Generally speaking, these will contain caffeine, a cocktail of other
stimulants (such
as 1, 4 DMAA, ephedra alkaloids, quercetin, etc.), and a whole bunch of useless herbs with rather snazzy sounding names and the
label «proprietary blend», which is supple - speak for «We can't tell you how little of each ingredients this contains, because then you'd know how worthless it is».