World's Most Popular Psychoactive
Caffeine is many things: a stimulant, an alkaloid, and to many, a lifesaver. By counteracting a substance called adenosine in the body, which has the purpose of inhibiting activity in the central nervous system, caffeine boosts wakefulness, focus, and coordination.
It's also the world's most popular psychoactive drug. Globally, humans consume 120 million kilograms of the stuff each year, which is pretty impressive when you consider that the average cup of coffee contains just .1 grams!