Maybe you keep a bottle in your car or in your purse. Or you grab a splurt as you check out of the grocery store or leave the doctor’s office. Hand sanitizer is one way we try to arm ourselves against the onslaught of germs we face in the world.

But how effective is hand sanitizer? It depends on the alcohol content and the germs you’re hoping to tackle. In most case, you’d probably be better off washing your hands with soap and water if you can, say the hygiene experts…