In order for a hand sanitizer to truly be effective at ridding hands of bacteria and viruses, it has to include at least 60 percent alcohol concentration. In fact, for alcohol-based hand sanitizers, the Food and Drug Administration (FDA) recommends a concentration of 60 to 95 percent ethanol or isopropanol, the concentration range of greatest germicidal efficacy.

But what if the facility has strict regulations on using any products that include alcohol? Take schools, for instance. In reaction to cold and flu season, many schools will supply hand sanitizer, but offering a product with high concentrates of alcohol has raised concerns because it is said to be potentially intoxicating and flammable. The same concerns are present in prisons.

Around these sensitive populations, facilities are advised to use hand sanitizers with little to no alcohol concentration. The FDA does recognize these as useful options where soap and water are not available, but there is less evidence to date of their effectiveness.