How Do Hand Sanitizers Work?

Alcohol-based hand sanitizers are the ubiquitous
little squeeze-bottle heroes of airports and hospitals, our allies against the flu and
supposedly effective against all the things that ail ya. But what’s in there? And is it true that they kill 99.99% of germs,
as popular brands claim? Most popular hand sanitizers are alcohol-based. The active ingredient is around 70% alcohol,
depending on the formulation. The alcohol can be either ethanol, which is
the same stuff that’s in your booze of choice; isopropanol, the stuff in rubbing alcohol;
or n-propanol, rubbing alcohol’s chemical sibling. They all pretty much work the same way, which
is by dissolving the outer coats of bacteria and viruses and basically exploding them. Alcohol is polar, with water-loving hydroxyl
groups. And it loves to disrupt the protein and lipid
molecules that make up both bacterial membranes and viral envelopes. When those all-important outer coats fall
apart, these disease-causing culprits literally spill their guts all over the place, leaving
them in no position to make anyone sick. But what about people who never touch hand
sanitizer because it will breed unkillable super-germs that will kill us all? That’s a valid concern with antibiotics,
which are chemicals that target some specific point in a bacterium’s life cycle. The antibiotics in antimicrobial hand soap
can lead to the emergence of bacterial strains that are resistant and harder to kill. But resistance isn’t really a problem with
alcohol-based hand sanitizers. Bacteria can’t develop resistance to having
their proteins and membranes blasted. So these alcohol-based hand rubs aren’t
going to stop working. Make sure they are alcohol-based, though — some
contain antibiotics instead of alcohol, and those do carry the risk of resistance. But alcohol and water alone do not make goo. It’s alcohol that does the germ-murdering,
but there’s other stuff in there too.The biggest one is glycerol. Glycerol is chemically an alcohol, but unlike
its cousins, it’s in there not to kill germs but to give the hand sanitizer its gooey consistency
that makes it more portable and easier to use. Otherwise it’d be like pouring vodka on
your hands. Don’t pour vodka on your hands, guys. Alcohol, water, and glycerol are all you really
need to make a DIY hand sanitizer. Throw in some hydrogen peroxide to inactivate
bacterial spores, and you’ve got a recipe that gets the U.N.’s seal of approval. But while alcohol is all you need to kill
germs, it’s not all that goes in there. Ethanol and isopropanol can dry your skin. Glycerol helps counteract that effect, but
so do a host of other additives manufacturers might put in. This often includes tocopherol [to-cough-fer-all]
acetate, a molecule very similar to vitamin E that also happens to be great for your skin,
– and familiar stuff like aloe. A host of colors and fragrances might also
go in there. None of those are necessary for the hand sanitizer
to work, but they might make your hands smell nice. Ahhh! Toasted Marshmallow! Ethanol-based hand sanitizer might also contain
bitter or bad-tasting compounds to stop the small percentage of desperate people out there
who are willing to drink it because, well, it’s alcohol. So do these chemical goo recipes really kill
99.99% of germs? Those numbers are usually the results of lab
testing. But real life is messier. And the effectiveness of hand sanitizer varies
based on how oily or dirty your hands are, how much alcohol is in there, and which germs
you’re actually talking about. Under ideal conditions, some disease-causing
germs really do get zapped at that rate, but others don’t. OH and one more thing. Hand sanitizers work best in combination with
hand washing, because they don’t physically remove dirt and gunk from your hands. So don’t forget that soap and water. Are you always packing hand sanitizer, or
an alcohol goo-phobe? Sound off in the comments, and tell us what
other everyday chemistry we should cover! Be sure to subscribe on your way out, and
we’ll see you next time.

31 thoughts on “How Do Hand Sanitizers Work?

  • I didn't know that hand sanitizers are effective at combatting viruses. I thought they were mostly effective against bacteria. Learn something every day. Of course, I'll continue to wash my hands the old fashioned way with soap and water, but I might try a bottle of that stuff, the kind with glycerin and/or aloe.

  • I've never been a fan of this stuff more so because it is equally harmful to any good defensive bacteria on my skin (never had any fear of "breeding super bacteria" like with antibiotics). And that getting rid of 99.99% of bacteria would be a net negative to my overall health because I would be more likely to pick up harmful germs faster than I build that good bacteria back up again. I understand working in an environment like a hospital or nursing home where illness is everywhere may be more applicable but in everyday life, aren't I better off with my own defense?

  • Soap and water is more effective on the whole – but hand sanitizer is nice to have for portability and for dispensers in public places where getting your hands wet is impractical.

    No matter which one you use, nothing beats being thorough and taking the required time in washing.

    There's no point in washing your hands often if all you are really doing is splashing your hands with water and not rubbing between your fingers ect. That's probably the #1 point of failure for most people.

  • Hydrogen Peroxide 3% will kill all germs on your hands.
    Like it says in the video – WASH FIRST and then apply the HYDROGEN PEROXIDE!

  • PSA: Hand wipes like Wet Ones are usually NOT alcohol-based. They are usually soaked in an antibacterial. The only ones that are alcohol-based are individually sealed, because alcohol evaporates so quickly.

  • You said that resistance isn't really a problem with alcohol-based hand sanitizers. Is this necessarily true? I mean… some cells can survive in the highly acidic environment that is our stomach, is it really that unlikely?

  • From Mr. Esquivel Advisory ( Animo Locke High School) we are still not impressed that it kills 99.99% of bacteria. Can we receive free hand sanitizers to test it out?

  • I never carry it around with myself, but I can't resist using it whenever I find one available. The feeling is so good |3

  • i have two handsanitizer one is called winter candy apple its has 68% of alcohol its from bath abd body works. the other handsanitizer i have its called equate its lemon scented its from walmart it has 62% of alcohol

  • There is only one reason to pour drinkable alcohol on your cut
    when your in a poker match and you literally get fuckin shot

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