hair does not become resistant to minoxidil. Any stories you heard about that are because Minoxidil does not stop the balding process. It gives you extra hair while you use it, but the hairs keep dying at the same rate. If you get off, you go to where you would have been if you had never been on it. If you stay on, you keep losing hair just as before. People think there is resistance going on, but it is just the hairs dying from not being protected. The propecia you are using should keep the hairs from dying, though.