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Is soap bad for skin?


Anne says…Real soap is NOT problematic for all people, either on skin or on hair. Many just don’t like the feeling on hair, but if you happen to, just use shampoo every few washes to prevent buildup. And as for skin, many people have zero problem with a high pH wash off product. For those who do, there are other options yes. Sad to see this answer jump onto the bandwagon of disregarding soap without a full answer, and it just isn’t the whole truth to say that “Regular soap is not good for skin”.

The Beauty Brains respond: 

Anne’s comment comes to us from our recent post on using bar soap on hair. I agree that my original answer wasn’t detailed enough so I’ll try to correct that here.

I certainly don’t blame Anne for defending bar soap since she’s affiliated with Dot & Lil, a company which sells vegetable oil based soaps. But it’s well documented that soap is more drying to skin than surfactants. In fact, plain old ivory soap is used to dry out skin in moisturization testing!

Soaps and synthetic surfactants can dry skin

Of course that’s not to say that surfactants are perfect and that they do no harm. Anything which solubilizes oils has the potential for stripping the skin. Some surfactants, like sodium lauryl sulfate, don’t rinse well because they can interact with skin protein. The residue they leave behind is irritating so some people.

BUT, surfactants (which typically have a pH in the range of 5-7) do not upset the skin’s acid mantle as much soap which has a pH in the range of 9-10. If the mantle is washed away or neutralized by alkaline agents then the skin is more easily damaged or infected. That’s because, without the mantle, the skin cells start to separate and allow more moisture loss which in turn causes tiny cracks in the skin where bacteria can enter.  Once the mantle is depleted and the pH of skin gets above 6.5 you’re much more prone to damage and infection.

There are number of studies such (see below) that have evaluated the harshness of cleansers and have consistently found that soap is worse than surfactants.

The Beauty Brains bottom line

All cleansers have the potential to strip oils from your skin but soap has been shown to be more drying, harsher, and more disruptive to the skin’s protective acid mantle than many surfactants.

References

Interactions of cleansing bars with stratum corneum proteins
Journal of the Society of Cosmetic Chemistry 46, 301-320 November/December 1995)

Forearm wash test to evaluate the clinical mildness of cleansing products
Journal of the Society of Cosmetic Chemistry 39, 355-366 (November/December 1988)

Soap and detergent bar rinsability
Journal of the Society of Cosmetic Chemistry 37, 89-97 (March/April 1986)

{ 29 comments… add one }
  • Eileen May 12, 2014, 11:42 am

    Soap recipes have been found that date back more than 4,200 years, but just because they worked for the ancient Babylonians, it doesn’t mean that they are what we should be using today. Over the millennia, those ancient soap formulas evolved as people sought to create a better product that was easy to use, convenient to store, pleasing to the senses, and that would do the job of thoroughly cleansing without being harsh and drying. Eventually, we arrive at today’s bar soaps which are much less harsh than the primitive soaps of yore or even the ones of the past few decades, but they definitely aren’t the gentlest, most skin/hair friendly products around. That’s been proven time and time again in the lab and, if store shelves are any indication, most consumers are showing a strong preference for other skin cleansers over bar soap. The way I see it, abandoning bar soap in favor of other surfactants is just another step in the evolution of cleansers as we search for a better means of caring for our skin and hair.

  • Laurie Brown May 12, 2014, 11:54 am

    I like to use a true soap on my face, *but* my face and neck are very oily. It works perfectly for me, whereas if I use a syndet my face is shiny in no time and my makeup doesn’t stay put nearly as well. I suspect the soap/syndet thing is a case of YMMV.

  • Pedro May 12, 2014, 1:32 pm

    Out of curious, in Japan a facial cleanser that isn’t soap based (in fact, they usually are mixture of synthetic surfactants and soap) wouldn’t sell almost any there. Due to cultural reasons a facial cleanser there must make an extremely dense and huge foam – something impossible to achieve just with synthetic surfactants). Some companies even disclosure the density of the foam in microns. LOL On the other hand, they also usually contain a lot of anti-drying ingredients and people use them without to put almost any pressure during the massage with the foam. The foam is made on the hands and then applied very gently on the facial skin. I think it helps…

  • Jtest11 May 13, 2014, 2:44 am

    Interesting, been recently looking for the perfect price/performance bar or body wash.

    Most bars dry me out like crazy (especially Dove for some reason) and most washes leave an annoying film. Recently stumbled upon Old Spice’s body washes and they seem to be the only wash I can find that are simple cleansers:

    Water, Sodium Laureth Sulfate, Sodium Chloride, Sodium Lauryl Sulfate, Fragrance, Cocamidopropyl Betaine, Sodium Benzoate, Citric Acid, Disodium EDTA, Methylchloroisothiazolinone, Methylisothiazolinone, Potassium Sorbate, Yellow 5, Red 33

    Thinking I’m just gonna stick with them as a body wash/shampoo and use another moisturizer post-shower.

