Question about Yerba Mate Tea

[dragon50]

I am often highly caffeinated. My favorite way of achieving the state is with guarana pills. A friend of mine suggested that I try Yerba Mate Tea. It does the trick for alertness, however, it gives me a headache (literally) that is very unpleasant. There were no other contributing factors for the headache, as I tried the tea 4 or 5 times, each time getting a headache.

I don't remember the reported caffeine content, but it wasn't an astronomical number. What ingredient in the mate gives me headaches? Is there some alcoloid that is not agreeing with me?


Thanks