I can only speak from my own experience and I am sure it doesn't have the same effecton everyone. I tried hydroxycut and it made my heart race and sweat profusely. I could actually feel my heart thumping in my chest after taking it and then working out. I got a bit scared of it's effects and stopped taking it. Since then, I started taking CLA and L-Carnetine together and it seems to have a milder, yet effective effect on me!
~ Soldier On ~