Go off for a month and get your hormone panel done. Then stay off for another 3 months and test again. If you start seeing test levels getting back close to low end of normal then you have a chance. I have seen men go off and after a year or two gain function back. I don't know about 20 years though. You will lose a lot of muscle, gain fat and show all the signs of hypogonadism. If you recover you will gain back some of the mass and feel better. The transition is rough.