Eli5: How come hand sanitizer has an expiration date? What exactly happens once it goes past it?

Question

Eli5: How come hand sanitizer has an expiration date? What exactly happens once it goes past it?

In: Chemistry

Answer 1

It becomes less effective. Hand sanitiser works best the higher the alcohol content. Now, of the ingredients in hand sanitiser alcohol easily evaporates. This means over time as the alcohol in the hand sanitiser evaporates the less effective it becomes. You may think that you’re properly sanitising your hands but you’re not.