The regulation and production of testosterone is the responsibility of the hypothalamus and pituitary gland. The body does a nice job on its own of balancing these levels when functioning properly. If TRT is right for you this is not happening. When testosterone levels are manipulated via injections the hypothalamus and pituitary will respond by signaling the testes to decrease natural production. For those patients that suffer from Low T the body is either not signaling production effectively or it is not able to produce effective levels once given the signal to do so. Therefore, patients that discontinue therapy will revert back to their pre therapy baseline levels. Those levels have been diagnosed as being inadequate.