyroid hormones circulate in the blood in two forms - bound to a carrier protein and unbound or freely circulating. The cells of the body use only the unbound T3 and T4. The T3 hormone is crucial in maintaining the metabolism and