First off, so everyone is clear, DNP is very dangerous. It is one of the few drugs in bodybuilding that can kill you. That being said, it can be used safely but it is still very rare that I think it is a good idea. Let me explain why...
The way to safely use DNP is to do everything else right first. Get lean. Get VERY lean. Then employ the DNP at a low dose for a few wks to push your conditioning that much further. Use it to take you from crazy lean condition to STUPID crazy lean condition. 250 to 300mg for 3 wks is plenty. But heres where the problems happen. If you are already lean, and not using DNP as a cruth, you know how many cals you need to eat to lose fat. You have your diet nailed. You have your cardio nailed. Everything is on track. But once you add the DNP everything is going to change. Without question, it is going to make you look like shit while you are on it. It'll rob your body of glycogen, making you flat and weak. It would be very easy at this time, to lose lots of muscle. There is a good chance you are going to need to adjust your food while on it, and basically, you're now thrown off track. All sorts of questions are going to come up. Do I need to eat more? How much more? Should I lower cardio, or keep it the same? How many days/weeks do I need to fill back out AFTER I come off DNP, in order to fill back out? I'm not saying that these things can't be figured out, but it is going to complicate your plan and every change you make is to be one more possible thing to go wrong. So the question comes up. Why not just diet a little longer? Is it worth the risk to messing up your physique, not to mention, the physical discomfort?
If you want to use it, keep the dose low and use it for just a few wks. Give yourself plenty of time to fill back out