Clen is amazing. I found that it REALLY DOES BURN FAT. I was worried at first because I had read about all of the negative side effects and what not. WHat I found when taking it was that the stubborn fat that I PERSONALLY could not loose no matter what, that sticky fat, clen burned off. I was doing cardio and eating clean but clen gave me that extra needed edge. With that, unlike T3 there is no worry about it burning muscle. On the contrary, clen is ANABOLIC. They weight I lost was ALL FAT no muscle. I did not have that flat look. Clen went to work in ALL the right areas. The only bad thing I CAN say about it was that I could not sleep at all. It did not matter if I took Benedryl, Seroquil or any other sleep aid. I was getting like 2 hours of sleep a night for 2 weeks. THAT REALLY SUCKED. Towards the end, I was a walking zombie. I am sure some of my gains suffered as a result. My heart rate did increase as well. Nothing too extreme thou.