Hand sanitizer

Hand sanitizer (also known as hand antiseptic, hand disinfectant, hand rub, or handrub) is a liquid, gel, or foam used to kill viruses, bacteria, and other microorganisms on the hands. It can also come in the form of a cream, spray, or wipe. While hand washing with soap and water is generally preferred, hand sanitizer is a convenient alternative in settings where soap and water are unavailable. However, it is less effective against certain pathogens like norovirus and Clostridioides difficile and cannot physically remove harmful chemicals. Improper use, such as wiping off sanitizer before it dries, can also reduce its effectiveness, and some sanitizers with low alcohol concentrations are less effective. Additionally, frequent use of hand sanitizer may disrupt the skin's microbiome and cause dermatitis.

Alcohol-based hand sanitizers, which contain at least 60% alcohol (ethanol or isopropyl alcohol), are recommended by the United States Centers for Disease Control and Prevention (CDC) when soap and water are not available. In healthcare settings, these sanitizers are often preferred over hand washing with soap and water because they are more effective at reducing bacteria and are better tolerated by the skin. However, hand washing should still be performed if contamination is visible or after using the toilet. Non-alcohol-based hand sanitizers, which may contain benzalkonium chloride or triclosan, are less effective and generally not recommended, though they are not flammable.

The formulation of alcohol-based hand sanitizers typically includes a combination of isopropyl alcohol, ethanol, or n-propanol, with alcohol concentrations ranging from 60% to 95% being the most effective. These sanitizers are flammable and work against a wide variety of microorganisms, but not spores. To prevent skin dryness, compounds such as glycerol may be added, and some formulations include fragrances, though these are discouraged due to the risk of allergic reactions. Non-alcohol-based versions are less effective and should be used with caution.

The use of alcohol as an antiseptic dates back to at least 1363, with evidence supporting its use emerging in the late 1800s. Alcohol-based hand sanitizers became commonly used in Europe by the 1980s and have since been included on the World Health Organization's List of Essential Medicines.