I've never been a fan of most of the fat burner supplements that you can buy at your local GNC. If you can get it there, then might as well save your money and as these guys are saying put your time into nutrition and excercise. Problem is that they have a lot of different ingredients in them and it could be possible your body isn't aggreeing with one of them. I used to get the most horrible aftertaste on some of the old ripped fuels back in the day when they had ephedrine in them and potentially worked. At the very least it was a good pre-workout stim. Not sure of your background (training) and what you have tried or not tried as far as supplements.
As for the steroid suggestion, I would personally do the real deal before trying the designers. Lots of superdrol clones floating around out there.
If I might suggest taking some straight caffiene when you are doing low-moderate intensity cardio, that will give you a slight metabolic boost. Its safe enough. You could always try variations of EC, ECA, or ECY, but more care needs to be taken as you will have an elevated heart-rate. As in don't go for a hard run under the hot sun on a really humid day. Clenbuterol could be an option, but again, don't try that until you have a few years of training under your belt. There is also DNP 2,4 dinitrophenol which I think that if anything comes close to a magic fat burning compound that would be it. It works for sure, but the side effects are a bitch. With that said you really, really need some experiance under your belt before you consider that.
In summary, just don't waste money on the latest hydroxy cut. Put your time into training and diet and when the time comes look into some of the stuff that does work.