If they are the superclen, I would start really low. Try 1/8 a tab. Those puppies are really strong. The first time I ever took them, I took 1/8 a tab and my heart was beating so fast, I thought it was going to rip out of my chest. I eventually got used to it and the most I will do is 1 to 1.5/day. Some people experience really bad headaches from it, but that is not the case for me. I get the shakes really bad and they make me hungry as hell. I always have carb cravings.