I think what a lot of bro's don't realize or haven't done enough research on is the fact that, yes, there is a negative feedback loop associated with the administration of exo-test, there is also a positive feedback loop associated with the administration of Human Chorionic Gonadotropin (HCG). If it werent for this positive feedback from the hcg, that is responsible for keeping the testes plump during therapy, then bro's would , in fact go into shutdown. It is the proper administration of Human Chorionic Gonadotropin (HCG) that prevents this from happening. Hope this helps give a better understanding.