starbucks?

quote:

Caffeine can serve as a stimulant in a number of ways. As a general central nervous system stimulant, caffeine increases mental arousal and stimulates the release of epinephrine (adrenaline). Caffeine also is known to stimulate mobilization of fatty acids which may have effects on fat oxidation for weight loss or endurance performance. Caffeine also encourages the release of calcium into muscle cells, where it can stimulate more powerful muscle contractions.