Hand sanitizer is less effective at killing certain kinds of germs, such as norovirus and Clostridium difficile, and unlike hand washing, it cannot physically remove harmful chemicals. People may incorrectly wipe off hand sanitizer before it has dried, and some are less effective because their alcohol concentrations are too low.
Alcohol-based hand sanitizer that is at least 60% (v/v) alcohol in water (specifically, ethanol or isopropyl alcohol/isopropanol (rubbing alcohol)) is recommended by the United States Centers for Disease Control and Prevention (CDC), but only if soap and water are not available. The CDC recommends the following steps when using an alcohol-based hand sanitizer:
Apply product to the palm of one hand.
Rub hands together.
Rub the product over all surfaces of hands and fingers until hands are dry.
Do not go near flame or gas burner or any burning object during application of hand sanitizer.
