There is some research to say that the mate derived caffeine is largely an isomer of caffeine, in that the molecule is shaped differently. This is then used to explain why mate is more potent to users without a habituation to coffee derived caffeine. However, the research is still ongoing and the isomer theory is not yet proved, AFAIK.
This sounds very dubious. Caffeine has only one stereoisomer. And if you mean a structural isomer, then it's not actually caffeine any more.
This sounds very dubious. Caffeine has only one stereoisomer. And if you mean a structural isomer, then it's not actually caffeine any more.