Earlier this month, the FDA banned the sales of antimicrobial soaps in the US, giving companies one year to pull several common antimicrobial substances out of their over-the-counter hand soaps and body washes. This is a remarkable step forward that public health experts are applauding, but why? Why would public health experts be excited that we are removing antimicrobials from soap? Don't they help us stay healthier?
The answer is, perhaps surprisingly, probably not. Soap already does a great job of keeping us clean without any additional antimicrobials. Soap consists of amphipathic molecules -- molecules that contain both a hydrophobic section and a hydrophilic section. The hydrophilic parts make the molecules dissolve in water, and the hydrophobic parts dissolve fat and grease. When you wash your hands, the molecules clump together in little balls called micelles, with the water-loving part on the outside, and the water-hating part on the inside, along with all the dirt and grime.
When it comes to keeping you clean, these amphipathic molecules are important in a few ways. First, as stated above, they help dissolve fats and grease that normally won't mix with water. Also, the micelles, along with the foam that many soaps make, keep the dirt and germs away from your skin so that they can be rinsed away cleanly. Finally, and most importantly for our point, these molecules can actually kill bacteria. It turns out that the molecules that cells are made of are pretty similar to the amphipathic molecules in soap, and the soapy molecules can dissolve away the membranes of cells. This is also why soap feels slippery to touch, because it is dissolving away some of your dead skin cells.
Not only is soap already great at getting rid of bacteria on your skin, antimicrobials in soap may actually be harmful. Part of this is because bacteria can become resistant to antibiotic substances shockingly fast. This is a problem because then, if you get a bad infection with antibiotic resistant bacteria, there may be few good treatment options for you. There is also some evidence that some antimicrobials used in soaps may also tamper with some hormones in your body, which can lead to developmental and reproductive issues. The FDA asked soap-making companies to prove to them that the potential help of using their antimicrobial substances would outweigh the potential harm, and they were not able to.
I'm very excited about the FDA's new rule on antimicrobial soaps, because I believe that these substances have a lot of potential for harm. I do want to point out that this rule does not include alcohol-based hand sanitizers; they are fine to use because bacteria are very unlikely to become resistant to alcohol. In fact, hand sanitizer is better for your skin than soap, believe it or not. In the future, whether you use soap or hand sanitizer, don't be worried when it's missing that "antibacterial" label; it still does the job exactly how it's supposed to!
