Can Germs Live on a Bar of Soap? | Explaining Soap Myths

Washing with soap is the best protection against germs such as viruses and bacteria. So then why is there a myth about bar soap being unsanitary? Sometimes people hesitate to use bar soap because of the worry that germs live on the bar of soap after it’s been used. We looked into this myth so you don’t have to. 

Read on to find out if there’s any truth behind this and to learn more about the science behind bacteria growth, good vs bad bacteria, and the best ways to keep your soap and your shower germ-free. 

Bar Soap Germs

Can germs live on a bar of soap? The short answer is yes, they can. But the more important thing to ask, is if this is anything to worry about?

NO: It’s highly unlikely that germs found on soap would make you ill or cause a skin infection. Studies have shown that germs can be found on bars of soap, but these are most likely from your own skin (more on that next).

But let’s say someone who’s sick uses your soap – could that make you sick too?

NO: Studies evaluating the risk of transmitting germs through a bar of soap have concluded that the bacteria left behind after washing does not transfer to the next user of the soap. This is true even when scientists applied substantially higher levels of bacteria than would normally be found on used soap. So you can rest easy that when your sneaky roommate uses your soap, you won’t catch their cold.

Bacteria & Your Skin

Not all bacteria is bad. Studies estimate that half of the cells in the human body are bacteria, many of which live on your skin, making up what is known as your skin microbiome.

When you wash with soap, you don’t actually want to kill all bacteria on your skin, since your skin’s microbiome is beneficial to your immune system. But washing with soap does reduce the number of germs on your skin which makes it easier for your immune system to function and protect you from pathogens. 

Read more about how soap works and the best germ killing soap here. 

Bar Soap Best Practices

Even though you don’t need to worry about bacteria on your bar soap, bacteria thrive in wet environments (ie: your shower) and can grow around your soap and in other areas of your shower. Here are a couple things to look out for in your shower that might be carrying germs: 

If you use a washcloth or loofah, these can deposit germs onto your soap. Bacteria can live on these shower aids because they often stay damp for long periods of time, which promotes the growth of bacteria and mold. Bacteria can also live in the slimy soap scum that results from prolonged contact with water, so leaving your bar of soap in a puddle of water after usage can promote the growth of bacteria in your shower and around your bar soap.

To limit the number of germs you’re exposed to, follow the guidelines below:

1. Rinse your soap bar under running water prior to use.
2. Lather the bar directly on your skin or in your hands instead of using a washcloth or loofah.
3. If you prefer a washcloth or loofah, wash and/or replace it regularly.
4. Keep your bar soap dry between uses by storing it in a dish with ridges and drainage, like this Soap Saver. This will keep your soap out of water between uses, keep your soap and the area around it clean, and extend the life of your bar soap.

About the Author

Alexandra Blackstone, Product Development Manager @ Dr. Squatch

Alex Blackstone is a scientist and product development expert with 10 years of experience working on major brands including Neutrogena, Aveeno, Clean & Clear, and Burt’s Bees. She has a master’s degree from Dartmouth College and a BS in chemical engineering from the University of Virginia. She joined the Dr. Squatch team earlier this year.