i don't know eitherr... when i take 2 of them i feel like i'm rolling on E and cokedd up at the same time.. it's weird... then when i start to come off.. i am the moodiest sonofabitch you can ever encounter.. whatever it is... can't be that beneficial for my body..
I work at GNC and have studied both of the products. stackers is just an eca while the xenadrine has the same base eca and other auxillary ingredients to assist fat burning like ginger, carnitine and tyrosine.
STACKER 2 IS A SKETCHY PRODUCT! - because they no longer list the number of milligrams of ephedra alkeloids...etc... that are in each capsule, yet they claim that is it "the most powerful" product of its kind. They are playing a little game of show and tell - see, they're telling you everything but showing you nothing