Returned my Hydroxycut as soon as Costco send me a voluntary recall notice, all those people dropping dead and liver/kidney damage is because of lack of H2O. There's another thread that was put up right when the FDA banned it, try a search.
The only thing I use now is FRS twice daily, drink in the morning, two chews 30 minutes before I run or workout. It's not made to help burn fat, but I definitely noticed an increase in my workout performance and recovery because of the stuff.
Because I can workout longer, more calories burnt = lose weight faster.