Hand sanitizers (not to be confused with antibacterial soaps, see inset below) are ubiquitous. Perhaps you carry a small bottle with you when you’re on the go. Or maybe you use the wall-mounted units that dispense them in many public places.
Available in gels, foams, sprays, and wipes—and in both brand-name and generic versions—these products, which are typically alcohol-based, are convenient since they don’t require water. But how effective are they in preventing colds, foodborne illness, and other infections? Are they harmful in any way? Some experts recommend them; others have reservations. Here are answers to some questions.
Is using a hand sanitizer a good substitute for soap and water?
It can be—depending on the particular product and situation. The best way to clean your hands is to wash them with plain soap and running water for at least 20 seconds, especially if they are visibly dirty. This creates mechanical friction to loosen and rinse away microbes. If you don’t have access to soap and water, the next best thing is an alcohol-based hand sanitizer that contains a minimum of 60 percent alcohol (typically listed as ethyl alcohol). These products kill most (but not all) bacteria and viruses on contact. They also work well against fungi but not against bacterial spores (such as those created by C. difficile bacteria). Having soiled or greasy hands, as from gardening or cooking, makes the products less effective because the grime creates a barrier to them.
Is there evidence they actually prevent colds and other infections?
Yes. For instance, in a study in BMC Infectious Diseases in 2010, office workers who were encouraged to use an alcohol-based hand sanitizer at least five times each workday were about two-thirds less likely to get sick than those who continued to just wash their hands. An earlier study found that families given hand sanitizers had about 60 percent fewer gastrointestinal infections over the next five months than families that did not receive them. But the products are not as effective against norovirus (the most common cause of gastrointestinal illness worldwide, notably on cruise ships). A 2011 study in the American Journal of Infection Control, for example, found that there were more norovirus outbreaks in long-term care facilities that favored alcohol hand sanitizers over soap and water.
What’s better: a foam, gel, or hand wipe?
As long as the product contains at least 60 percent alcohol and you use it correctly, that shouldn’t matter. A small study in the American Journal of Infection Control in 2012 found that these three forms of an alcohol-based sanitizer significantly reduced H1N1 flu virus on hands. Other alcohol-free hand sanitizers contain “natural” ingredients like tea tree oil and thyme And in contrast to guidelines from the Centers for Disease Control and Prevention (CDC), which say that alcohol-based hand wipes are less effective, the authors posit that wipes may have added benefits because they physically remove microorganisms that survive the alcohol treatment.
What other ingredients are in them?
They typically have clarifying agents, thickening agents, fragrances, dyes, preservatives, and other “inactive” ingredients. Some contain moisturizers (such as glycerin, vitamin E, and aloe) to counter alcohol’s drying effects and supposedly “leave hands soft.” If you have an adverse reaction to a product, switch to another formula to see if that helps.
How do you use a hand sanitizer?
A common mistake is not using enough. Apply the product (at least a dime-size amount) to the palm of one hand and then rub your hands together, covering all surfaces of both hands, including between your fingers and up around your fingertips and nails. It should take about 30 seconds of rubbing your hands together for the product to completely dry. Do not touch food or anything else until your hands are dry.
What about alcohol-free sanitizers?
Instead of alcohol, some hand sanitizers contain quaternary ammonium compounds (notably benzalkonium chloride or benzethonium chloride) to reduce microbes. These agents are less effective than alcohol, plus they lack evidence of real-life benefits. Moreover, they may be contributing to bacterial resistance (see inset). Other alcohol-free hand sanitizers contain “natural” ingredients like tea tree oil and thyme, which may kill some germs but not enough for them to be good alternatives to an alcohol-based hand sanitizer. The CDC recommends only alcohol-based products.