Hand sanitizer

Unless you’re a doctor, hand sanitizer might seem like it came out of nowhere. For most of your life, soap was as good as it got, maybe with triclosan for that antimicrobial kick. Then all of a sudden, a clear gel appeared—at your doctor’s office, in the checkout line at a drug store, in the lobby of your office, in your diaper bag, briefcase, or backpack.

For years, hand sanitizer was a money-loser for the company that perfected it for the mass market. But they kept pumping it out. Then, at the turn of the millennium, the US Centers for Disease Control recommended it to fight viruses and bacteria. In the 2003 SARS epidemic, another coronavirus, spread across the world. Suddenly we were swimming in it.

During the Covid-19 outbreak, it’s so in demand that stores can’t keep it in stock, and people are trading tips on how to make their own. But do you really need it? Here’s a dab.

1828: Antoine Labarraque recommends the use of “eau de javel,” a sodium hypochlorite solution, for hand hygiene.

1843: American doctor and polymath Oliver Wendell Holmes, Sr. argues that doctors not washing their hands is a cause of postpartum infections.

1846: Hungarian doctor Ignaz Semmelweis requires his staff to wash their hands with soap and a chlorine solution after making the first scientific connection between hand sanitization and disease prevention.

1860: Pioneering nurse Florence Nightingale recommends that her colleagues wash their hands “very frequently” in her Notes on Nursing.

1861: Louis Pasteur publishes his first findings on the germ theory of disease.

1946: Goldie and Jerry Lippmann found Gojo; their first product is a waterless hand cleaner inspired by watching rubber-factory workers clean their hands with benzene.

1966: Nursing student Lupe Hernandez combines alcohol and gel to create a sanitary hand cleaner for when soap and water aren’t available.

1981: The US Centers for Disease Control publishes its first national hand hygiene guidelines.

1988: Gojo introduces Purell, a gel-based ethyl alcohol hand sanitizer.

1997: Germ-X, Purell’s biggest competitor, is introduced.

2002: The CDC revises its hand-hygiene guidelines, recommending the use of hand sanitizer.

2003: Hospital use of alcohol-based hand sanitizer is up 50% over 2001.

2018: Two inmates in Oregon get drunk on hand sanitizer in a jail van and steal an ATV.

It’s a pretty simple formula: Alcohol kills the germs, glycol provides the easy-to-apply gel texture, and the rest of the ingredients repair or protect your hands from the alcohol (pdf), or add fragrance to the product.

Hand sanitizer doesn’t work on all pathogens, but it’s effective on many viruses including Covid-19. It’s an “envelope virus” with “an outer envelope that’s composed of proteins and a fatty material called a lipid.” That envelope is formed because one end of the lipid is attracted to water and the other is repelled, so they align, forming a wall made of weak, non-covalent bonds. Ethanol (the stuff that makes your booze boozy) and isopropyl alcohol (rubbing alcohol) also have hydrophobic and hydrophilic ends, and they’re tiny molecules—they can wedge their way into the envelope and dissolve it, physically tearing apart the virus. Bonus: it denatures proteins as well, something you can observe with eggs and rubbing alcohol.

More alcohol isn’t necessarily more effective. Alcohol coagulates around the proteins and clogs up the process; it needs a balance of water to keep penetrating into the virus to destroy it. That’s why the concentration of alcohol in hand sanitizers is usually around 70%. While pathogens can build resistance to antimicrobial additives like triclosan, scientists have found no evidence of resistance to hand washing with regular soap and water, or to alcohol-based hand sanitizer—though there’s some evidence that certain “innovative” bacteria have become “more tolerant” of alcohol.

You can use hand sanitizer to preserve DNA samples, giving scientists in isolated places and amateurs a low-cost, easy-to-find way to save them for the laboratory—when there’s not a pandemic going on, at least.

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11: Items on The Strategist’s list of the 13 best hand sanitizers that were sold out on Amazon as of press time (the other two were only available through third-party sellers)

>1 million: Listings of hand sanitizer Amazon has removed for false advertising or price gouging

1,400%: Increase in demand for hand sanitizer from December 2019 to January 2020

60%: Minimum alcohol content hand sanitizer should have to be effective on coronavirus

1.5: Years it took to develop Purell

10: Approximate number of years GoJo lost money on Purell

$266 million: Estimated sales of Purell in 2016

73%: Increase in hand-sanitizer sales from late January–late February 2020

100,000: Gallons per week of “NYS Clean” hand sanitizer that New York State will shortly begin making, using prison labor

$0.37: Price per ounce of Purell

$35: Price per ounce of Byredo Suede hand sanitizer, with “notes of bergamot and pear”

If you can’t find hand sanitizer anywhere, you might have the ingredients to make your own on hand, or at least find them easier to come by at the store. Popular Science has two different recipes: a recipe from the World Health Organization, and a gel sanitizer using 91% isopropyl alcohol, aloe vera gel, and tea tree oil. But just because the list of ingredients is simple doesn’t mean it’s simple to make, so you might end up with something that kills viruses but wrecks your skin, or something that feels okay but doesn’t do the job, which is why experts are currently wary about DIY hand sanitizer. And definitely don’t use vodka—there’s not enough alcohol in it. Hand sanitizer should be a minimum of 60% alcohol, and vodka is around 40% on the high end.

Dr. Lance Price, a professor at George Washington University’s Milken Institute School of Public Health, tells Quartz that you can also buy a bottle of 70% isopropyl alcohol and simply pour some on your hands, and then soap up when you get the chance. If you settle for that, you’ll probably want to moisturize as well.

You can get drunk on hand sanitizer. But you really don’t want to—the isopropyl alcohol in it can cause blindness, organ damage, and even death. Despite pearl-clutching panic over teenagers mixing hand sanitizer with mouthwash to make a cocktail far stronger, and even less palatable, than a shot of mint schnapps, the bigger risk is to younger children who sample the stuff because of its often tantalizing flavors, rather than with the intention of getting a buzz. “Since 2010, poison control center hotlines across the United States have seen a nearly 400% increase in calls related to children younger than 12 ingesting hand sanitizer, according to new analysis by the Georgia Poison Center,” CNN reported in 2015. A Purell spokesperson told the New York Times in 2016 that the company adds unpleasant flavoring to discourage sanitizer sipping, intentional or otherwise.

Commercial hand sanitizer has more ingredients than the DIY recipes that are making the rounds. In Ingredients with George Zaidan, the host explains what each one does, and tries to cook his own.

Tl;dr: Yes, but generally not as well as washing your hands. And you’re probably doing it wrong.

Hand sanitizer doesn’t wash off dirt and grease like soap, which makes it less effective. That’s one reason it’s particularly useful in a hospital setting, where hands stay pretty clean. To work, it has to be done as carefully as a good handwashing. You need a lot: 3 mL, or perhaps more if you have large hands, rubbed all over and allowed to dry for 10–15 seconds. That’s a “palmful,” not a little drop.

Even then it’s still not superior to soap and water. The consensus is to use it for its intended purpose—to clean your hands when you can’t get to the sink—while sticking to soap and water as the gold standard.

Why does good old fashioned soap work so well? Pall Thordarson, a professor of chemistry at the University of New South Wales, explains in a lengthy Twitter thread. The underlying chemistry is similar to why alcohol-based hand sanitizer works, too.