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Soap vs. Hand Sanitizer

April 23, 2020 | UCI Health
handwashing graphic

In a pinch, hand sanitizer can disinfect if it’s at least 60% alcohol.

But hands down, soap and water is the most effective way to remove chemicals and all kinds of germs, including the novel coronavirus, infectious disease experts say.

The Centers for Disease Control and Prevention (CDC) recommends frequent handwashing for at least 20 seconds to prevent the spread of the virus that causes COVID-19.

Why is soap and water better? For starters, there are limits to how well hand sanitizers disinfect.

Hand sanitizers don’t eliminate everything

Applying hand sanitizer may be easier, but even the ones with sufficient alcohol content cannot remove all types of bacteria and viruses.

Soap and water are far more effective at removing such common illness-causing germs as cryptosporidium, norovirus and Clostridium difficile. Soap also washes away bacteria as well as other viruses that are even tougher than coronaviruses.

Studies show that hand sanitizers work well in clinical settings, where hands are not heavily soiled or greasy. But in work and community settings — where people handle equipment, food or play sports — sanitizers can't clean thoroughly enough. Moreover, hand sanitizer is ineffective if too little is applied or it is wiped off before it has dried completely.

Hand sanitizers also probably cannot remove or inactivate harmful chemicals we may come into contact with. In one study, people who reported using hand sanitizer to clean their hands were found to have increased levels of pesticides in their bodies.

If you have touched harmful chemicals, experts recommend washing carefully with soap and water or as directed by a poison control center.

Bacteria resistance seen

Many studies show that sanitizers with alcohol concentrations between 60% and 95% are better at killing germs than those products with a lower concentration or or no alcohol.

Lesser concentrations of alcohol merely reduce the growth of germs rather than kill them outright. 

More worrisome is that some bacteria have begun to show a tolerance to low amounts of ethyl alcohol.

Alcohol poisoning in kids

While alcohol-based hand sanitizers are safe when used as directed, they can cause alcohol poisoning if swallowed, particularly, if a person swallows more than a few mouthfuls.

U.S. poison control centers received nearly 85,000 calls about hand sanitizer exposures among children from 2011 to 2015.

For this reason, hand sanitizers should always be stored out of the reach of young children, and used only under adult supervision.

Why is soap more effective?

Soap combined with running water is by far the best way to eliminate germs from our hands. That's because soap molecules, themselves, are very effective at destroying the surface membranes of some bacteria and viruses, including the novel coronavirus.

In addition, the lathering of hands and scrubbing thoroughly creates friction that helps lift and wash away dirt, grease and microbes under running water.

Soap takes a little time to work — at least 20 seconds to disinfect your hands completely. That's about the time it takes to sing the “Happy Birthday” song twice.

So hum or sing along as you follow the CDC’s recommended handwashing steps:

  • Wet your hands with clean running water (warm or cold) and apply soap.
  • Lather your hands by rubbing them together with the soap. 
  • Scrub all surfaces of your hands, including the palms, backs, fingers, the skin between your fingers and also under your nails.
  • Rinse your hands under clean, running water that is not too hot to tolerate.
  • Dry your hands using a clean towel or air dry them.

These steps can make all the difference in protecting you and your loved ones.

When to wash

Handwashing isn’t a one-and-done exercise. Good hand hygiene throughout the day is vital to protecting your health as well as that of others.

We touch many things in the course of a day, picking up all manner of grime and germs. The CDC recommends washing your hands:

  • Before, during, and after preparing food
  • Before eating food
  • Before and after caring for someone who is sick
  • Before and after treating a cut or wound
  • After using the bathroom, changing diapers or cleaning up a child who has used the bathroom
  • After blowing your nose, coughing or sneezing
  • After touching an animal, animal food or treats, animal cages or animal waste
  • After touching garbage
  • If your hands are visibly dirty or greasy

Protecting your skin

Because all that handwashing can leave your skin red, chapped and even cracked, the American Academy of Dermatology recommends hydrating your hands immediately after washing.

Apply a pea-sized amount of hand cream or ointment to your skin, and work it into your skin thoroughly, including fingertips and fingernails.

Dermatologists recommend using a hand cream or ointment that:

  • Contains mineral oil or petroleum jelly
  • Comes in a tube rather than a pump-bottle
  • Is labeled fragrance-free and dye-free