Bar soap is quite possibly the oldest cleansing method out there, having been around for thousands of years. While it never really went away, I’ve noticed that it cycles back every so often making its way into the spotlight.
In this post, I’ll give you my honest opinion about bar soap and how it affects your skin based on both personal experience and over 30 years of working hands-on with clients.
What’s the Difference Between Bar Soap and “Non-Soap Cleansing Bars?”
Just because something comes in bar form doesn’t automatically mean it’s bar soap. There’s an important distinction between traditional bar soaps and non-soap cleansing bars.
So what exactly is bar soap? True bar soap is made by mixing an oil with something really alkaline (meaning it has a high pH). This is usually either sodium hydroxide or potassium hydroxide. One common combo, for example, is coconut oil and sodium hydroxide. Combining the two triggers a chemical reaction that results in sodium cocoate, which is the main cleansing agent and what you’d see on the ingredient label.
One of the biggest problems with traditional bar soaps is that they have a very high pH. They range anywhere from 7.5-10, whereas the skin’s natural pH hovers around 5.5. If the skin is put into an alkaline state long enough, it can easily lead to moisture barrier damage.
Non-Soap Cleansing Bars
Non-soap cleansers have a completely different chemistry than bar soaps. Put simply, they’re a waterless version of a traditional cleanser that has been solidified into bar form. (Cosmetic chemists call them SynDet bars, short for “synthetic detergent.”)
Instead of combining an oil and a hydroxide, these are made using traditional surfactants, which are the main mechanism your “regular” cleansers use to remove dirt and oil from the skin. Surfactants are taken in their solid form, heated up, and pressed together into a solid bar before being left to cool. The cleansing agents found in these bars are part of a group of synthetic surfactants called isethionates. For reference, the most classic example of a non-soap cleanser is the Dove Beauty Bar, which uses a surfactant called sodium lauroyl isethionate to cleanse.
Because these bars aren’t made by adding a hydroxide, they tend to be more pH-balanced than bar soaps and less likely to strip the skin.
Is Washing Your Face With Bar Soap Bad for Your Skin?
Yes, I believe using bar soap to wash your face is bad for your skin. While non-soap cleansing bars aren’t as bad as traditional bar soaps, they’re still not ideal. Let me explain why.
Since all cleansing bars are waterless, they have low water solubility. This means you have to rinse VERY thoroughly with lots of warm water to get them off the skin. It’s not uncommon for bars to leave a residue behind. Ever had that “squeaky clean” feeling after using a bar of soap? Yeah, that’s from the residue it left on your skin. This is where the high pH of a bar can start to become really problematic; having something alkaline on your skin for an extended period of time won’t do you any favors.
But even if a bar is pH balanced, having that residue on the skin means your other products won’t penetrate as well. At best, you’ll be wasting your money by not getting the most out of your products. At worst, it could lead to dehydration and a compromised moisture barrier (hello, irritation).
Of course, no matter how you cleanse, make sure you’re following it up with the right routine for your skin type to keep your skin healthy and balanced. Another tip? Apply your moisturizer within one minute of cleansing to avoid moisture loss—I call this the “Golden Minute Rule.”
Are Cleansing Bars Good for Sensitive Skin?
There is some speculation that cleansing bars are a good option for those with sensitive skin since they tend to be free of preservatives (which is possible thanks to their lack of water content). I would argue this is only beneficial if you have a known preservative allergy, which isn’t all that common. I think the main reason some people with sensitive skin do well with cleansing bars is that the ingredient lists are usually short and simple. This doesn’t necessarily mean cleansing bars are better, it probably just means you’ve eliminated something that was an irritant for you.
“Sensitive skin” can also mean any number of things, and a cleansing bar isn’t an automatic fix. What type of skin sensitivity do you have? What exactly are you sensitive to? For example, many cleansing bars contain fragrance, which is more likely than most preservatives to irritate sensitive skin. Skin sensitivities are nuanced, and I don’t believe bar cleansers are the answer. Instead, I would prefer you use a basic, gentle liquid cleanser. They’re definitely out there, companies just tend to add more bells and whistles to liquid cleansers because it’s so easy to do. To help you get started, here are four ingredients your cleanser should never contain.
Does Bar Soap Affect Acne?
There isn’t much evidence, either way, to support bar soaps improving or exacerbating acne. Personally, I wouldn’t recommend someone who is trying to get breakouts under control use this as a cleansing method. The last thing you want to do is cause irritation or disrupt your barrier since this will only make breakouts worse. Because bar soaps and bar cleansers are more likely to do both, I’d steer clear. Instead, follow these 17 tips that might help banish your breakouts for good.
What’s the Best Way to Cleanse Your Skin?
The best way to cleanse your skin is by using a non-drying, sulfate-free cleanser for your specific skin type and concerns. Beyond choosing the right cleanser for your skin type, you’ll want to make sure you’re cleansing your face correctly in both the morning and evening.
So, What’s the Bottom Line?
Throughout the years, I’ve personally experimented with so many bar soaps. I used to go to France quite a bit to visit family and was always tempted to try fancy French bar soaps. There’s something about them that just seems so luxurious and wonderful. Sadly, every single time I would use one, my skin would immediately feel tight and look dehydrated. I’ve seen the same thing happen to a lot of my clients as well.
At the end of the day, I believe using a non-drying, sulfate-free cleanser in its liquid form is much better for the skin than a bar cleanser, whether it be traditional bar soap or the newer generation of cleansing bars. While the newer bars aren’t as stripping or drying as traditional bar soaps, they can still leave a film on the skin that could cause irritation and make it harder for products applied afterward to penetrate properly. If you’ve tried everything and still truly feel like your skin prefers a bar cleanser, just make sure you’re rinsing your face really thoroughly after cleansing to get as much residue off as possible.
Celebrity Esthetician & Skincare Expert
As an esthetician trained in cosmetic chemistry, Renée Rouleau has spent 30 years researching skin, educating her audience, and building an award-winning line of products. Trusted by celebrities, editors, bloggers, and skincare obsessives around the globe, her vast real-world knowledge and constant research are why Marie Claire calls her “the most passionate skin practitioner we know.”