It’s easy to think of painkillers as tiny biological heat-seeking missiles that find your headache and blow it up. In reality, they are much less "targeted" and much more like a systemic "mute" button.

Painkillers generally fall into two categories: those that work at the site of the injury (NSAIDs) and those that work on the brain (Opioids). Here’s the breakdown of what’s actually happening under the hood.