Hi, new girl here, I've bought the NEW Xenadrine NRG.....not bad at all! I took the old Xen before it was pulled off the shelf & that worked really well for me. So why am I on it again you ask?....I got a big head in my size 4 and after summer was over, thanksgiving rolled around & so did I. Then I tried the other Xen EFX, which was money down the drain. This one however, does not have have me jittery or up all night AND I was able to stay working out for an hour instead of 30min. This is my 3rd day so I'll see.....Holla at yuh girl!!!