Reading this with a cup of coffee,aren't you?

The main biologically active ingredients in coffee are caffeine (a stimulant) and a suite of antioxidants.The stimulant properties of caffeine mean that you can count on a cup of coffee to wake you up. In fact, coffee, or at least the caffeine it contains, is the most commonly used psychoactive drug in the world. It seems to work as a stimulant, at least in part, by blocking adenosine, which promotes sleep, from binding to its receptor.