Washing hands and using hand sanitizer are two important steps to take to avoid getting sick or spreading germs to other people. However, there is confusion about how they work and why washing hands is better than using hand sanitizer. Here’s what you need to know.
Hand Washing vs Hand Sanitizer Key Points
Hand sanitizer kills germs, while soap washes them away.
Soap and water is better than hand sanitizer because it affects all germs, while hand sanitizer does not.
Both methods can dry skin, so it’s a good idea to apply a moisturizer after sanitizer or washing hands.
Why Hand Sanitizer Works
There are different types of hand sanitizer. Some contain antibacterial and antiviral chemicals, such as benzalkonium chloride. Most rely on alcohol as a disinfectant. Hand sanitizer containing between 60% and 90% ethanol or isopropyl alcohol kills 99.99% of non-spore forming bacteria in under 30 seconds. But, hand sanitizer isn’t perfect. Bacterial spores are unaffected. The type of bacteria that produce these spores can cause food poisoning, diarrhea, and other problems. Hand sanitizer kills some viruses, like coronavirus and most cold and flu viruses, but it doesn’t work against all viruses. Some of the alcohol is absorbed through the skin, plus alcohol makes skin more permeable to other chemicals. Alcohol dries skin out and kills “good” bacteria along with the germs. Hand sanitizer certainly has its place, but it’s not as effective as hand washing and not as friendly to your skin.
Why Washing Your Hands Works
Contrary to what you might think, washing your hands does not kill bacteria, viruses, or other pathogens. Hand washing works by mechanically removing germs from hands. You don’t even need to use soap to see a benefit, but it helps. Washing your hands with just water reduces bacteria by 77%, while washing your hands with soap and water reduces bacteria by 92%. Washing your hands with soap and water for 15 seconds reduces bacteria by 90%, while extending the time to 30 seconds removes about 99.9% of them. Viruses don’t live long on human hands, but they are also rinsed away by water.
The reason soap is more effective than simple running water is because it removes oily and waxy compounds that can trap bacteria. It acts an emulsifier, partitioning particles inside tiny sphere called micelles. The water washes away the trapped debris with ease, but the downside is that protective oils are also washed away. Super-fatted soaps help combat this issue, as they don’t strip skin as much. Detergents work much like soap, but they are even more drying.
The Case Against Antibacterial Soap
Antibacterial soap actually does kill bacteria and viruses. These products usually contain Triclosan, triclocarban, benzalkonium chloride, benzethonium chloride, or chloroxylenol. However, some of these ingredients cause health problems. Also, research shows antibacterial soap may encourage the development of antibiotic-resistant bacteria. Finally, antibacterial soap doesn’t reduce the amount of germs on hands more than just using regular soap and water. Health experts generally recommend the use of normal soap over antibacterial soap.
Don’t Over-Use Products
Hand washing removes most infectious agents, but the skin has its own bacteria called “resident flora” that help protect against disease by out-competing pathogens and aiding in keeping skin acidic. The acidity of skin slows the growth of pathogens. Hand sanitizer and over-use of soap remove resident flora and dry skin. Hand washing is best using warm or cool water and not hot water because hot water dries skin out more. Rough, damaged skin surfaces have more cracks where pathogens can harbor. Dry skin can spread germs because it can flake away, taking bacteria and viruses with it. So, it’s important to follow up hand sanitizer or hand washing with a good moisturizing lotion to keep skin healthy.
References
- Aiello, A.E.; Larson, E.L.; Levy, S.B. (September 2007). “Consumer Antibacterial Soaps: Effective or Just Risky?”. Clinical Infectious Diseases. 45 (2): S137-47. doi:10.1086/519255
- Burton, M.; Cobb, E.; Donachie, P.; Judah, G., Curtis, V., Schmidt, W.P. “The effect of handwashing with soap or water on bacterial contamination of hands.” Int J Environ Res Public Health. 2011 Jan;8(1):97-104. doi: 10.3390/ijerph8010097
- Lau, C.H.; Springston, E.E.; Sohn, M.W.; Mason, I.; Gadola, E.; Damitz, M.; Gupta, R.S. “Hand hygiene instruction decreases illness-related absenteeism in elementary schools: a prospective cohort study.” BMC Pediatr. 2012;12:52.
- Rabie, T.; Curtis, V. (2006). “Handwashing and risk of respiratory infections: a quantitative systematic review.” Trop Med Int Health. 2006 Mar;11(3):258-67.
- Sandora, T.J.; Shih, M.C.; Goldmann, D.A. (June 2008). “Reducing absenteeism from gastrointestinal and respiratory illness in elementary school students: A randomized, controlled trial of an infection-control intervention”. Pediatrics. 121 (6): e1555–62. doi:10.1542/peds.2007-2597