Should You Use Hand Sanitizer Before or After Washing Your Hands?

If you've been paying attention to global news at all for the past month, you've probably heard tales of the shortages on hand sanitizer and the importance of washing your hands. Yet you know, as you live your daily life, that hand washing isn't always convenient or possible. Hand sanitizer is often the only available option, and these days that's not even a sure thing unless you're bringing the sanitizer yourself. So which is better? Should you use them both? Are there drawbacks to either? Let's dig into the topic and discuss it.

How Hand Washing Works

Hand washing is the premier go-to means of cleansing your hands. That is, assuming it's done right. Doing it right means three things:

  • Using soap.
  • Washing for long enough.
  • Making sure to get every part of the hands.

Washing with water alone is enough to get things like dirt off your hands, but it can't penetrate and remove oils on your skin, and it won't denature proteins or kill microorganisms. That's what the soap is for.

Soap – any kind of soap, you don't need antibacterial soap or anything of the sort – is a powerful chemical, even though you might not think it. To understand why it works, you have to understand how things like bacteria and viruses work.

Viruses, for example, are basically a strand of RNA protected by proteins and lipids. The RNA is what allows the virus to replicate, when in a particular environment. The proteins do things like open up cells of living creatures to penetrate them, provide building blocks for the virus to replicate, and so on. The lipids are a fatty layer that protects the rest of the virus from attempts to destroy it.

The Soap contains chemical structures that are slightly similar to the lipids in a virus. The difference is, the soap is chemically more aggressive at binding to molecules, including the lipids of the virus itself. The soap literally tears the virus apart. Water facilitates this process.

Water is also important because it washes the soap-and-dead-virus crud away. The denatured viruses aren't dangerous, but the soap might not kill EVERY virus on your hands – they're very tiny, so there can be trillions of them on your hands at any given time – so washing them away is equally important.

As for duration, well, take a look at your skin. Really get up close and look at it. Do you see all those tiny lines, cracks, and wrinkles? Those are really, really deep when you're only a few hundred nanometers long. It takes time and aggressive action – like hand-washing – to fully penetrate those cracks and get at viruses that are hidden deep inside. That's also why hand-washing instructions pay special attention to the areas around the nails. 

Incidentally, if you want a more detailed rundown of how the soap process works, but still written in layman's terms (that is, not getting into detailed chemistry), this article is a good summary.

How Hand Sanitizer Works

Hand sanitizer is primarily a gel with a high concentration of alcohol in it. Alcohol works in a way similar to soap, breaking down and dissolving lipids and tearing viruses apart. 

Depending on the kind of hand sanitizer you buy, it may be almost as effective as soap and water, or somewhere less effective. There are some hand sanitizers with so little alcohol in them that they're basically ineffective, so watch out for those.

Good hand sanitizer should be at least 60% alcohol. Incidentally, this is why using vodka – which is typically 40% alcohol – isn't effective for sanitizing. It's better than nothing at all, but it's "stuck on a mountain with no help for weeks" level sanitization, nothing more.

There's one primary drawback to hand sanitizer, and that's the lack of rinsing. When you wash with soap and water, you then rinse off all the dirt, oils, grime, and viruses on your hands. This includes viruses that are stuck in dirt particles, viruses clumped together, and anything the soap didn't denature. 

With hand sanitizer, you're not rinsing off any of that. Anything that's still on your hands and survived the alcohol is still there. It's better than nothing, of course, but it's not perfect and should not be treated as if it is.

Some hand sanitizers include soap as an ingredient. These are better than hand sanitizers that just have alcohol, but they still aren't as good as adding water and a rinse to the mix.

Should You Use Hand Sanitizer Before or After Washing?

The question posed in the title of this post is whether or not you should layer up these two methods of sanitization. Should you use hand sanitizer and then follow it up with soap and water? Should you use soap and water and follow it up with a hand sanitizer?

Answer: probably not. There's not much benefit to doing both one after the other.

Hand sanitizer has a purpose. That purpose is to give you a "better than nothing" cleanse while you're in a situation – such as out running errands, shopping, or interacting with people – where you can't wash your hands. Even then, it's generally better to run to the nearest bathroom and wash your hands rather than rely entirely on hand sanitizer.

Hand sanitizer does not include anything protective or prophylactic. It doesn't form a barrier on your hands that makes it harder for viruses to penetrate. Your skin is that barrier, after all. Hand sanitizer's active ingredient is alcohol, and alcohol readily evaporates, leaving nothing active on your hands.

