dude i got liquid clen from ag guys and everyone says they are legit, but i dosed it super high and didnt feel anything either.
in all honesty, "biologically" speaking...clen doesnt give you those ephedrine like stimulant effects.
but some guys experience it.. who am i to say its placebo?
all i know is that clen didnt do shit to me, and that the science says it shouldnt give you any kind of jitters