Mysteriously slick subway poles, a sneezing colleague, the arrival of flu season: These are all reasons to be grateful for having a bottle of alcohol-based hand sanitizer within reach. Yet in an era of superbugs — bacteria that become resistant to antibiotics — and fears about being too clean, you might wonder whether constantly pouring Purell into our palms is doing more harm than good. 

 Absolutely not, according to Elaine Larson, a professor of epidemiology at the Columbia Mailman School of Public Health and the School of Nursing. “Superbugs are not arising from topical antiseptic products,” Larson said. “Primarily, they’re arising from the use of systemic antibiotics.”

 Michelle Barron, a professor at the University of Colorado School of Medicine who specializes in infectious disease, affirmed that assessment. “Our hands become contaminated by things we touch. The intent of sanitizer is to clean your hands” of bacteria, viruses and germs in general. “The rise of superbugs is a function of the push and pull of antibiotic use.”

 Nor is there any compelling evidence that overuse of hand sanitizer could somehow compromise your immune response — which seems to be a misapplied extrapolation of the hygiene hypothesis, or the idea that being “too clean” can hamper a child’s immune system. “You’re killing the organisms that you’re picking up in the environment,” Larson said, not the normal bacteria that grow on your skin.

 One recent study has raised questions about frequent usage of alcohol-based hand sanitizer in hospitals. A 2018 paper, ­co-written by Timothy Stinear, a researcher at the University of Melbourne's Doherty Institute for Infection and Immunity, found that the bacterium E. faecium is becoming “more tolerant” to alcohol-based hand sanitizers in hospital environments. “Any environment where we repeat the same action, with the same chemicals, over and over, those bacteria and other microorganisms that can survive best under those conditions will come to dominate that environment,” Stinear wrote in an email.

 At the moment, however, that shouldn’t dissuade the general public from using the products, Larson said. “What we know right now is that alcohol hand sanitizers are the fastest and best.”

 The concept of disinfecting our hands with antiseptics is a medical innovation that dates to the early 1820s, when doctors started moistening their hands with liquid chlorides to help contain the spread of contagious diseases. But it wasn’t until the 1990s that water-free antiseptic cleansing started becoming widely accepted practice in U.S. hospitals. In 2002, the Centers for Disease Control and Prevention published a hygiene guide that recommended using hand sanitizers instead of soap and water in hospital settings.

 “The way alcohol-based hand sanitizers work is basically by busting the cell wall of germs” and thus killing them, Larson said. Compared with soap and water, sanitizers are a convenient alternative when you’re on the go and can also be more effective in general: If you did the same 15-second wash with alcohol hand sanitizer vs. soap and water, “alcohol is just more potent,” Barron said.

 At first, hand sanitizers were found mostly in occupational settings such as hospitals and restaurants. In 1988, a company called GOJO developed a hand sanitizer for health-care and restaurant employees to use on the job; by 1997, its product, Purell, was being sold to the general public. Germ-X released its own formulation to consumers around the same time. In the years since, new products have proliferated from brands such as the Honest Company, Dr. Bronner’s and Mrs. Meyer’s, while various retailers have introduced generic versions. According to a report published by Credence Research in May 2017, the global market for hand sanitizer was predicted to reach close to $3 billion by 2025, an increase of 12.9 percent.

 “Busy consumers are increasingly looking for easy, on-the-go wellness products, and hand sanitizers allow them to get a fresh boost while out and about,” says Harriet Kilikita, an associate lifestyle editor at the trend forecasting organization WGSN, via email. She added that herbal formulas are becoming more popular and that brands are experimenting with packaging to come up with “more playful or Instagrammable designs.”

With all the hand sanitizer products out there, there are a few points consumers should remember. First, hand sanitizer’s effects are short-lived. “It literally lasts for that moment, and then you touch something, and you’ve recontaminated your hands,” Barron said. That’s why resisting the urge to touch your eyes, scratch your nose, or put your fingers against or in your mouth is another important practice for keeping bacteria and viruses at bay.

 Sometimes, water and soap are preferable. While alcohol-based hand sanitizers kill more than 99 percent of germs that infect humans, said Jennifer Lighter, an epidemiologist and pediatric infectious disease specialist at New York University’s Lagone Health, they don’t kill spores from bacterium such as C. difficile. Nor is hand sanitizer as effective as soap and water at preventing the spread of norovirus. That means that whenever someone is experiencing gastrointestinal issues, washing hands is a must.

 What about products that reflect wider wellness trends, such as those that add herbal fragrances or essential oils or are advertised as natural? Just make sure their ingredient list includes 60 to 80 percent ethyl alcohol, which is the ideal range for efficacy. (“Alcohol is natural,” Larson pointed out.) Alcohol-free products, which CDC research has found are less effective at killing germs, employ a variation of antiseptic active ingredients, such as Benzalkonium chloride.

 The bottom line: “Alcohol sanitizers, natural or not natural, are safe, or safer than anything else to clean your hands with,” Larson said. “Unless you’re putting sanitizer on so often that your skin breaks down, right now I don’t see any reason, or downsides, to using it.” She does have one caveat: “It gets gooey or sticky after a while.”

Elizabeth Kiefer is a New York freelance writer who covers wellness issues.

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