If you use hand sanitizer and then immediately go to wash your hands, you're not really doing anything besides wasting the hand sanitizer. The soap will do everything the alcohol in the hand sanitizer was doing, but better, and rinsing your hands will help as well.

That's not to say that you shouldn't use hand sanitizer if you think you'll be able to wash your hands soon. Just don't make it part of a routine.

Washing with soap and water and then using hand sanitizer is not going to do anything for you. The hand sanitizer won't do anything the soap and water didn't already do, and the alcohol will run the risk of drying out your skin and leaving it cracked and open to infection, which is the opposite of what you want. Leaving your skin barrier cracked and open gives viruses an entryway into your system they didn't have before, and requires even more scrubbing to clean.

How Best to Use Both Methods

In general, you should be washing your hands as frequently as necessary throughout the day. Every time you leave your house, wash them thoroughly when you return. If you're shopping and can manage it, wash your hands in their bathroom as available. Wash your hands before preparing food, while preparing food, and after preparing food. Wash before eating, even if you're just snacking. Wash if you're in contact with other people, and wash if you're caring for anyone who is sick. Wash after using the bathroom, of course, and wash after interacting with or cleaning up after a child. Wash after sneezing, coughing, or blowing your nose.

Essentially, any time you could come into contact with anything that could make you sick – with the current virus or with norovirus, a parasite, c.diff, or anything else – wash your hands.

Hand sanitizer should be the stopgap "I can't wash my hands right now but I need to" method. Don't use it when you have access to soap and water, use the soap and water instead. Use it when you're out and about and don't have access to a restroom.

If you're interested, the Centers for Disease Control have a flyer about when you should use hand sanitizer, found here. It's a PDF, so be aware of that before you click.

How to Properly Wash Your Hands

You've probably heard that you should spend at least 20 seconds washing your hands and that you can measure that time with various mnemonics, like singing happy birthday to yourself twice. This advice comes directly from the CDC flyer up above. Our tips are slightly different, but treat the CDC advice as a minimum.

Our method doesn't rely on singing a song, but rather just counting to five. Here's the process:

  1. Wet your hands. It doesn't matter if you use warm or cold water, it makes no difference to how effective the soap is. We prefer warm simply because it's usually more pleasant.
  2. Apply soap. Bar soap, wet soap, foaming soap, it doesn't matter. You don't need special antibacterial soap or anything else for hand washing. Specialized soaps are only useful in exotic situations, such as working with materials that normal soap won't remove, and in those cases, you should be wearing gloves anyway.
  3. Count to five while lathering up the soap all over your hands. This gets the soap into a good lather and starts to work it in.
  4. Rub your palms together for the count of five seconds.
  5. Rub the back of your left hand and fingers for five seconds.
  6. Rub the back of your right hand and fingers for five seconds.
  7. Lace your fingers and rub between them for five seconds.
  8. Scrub your left wrist for five seconds.
  9. Scrub your right wrist for five seconds.
  10. Scrub under your nails of your left hand for five seconds.
  11. Scrub under your nails of your right hand for five seconds.
  12. Rinse the soap off your hands thoroughly, taking as long as you need.

Drying your hands, ideally, should be done with something like paper towels. You can carry these with you in a Ziploc bag if you like, or rely on whatever is in the restroom you're using. At home, a hand towel works fine, but you should launder it regularly.

Air dryers can work, but there's some evidence to suggest that they can be contaminated by constant use and may not be all that clean. Paper towels at least aren't going to be used by other people before you.

How to Properly Use Hand Sanitizer

Using hand sanitizer is pretty simple, really. Squirt some of it into your hands and work it into every surface you can. As mentioned up above, you definitely want to make sure you've got a hand sanitizer with at least 60% alcohol. If possible, one that includes soap will be more effective than one that does not.

You can follow a process similar to hand washing up above, to make sure you get every surface of your hands. The CDC recommends working it into your hands for at least 20 seconds, just like with hand washing. In particular, you want to work it until your hands no longer feel wet from the sanitizer. Take advantage of that alcohol as long as you can before it evaporates.

What To Do About Dry Hands

Both soap and water, and hand sanitizer, can dry out your skin. It's a common problem among hospital workers, as well as anyone in a position to have to wash their hands frequently. This is because it strips your natural skin oils along with contaminants, bacteria, and viruses. 

A moisturizing lotion is a good idea to help restore and protect your skin. Letting it dry out can be dangerous as another vector for infection. Gloves can also help, but treat them as temporary and disposable. If you wear gloves, be sure to learn how to take them off and dispose of them safely as well.

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