Listening to this I realized that caffeine is a much more important enzyme than I ever realized, i.e. 52% less blood flow to brain after one small cup of coffee, causes enlarged prostrate, etc.
Caffeine is a central nervous system stimulant of the methylxanthine class. It is the world’s most widely consumed psychoactive drug. Unlike many other psychoactive substances, it is legal and unregulated in nearly all parts of the world. There are several known mechanisms of action to explain the effects of caffeine.