I think it's contributed to a built up tolerance. I use caffeine pills esp. during a long 12 hour night shift. I started off with 2 pills (400 mg.) and was zooming fine. Now I could take 3 pills at once and not feel a thing. I'm not sure, but the lipo/ephedra has alot more zoom
![Big Grin](images/smilies/biggrin.gif)
than amp does. If you're used to alot of ephedra alkaloids then switch to something like amp with 200 mg or so of caffeine, you won't feel a thing IMO.