The first thing to know is that part of your natural tiredness comes from a molecule called adenosine, which is produced by your body while it chugs along through the day. “While you sleep, the concentration of adenosine declines, gradually promoting wakefulness,” the video explains. Meanwhile, the more adenosine that builds up, the sleepier you feel.

Your morning coffee is able to hijack that process because caffeine looks a lot like adenosine to your brain cells.

Because of its similar shape, caffeine can bind to the adenosine receptors in your brain. Once the caffeine is locked into adenosine’s rightful spot though, there is no way for the adenosine to stick around — which prevents it from building up and making you sleepy.

Without the molecule that usually induces exhaustion, “our natural stimulants run wild,” Joseph Stromberg writes in Smithsonian. The result? You feel wide awake — at least for a while.