How Effective Are Hand Sanitizers? | Keck Medicine of USC

How Effective Are Hand Sanitizers?

Find out what this germ-killing gel can do — and what it can’t.

Hand sanitizers have been flying off store shelves, thanks to the 2019 novel coronavirus (COVID-19) pandemic. This concoction isn’t bad at getting rid of germs when you don’t have other options for cleaning your hands, but perhaps what consumers really should be reaching for is soap and water. Here’s why.

Handwashing is better than using hand sanitizer

According to the Centers for Disease Control and Prevention (CDC), the first line of defense against viruses and disease-causing bacteria on our hands is washing them well (about 20 seconds) with plain-old soap and water.

“The mistake we make is using alcohol-containing hand rubs as a substitute for washing our hands with water and soap. Don’t do that,” says Sharon Orrange, MD, an internal medicine physician at Keck Medicine of USC and a clinical associate professor of medicine at the Keck School of Medicine at USC. “Studies consistently show that handwashing with soap and water is better than hand sanitizers. While hand sanitizers do help, they are not as effective for removing rhinoviruses [the common cold], influenza A or C. difficile from the hands.”

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Clostridioides difficile, or C. difficile or C. diff, is a nasty bacteria that causes severe diarrhea and can be life-threatening. The CDC notes that soap and water is also better than hand sanitizer at removing norovirus, another stomach bug.

Consumers should be aware of the limitations of hand sanitizers, especially as the U.S. Food and Drug Administration (FDA) recently warned makers of hand sanitizers not to make claims that their products protect against more germs than they really do.

As for coronavirus, the CDC likewise says proper handwashing should be people’s go-to strategy for prevention.

“To sum it up, the majority of evidence suggests washing hands with soap and water is better than using alcohol-based hand sanitizers in removing viruses and bacteria from the hands,” Orrange adds.

When to use hand sanitizer

That’s not to say hand sanitizer isn’t useful at all. If soap and water aren’t available, the CDC says you can use hand sanitizer that contains at least 60% alcohol, as long as your hands aren’t visibly dirty or greasy, in which case it won’t work as well to clean them.

“Generally speaking, the only time to pick a hand sanitizer is when you don’t have access to soap, water and a sink,” Orrange says. “So it’s about convenience: their ease of availability to carry in your purse or backpack, no need for water or a sink if you are traveling, and they do help in reducing microbial load.”

How to choose a hand sanitizer

According to Orrange, alcohol solutions containing 60% to 95% alcohol are most effective, usually containing either ethanol or isopropanol or a combination of both.

“A good thing to know is that ethanol, the most common alcohol ingredient, appears to be the most effective against viruses, while propanols are more effective against bacteria,” she adds. “For that reason, many hand sanitizers contain a combination of both.”

Although alcohol-based hand rubs in the form of gels are most frequently used, it doesn’t matter whether you pick a foam, gel or wipe, Orrange says. “They all significantly reduce microorganisms on the hands,” she says.

Avoid these hand-sanitizer pitfalls

There are a few things to keep in mind when it comes to hand sanitizers.

1. Alcohol-free formulations. Be wary of alcohol-free hand sanitizers, as they might be not as effective, according to the CDC. These products may not work as well on many germs and might only reduce their growth instead of killing them.

2. Proper technique. When applying hand sanitizer, make sure you use enough to cover all surfaces of your hands and rub your hands together until they’re totally dry.

3. “Antibacterial” products. Don’t confuse these with hand sanitizer. Antibacterial soaps and body washes are no longer allowed by the FDA to be marketed, as these products contain triclosan and triclocarban, which may be harmful and don’t have proven effectiveness. These chemicals may also contribute to creating antibiotic-resistant bacteria, which the alcohol in hand sanitizers does not do.

4. Skin dryness. Be aware that hand sanitizers may not be kind to your skin. “The downside is that hand sanitizers are very drying to the skin, so most alcohol-based hand sanitizers also contain glycerin, which helps prevent skin dryness, and emollients or moisturizers, like aloe vera, which help replace some of the water that is stripped by the alcohol,” Orrange says.

The bottom line on hand sanitizers

Hand sanitizers aren’t a bad thing to have on hand, especially when you don’t have access to soap and water. But, when you can, wash your hands instead.

by Tina Donvito

Do you have concerns about the best way to prevent respiratory or bacterial illnesses? Our primary care physicians can help. If you are in the Los Angeles area, request an appointment or call (800) USC-CARE (800-872-2273).