Hand sanitizers kill germs with alcohol. Properly formulated and applied, such a product can kill just about any bacteria or fungi you're likely to get on your hands. But not all sanitizers are the same. To protect yourself, you need to know what to look for on the bottle, how to properly apply sanitizer and when a sanitizer itself isn't going to be enough.
Concentration
To work effectively, an alcohol-based hand sanitizer should be at least 60 percent alcohol. It doesn't matter what type of alcohol the product uses--ethyl alcohol, isopropyl alcohol and other kinds all work equally well. But concentrations lower than 60 percent may not be strong enough to kill bacteria and other bugs. This applies to both gel- and foam-type sanitizers.
Effectiveness
Sanitizers you see on store shelves boast that they kill "99.99 percent" of germs. But such claims are based on lab tests, not everyday use. In the tests, subjects start by washing their hands. Scientists then apply bacteria to their hands. The subjects then apply a generous amount of sanitizer and really work it in. After that, the concentration of bacteria is measured. Out in the real world, people's hands are dirtier, they use a smaller glob of sanitizer and they have more kinds of microbes on their hands. Research cited in the Wall Street Journal says a more reasonable statement of sanitizers' killing power is 46 percent to 60 percent in any given application.
Targets
The "99.99 percent" figure is misleading in another way. It does not mean that, if you applied it to every kind of microbe in the world, the product would kill 99.99 percent of them. It means a properly applied sanitizer would kill 99.99 percent of a representative sample of common bugs. Sanitizers can't kill the hepatitis A virus, for instance. In fact, sanitizer manufacturers are not allowed to make blanket claims that their products kill viruses at all, though the products do in fact kill many viruses.
Application
To get full protection from a hand sanitizer, you need to use enough to fully coat your hands, then rub your hands together until they're dry. According to federal guidelines for health care workers, if your hands are dry in less than 10 seconds, you're not using enough sanitizer. Do not mix the sanitizer with water, as doing so drastically reduces the alcohol concentration--and, thus, the killing power. And because some bugs take longer to kill than others, do not wash your hands right after putting on sanitizer. Wash first, then apply sanitizer.
Dirt
Sometimes you have to use soap and water. Hands that are soiled with dirt, blood, feces or other grime should be washed first. The alcohol isn't strong enough to cut through the grime.
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