I hate to admit it, but I'm really sensitive to stims.
One pill of (caffeine, ) or (caffeine, narigin, Horny goat weed) will give me heart palpitations and make me nuts and spike my blood pressure and I can't sleep the whole night!
here is how I deal with it: I break open a capsule of Lipo6/RPM and dump the contents (and the gel cap) into a bottle of 300ml water. I then only consume about 30 ml of it. And I get the 'stim' effects without the nasty sides! Of course, you'll have experiment to find out what is the optimal amount for you.
I then keep the remainder in the fridge. And hope the stuff doesn't break down in water. So far, the stim effects are still pretty potent (for me) even after keeping it ion the fridge for 10 days.
This is really great as one bottle of stims can last me forever, or until I get a heart .
I keep some sleeping 'sleep supps' (melationin, , GABA, chamomile) handy just in case I take too much stims.