What hormones are produced by the thyroid gland?

The thyroid gland produces two hormones: tri-iodothyronine (T3), the active, primary intracellular hormone and thyroxine (T4), the inactive, primary extra cellular hormone. Thyroxine (T4) is produced by the thyroid gland in twenty (20) times the concentration as T3. T4 must be absorbed into the cells where it must be converted to T3 in order for the cells to function at a healthy metabolic rate. If T4 is not properly assimilated into the cells or converted to T3 within the cells, then hypothyroidism results. It is not the level of thyroid hormone in the blood that is important, but rather, how much T3 is present within the cells. This is why blood tests are inconclusive and oftentimes do not correlate with a patient’s clinical symptoms. The thyroid hormone, T3, enables the cells to produce and use energy, which is ultimately converted to heat, giving the body its temperature.