If you've ever hesitated to switch to bar soap, or had someone in your household question it, you've probably heard some version of this: "But doesn't bar soap just sit there collecting bacteria?"
It's one of the most common objections we hear. And it's understandable. The image of a wet, slimy bar sitting in a puddle of water in a shared bathroom does not exactly inspire confidence. But here's the thing: the science on this is actually pretty clear, and it lands firmly in favor of the bar.
Let's walk through it.
Yes, bacteria can live on bar soap. No, that doesn't mean it's making you sick.
This is where the confusion starts. Studies have confirmed that bar soap—especially heavily used bars in public spaces—can carry bacteria on its surface. A number of genera have been found on bars tested in public restrooms. So on the surface, the concern sounds reasonable.
But here's the critical part that usually gets left out: the presence of bacteria on soap is not the same as the transfer of bacteria to your hands.
Research going back to 1965 has shown that bacteria are not transmitted from bar soap to the person using it during normal handwashing. In a landmark 1988 study published in Epidemiology and Infection, scientists inoculated soap bars with E. coli and Pseudomonas aeruginosa at levels 70 times higher than what's typically found on a used bar. Sixteen volunteers washed their hands normally with the contaminated bars. The result? Not one of the sixteen had detectable levels of either bacterium on their hands afterward.
Seventy times the normal contamination level. Zero transfer. That's a pretty definitive finding.
A 1965 study reached the same conclusion, with researchers stating directly that bacteria are not transferred from person to person through bar soap, and that soap does not support bacterial growth in a meaningful way. The CDC, for its part, makes no distinction between bar soap and liquid soap when it comes to handwashing effectiveness; it endorses both equally.
So where did the myth come from?
Liquid soap brands. Or at least, they had a very strong financial interest in keeping it alive.
The 1988 study mentioned above was actually funded by the Dial Corporation, a bar soap company that wanted to defend its product against growing liquid soap marketing. The irony is that even a study designed to examine the concern couldn't find evidence of bacterial transfer.
Liquid soap marketing leaned heavily on the "shared bar = shared germs" narrative, and it worked. By the time most of us grew up, the idea that bar soap was somehow dirtier had already taken root, not because of evidence, but because of effective advertising.
What actually matters is how you store your soap
Here's where the nuance lives: while bacteria on bar soap doesn't appear to transfer to your hands during washing, a perpetually wet, slimy bar sitting in standing water is not ideal, not because of bacteria transfer, but simply because it degrades faster, gets mushy, and feels unpleasant to use.
The fix is simple: use a draining soap dish. One that lets the bar dry between uses. This keeps the bar firm, extends its life significantly, and eliminates the soggy bar problem entirely. A good tallow soap, because of its solid fat base, also holds up considerably better between uses than most commercial bars, which are loaded with water and softer, faster-dissolving ingredients.
A note on what bar soap actually does
It's also worth clearing up a related misconception while we're here: soap doesn't kill bacteria. Not bar soap, not liquid soap, not most of what's on the market. What soap does is lift bacteria, dirt, and grime off your skin so that running water can carry it away. The mechanical action of lathering and rinsing is what does the work.
Antibacterial soaps contain added ingredients specifically designed to kill bacteria, but the FDA banned the sale of over-the-counter antibacterial soaps containing certain active ingredients back in 2016, citing a lack of evidence that they were any more effective than plain soap, along with concerns about contributing to antibiotic resistance. Plain soap, used properly, is enough.
The bottom line
Bar soap can have bacteria on its surface. That bacteria is not being transferred to your hands when you wash. The science on this goes back sixty years and has been replicated multiple times. The CDC doesn't distinguish between bar and liquid soap. And a well-made bar stored in a draining dish will serve you well, last longer than most liquid soap alternatives, and skip the plastic bottle in the process.
If you've been avoiding bar soap over hygiene concerns, you can let that one go. The bar has been cleared—quite literally.
Looking for a bar soap that lathers well, lasts, and is made with four ingredients you can actually name? Start with our Pure tallow soap (Unscented), our most popular bar for a reason.
