I've taken a few different kinds. Some I'll say are simply an energy boost for me. And others I can say do seem to help with a little extra cal burn.

BUT you have to keep in mind that a thermo doesn't just target burning fat. Primarily it's a bit of a metabolic boost. So if your diet and training aren't right, you're not going to burn off what you want to burn off; meaning if you aren't on par with everything else like you should be, you run the risk of burning off muscle over long periods of time taking those kinds of products.

Overall, I'd say treat them simply as an energy boost for your workouts, and especially don't expect them to be a 'miracle' pill. But if you have the money to spend on them, and you have everything else with your regimines in line, give it a try.