Xenadrine is a kind of thermogenic. They increase your body metabolism and gives you the maximum workout when you exercise. on the other hand they contain ingredients such as Chromium, green tea extract, white kidney beans etc...those you find in Extrim actually. They help you to stabilize your insulin levels, suppress some appetite (Zantrex 7 has this horrible after taste that naturally stopped me from eating too much).

when you start taking them, take half of the recommended portion because for some people they will experience irregular heartbeat. Xenadrine is the best so far, the worst being Hydroxycut. Zantrex 7 is as good as Xenadrine, but horrible after taste...Britney Spears takes Zantrex as well I read it somewhere.

They cost like $100 plus per bottle...lasts a month. There is an imitation brand called Synedrine. It contains the bad chromium called chromium picolinate. but i found myself wanting to go to the loo after 15 mins of taking this...but Synedrine is also not bad, i could feel the tightening of my skin...

in all, i will still go back to Xenadrine after trying various brands. yeah importantly shld get the version without ephedra or they call it ma huang. some people died of complications with ma huang.