To prevent coronavirus, the best thing you can do is to wash with plain soap and water for at least 20 seconds. Handwashing is especially important after going to the bathroom, before eating, and after coughing, sneezing, or blowing one’s nose. No access to soap and water? Hand sanitizer is the next best thing.

When soap and water are not available, the CDC recommends the use of an alcohol-based hand sanitizer that contains at least 60% alcohol.

Note that alcohol-based hand sanitizers can quickly reduce the number of microbes on hands in some situations, but sanitizers do not eliminate all types of germs. Soap and water is more versatile and effective. Soap is especially important when your hands are heavily soiled or greasy, or when you have come into contact with pesticides or heavy metals. The use of antibacterial or antiseptic soaps is not helpful, since coronavirus is a virus and not a bacteria.

If your only choice is hand sanitizer, then you need to make sure to use the correct concentration with the proper technique. Any concentration less than 60% may be less effective on certain types of germs, and will only reduce the growth of germs rather than kill them.

When using hand sanitizer, apply the product as directed. Put the recommended amount onto the palm of one hand and rub the product all over the surfaces of your hands until your hands are dry. The alcohol in hand sanitizer works best when you rub hand sanitizer all over your hands, making sure to get between your fingers and on the back of your hands. Do not wipe or rinse off the hand sanitizer before it is dry.

Due to coronavirus, there are shortages of hand sanitizer in some places. Many people have resorted to making their own, but this should really be a last resort. The wrong mix can render the product insufficient to help, or worse, damage the skin. Luckily, to address shortages, the FDA has issued guidelines that allow companies to temporarily prepare certain alcohol-based hand sanitizer products. As a result, you should be able to find options in your local stores or online.

Never use surface cleaners or disinfectants on your skin. These products may cause irritation, and are not for use on humans or animals.

Remember, 20+ seconds of washing with regular soap and water is always your best option. When you don’t have that option, hand sanitizer is a great backup.

For more information, check out the CDC fact sheet on hand sanitizers.