The Science Behind Hand Sanitizer

The Science Behind Hand Sanitizer

Ever notice how many people use hand sanitizers? Every mom has an extra one in their diaper bag, teachers stash the giant ones in a desk drawer and whip it out the moment a student gets sick, nurses actually clip them on to their person! 

But is hand sanitizer really better than washing your hands? How does it "destroy 99.99% of germs?" And how does it work? 

These are the questions we will be answering today!

Types of Hand Sanitizer

The first thing you should know is that there are three main types of hand sanitizers: alcohol based, ammonium compound based, and “natural” ingredients based. 

The most notable compounds for non-alcohol based sanitizers are benzalkonium chloride and benzethonium chloride. These agents are less effective than alcohol at destroying bacteria and can promote anti-resistant diseases and bacteria.

“Natural” based hand sanitizers generally contain tea tree oil and thyme. While these agents may kill some germs, they are not as effective as alcohol-based hand sanitizers. In fact, the CDC actually recommends only alcohol-based hand sanitizers. 

Good news is that most of the hand sanitizers people buy and that are marketed to you are alcohol based. So in this article, we are only going to be talking about alcohol based ones. 

How Effective Are They?

Hand sanitizers biggest selling point is that they destroy germs, but is it just a marketing ploy with clever wording? 

Yes and no. 

Alcohol’s disinfecting qualities comes from it’s ability to denature proteins in SOME germs. Not all germs have the same cellular structure so alcohol won’t combat against germs that don’t have an envelope or protein cellular wall.  

This is why hand sanitizers are so effective against bacteria. Bacteria are single celled micro organisms made up of a fatty lipids cellular wall surrounding a core of genetic material and proteins. 

Hand sanitizers break down the fatty lipid wall of bacteria to expose its core to the alcohol. Once the alcohol hits the core, it starts to break down the protein in the cell until the bacteria falls apart and can no longer function. In fact, when used correctly, sanitizers kill over 99% of bacteria on your hand.

But what about viruses? After all, as soon as flu season starts it seems like everyone is carrying a bottle of Purrel in their purse or hidden in their desk at work. 

This is where the yes and no part of killing germs comes into play.

Viruses aren’t like bacteria where they are all structured alike. While all viruses are essentially packets of DNA floating around that feed off the material of other cells they come into contact with, some are encased in a protein coating and some aren’t.

Viruses that have this protein envelope such as the flu virus (influenza) and H1N1 are denatured just like bacteria. Other viruses that don’t have this coating can’t be destroyed because the alcohol can’t react with them. 

Does That Make It Better Than Washing Your Hands?

The CDC has said that hand sanitizer is a good alternative for when you do not have soap and water handy and it does destroy a lot of germs, but that doesn’t mean it should be used in place of washing your hands. 

Many studies have shown that soap and water are still the champion to cleanliness and stopping the spread of bacteria and germs. This is because of the difference between how the two operate. 

As we talked about earlier, hand sanitizer breaks destroy bacteria by making them break apart and become useless. That does not mean that they are no longer on your skin. Soap and water doesn’t destroy them, but it does get them off of your skin. 

Just because you are disinfect something, doesn’t mean you are cleaning it. If you have ever used hand sanitizer after gardening or when you have been working with paints, you know that the gel just spreads around the grime and dirt. It doesn’t remove anything.

It’s like a kitchen countertop. If you cut raw chicken on your countertop, you will probably end up bleaching that area to get rid of any possibility of salmonella. You don’t bleach the area and then pick up the left over bones or meat. That would be counterproductive. The same is true with your hands and disinfectants: if you have visible dirt or your hands aren’t clean, you're not really destroying any germs. 

It has actually become an issue with people thinking they don’t need to wash their hands because they used hand sanitizer. Hand sanitizer is better than nothing but is really designed to be used between washing when needed. 

The other main reason that you don’t want to give up washing your hands is that your body is not designed to be sterile. Alcohol doesn’t differentiate between good bacteria and bad bacteria. Good bacteria is needed on our skin to balance out bad bacteria, help let our bodies know when something is wrong, and keep our skin healthy. 

Back to the idea of the counter top: it would be overkill to bleach an area just because you spilled a can of coke on it. The same is true with your hands. 

Overall, hand sanitizer is a great choice when you don't have visible dirt on your hands and need an alternative to washing your hands. When possible, though, still wash your hands with good old soap and water.