Figured I would post this from that link above:
The bottom line here is that although the synephrine formulation seemed to have a mild effect, the ephedrine formulation outperformed synephrine across the board for elevating metabolic rate and shifting respiratory exchange ration toward fat burning. When you compare a synephrine based mixture to an ephedrine based one for fat burning potential, the ephedrine formulations appear to have the edge, based on available research.
Synephrine and ephedrine act differently upon alpha and beta adrenergic receptor sites. Ephedrine is an indirect and direct acting beta agonist with relatively slight activation of the alpha receptors; synephrine is a direct acting alpha agonist with relatively slight activation of beta receptors, via release of norepinephrine and epinephrine. This is important when attempting to determine the potential for fat burning, because the bottom line is that beta receptors, especially beta-3 receptors, are the key to burning fat.
CROWLER
