Lots of guys stay on and stimulate natural test production with HCG. The main reason why you might not want to stay on include testicular atrophy, your budget, and potential health probs relating to liver/kidney function. For me, my main concern is testicular atrophy and prostate issues from higher test levels overall. So, I stay off just long enough to get the nads back, and I take supps to keep the prostate, liver and kidneys healthy. For me, I'm back up after 4-5 weeks. That's my .02