Seems like all these products have the exact same amount of caffeine and ephedrine. So what's the big difference? What would one want to use for what. Like xenadrine for losing weight and ripped fuel to gain muscle... I'm kinda confused especially after that big post with all the scientific data which seems to say that ephedrine is a gift from the gods. When I used to take xenadrine (i'm thinking about starting up again) and I would do aerobic exercise my heart would pump so fast and it would scare the hell out of me. I was always watching for chest pains and thinking I was gonna have a heart-attack. My dad has had 2 heart-attacks both after he was 50, but he has lived a VERY unhealthy life with very little physical activity and VERY poor eating habits. The bottle says if you have family history of heart-disease to not take it, and this where my biggest fear comes in. Any information would be very appreciated, Thank You.