FAR-INFRARED HEAT and its therapeutic properties have been studied in Korea for over twenty-five years and its use is now becoming very popular in North America. Far-infrared heat is a form of light energy that cannot be seen by human eyes, like ultraviolet rays and X-rays. Therasage uses Far-infrared heat to deeply penetrate your body (up to three inches deep) and stimulate your blood cells to increase your body's circulation and metabolism.