Most people experience an increase in energy. Try taking it with a simple stimulant if youre having issues with energy. Odds are the supression of appetite is making your body use more things like carbohydrates just to feed itself, allowing less for energy. This will happen with anything that supresses appetite, which is how a suppressed appetite loses fat!
But it is not an energy booster per se. That is why users stack it with OEP, Jack3d, ASGT, etc.