By now, most of us have already rummaged through the nooks and crannies of our homes in search of forgotten caches of hand sanitiser. We’ve unearthed sample bottles passed out as swag from who knows what event, extracted the mini-bottle from the first aid kit in the trunk of the car and dusted off the half-empty bottle taking up space under the sink. But how effective are these ancient supplies of sanitiser, really? Does hand sanitiser go bad? Well, unfortunately…
Hand sanitiser loses potency over time
As it turns out, although hand sanitiser doesn’t exactly go “bad,” it does lose its potency over time. The CDC’s recommendation is that if soap and water are not available, then a hand sanitiser with at least 60% alcohol is a good substitute.
It’s this 60% number which poses a problem: Alcohol is a volatile compound, meaning it evaporates easily. That means that bottle of hand sanitiser that’s been sitting at the bottom of your gym bag for who knows how long might now contain less alcohol than it says on the label.
Check the expiration date
Hand sanitiser is regulated by your local health body and required to have a lot number and expiration date printed on its bottle. This expiration date is usually about 2 to 3 years from the date of manufacture, and is an estimate of when the active ingredient—which for hand sanitiser is alcohol—drops below 90 per cent of what is printed on the label. If your hand sanitiser is 70% alcohol, the expiration date is the time when this percentage is expected to drop to 90% of that value, which would be 63%. That is still within the range of effectiveness, but by a smaller margin.
After you open the bottle, the percentage of alcohol will drop as it is exposed to air. So if you have a bottle that was opened at some long-forgotten date, there’s a good chance the alcohol percentage will have dropped significantly even if it hasn’t expired yet. As the alcohol percentage drops below 60%, the sanitiser will become less effective, although it will still have some effect.
Store hand sanitiser properly
It’s important to store hand sanitiser properly. This includes keeping it out of direct sunlight, as that can lead to alcohol evaporation. It’s also important to keep hand sanitiser away from young kids, as the colours and scents of some brands can be confusing. In the U.S., the FDA is reporting increased calls to poison control centres since the start of this pandemic, mostly due to accidental ingestion of hand sanitiser. Remember, if it’s colourful or smells nice, there’s every chance your toddler will try to drink it. It’s also important to avoid storing hand sanitiser at temperatures higher than room temperature, as it is considered a flammable liquid.
Soap and water is effective
If you’re worried about the effectiveness of your hand sanitiser, your best bet is to frequently wash your hands as well (something you should be doing anyway). Hand sanitiser works well for certain circumstances, but is no replacement for plain soap and water. Hand sanitiser also doesn’t work as well when your hands are greasy or heavily soiled.
That said, if you don’t have access to soap and water, but you do have an old bottle of hand sanitiser, that is still better than nothing. Just make sure to wash with soap and water at the first possible opportunity, and stop touching your face.