To second the idea, clen aint' a magic pill. It is slightly more efficient at promoting metabolism than your OTC thermos. But it will make you buzz. The dosage will also depend on what brand you take. Oxyflux is underdosed & seems like it takes a virtual handful to feel anything. You have to see how you handle it and then deal w/ the sides. Me personally, I get a borderline panic attack from 2 cups of coffee. Clen is a 12 hr anxiety attack coupled w/ a pounding headache at the back of my neck.
Before expecting miracles, definitely make sure the underlying diet is tight, training is good & intense & lots of water. Also don't take the stuff after 3 pm, particularly if you have a tendency to have trouble sleeping.