synephrine makes ephedrine or norephedrine products work better. i also have more energy than with a product that does not contain it. plus it curbs your appetite more.
why do you take a break from ephedrine? i just learned, that you can just keep taking it, until you're done loosing fat, because the fatburning properties won't become less, only the stimulating ones (meaning the intense energizing feeling you experience at first will be less intense).