  • Anne May 13, 2014, 9:06 am

    Thank you for the response to my comment Perry! This is a much fuller picture. I always make sure to tell people to stick with syndets if that is what works for them. The thing is, most people do not distinguish between the two in bar form, and even more so with bars that have a mix of true soap AND syndets. Understandably it is a confusing distinction for most consumers! Add to that that handmade and handcrafted bars are not at all like most commercial bars, and it gets even more blurred. The fact that many handmade soaps are superfatted, etc. means they are unlikely to perform like the ones you have presented research for. Though again, there will ALWAYS be people who do better with a low PH syndet bar, and also those who do best to avoid foaming cleansers of all kinds, true soap or not. As a manufacturer of both bar soaps and other skincare items I spend a lot of time thinking and talking about this of course, and mainly I just think people need the correct info to make a decision. It just gets under my skin (ha!) to see bar soap presented as a non-option–and lest we forget, not all bar soap is created equal! Thanks for taking the time to present this well, I am happy to read it!

    Best,

    Anne

  • Natasha May 13, 2014, 11:13 am

    I just read the 1988 study, as a chemist myself, I found the procedure very well thought but the formulation of the soaps are not comparable (with and without synthetic surfactants), there is not a test with the same formulation (Tallow/coconut oil) with and without surfactant. It is well know that coconut oil soap is very dryer to the skin, so I was not surprised by the results, that is why it is not recommend to use over a 30% of it in a handcrafted soap. I would agree with Anne in this, not all the soaps are made equal and for someone that is looking for a real soap (with not surfactants added and glycerol still on it) a well formulated handcrafted soap could be a good alternative. Also I would not consider this paper coming from Procter and Gamble an “independent study”. Just my two cents.

  • Rachel July 7, 2014, 10:42 am

    Does tea work to cleanse hair?

    • Randy Schueller July 7, 2014, 7:27 pm

      No. (Other than the fact that tea is dissolved in water and water will rinse way dirt.)

  • Kaylee Jayne March 5, 2015, 5:21 pm

    Hi there,

    I totally understand the science of this (the pH, the acid mantle, etc.), but I’m one of those people that has skin success with a higher-pH true soap. What would be the scientific reasoning behind people like me? I’ve been searching the internet but I can’t find an answer. I thought maybe you guys would know.

    Thanks,
    Kaylee

    • Randy Schueller March 5, 2015, 8:12 pm

      Hi Kaylee. It’s hard to say why you like “true” soap so much. What else have you tried? (For example, have you used the syndet bars we talked about based on SCI? Or body washes based on mild surfactants?) And, what kind of “skin success” have you had? (Cleaner feeling skin? Fewer breakouts? Less dryness? etc etc.)

      • Kaylee Jayne March 11, 2015, 11:35 am

        Hi Randy! I’ve tried Dove body wash, and Bath and Body Works body wash, and some other random things I’d pick up at the store (but we usually have the Dove Deep Moisture something-or-other in the shower, because it’s what my husband likes). When I use it, I usually feel dry (my legs get extra flakey) but also slimy (mostly on my back) at the same time, in a way that I don’t feel when I’m using a bar of the old timey stuff. I guess I just don’t get dry with soap in a way that I’d expect. Could it be our soft water?

        As for my face (which I consider a completely different animal), I like a “milky” kind of cleanser (smooth skin, no breakouts, no dryness), but pH tested over an 8 (maybe even close to a 9!). I thought I probably shouldn’t use it anymore because of the pH and I recently tried a mildly acidic cleanser but broke out on my temples and nose, got uneven skin tone, and really dry skin around my mouth. I stuck with it for two weeks, then gave up. (I also tried the oil cleansing method with even worse pimples.)

        I guess my ultimate question is, should I stop using these products because of the high pH? After the additional reading I’ve done on the internet in the last couple of days, it sounds like I’m irreparably damaging my skin and even though it feels and looks fine now, I’ll wake up one day with terrible wrinkles and spots and get infections. What should I do?

        Kaylee

      • Kaylee March 11, 2015, 11:51 am

        PS: I just found the ingredients for the Dove my husband uses — it has SLS in it, not SCI. So now I’m not sure if I’ve tried an SCI body wash. Maybe I should look for one of those to try.

        • Randy Schueller March 11, 2015, 12:50 pm

          Yes, looking for and SCI product sounds like a good next step. The pH won’t be so high either.

          • Kaylee Jayne March 11, 2015, 1:00 pm

            Sounds like a plan!

            How about for my face? The cleanser I like is SLS-free. Can I keep using it even though it’s not acidic?

            Thank goodness for this website! I was really falling down the rabbit hole out there.

          • Randy Schueller March 11, 2015, 4:41 pm

            Can you send me a link to the product’s ingredient list?

          • Kaylee Jayne March 11, 2015, 5:08 pm
          • Randy Schueller March 11, 2015, 5:16 pm

            This looks like a fairly standard emulsion type oil cleanser. Are you telling me that the pH of this product is almost 9? Are you sure about that measurement? That result seems really strange because this kind of emulsion system is typical closer to a neutral pH of 7-ish.

            BTW, here are the ingredients for anyone who’s interested:
            Aloe Barbadensis Leaf Juice(1), Aqua (Water), Stearic Acid, Glycerin, Glyceryl Stearate SE, Cetearyl Alcohol, Cetyl Alcohol, Caprylic/ Capric Triglyceride, Helianthus Annuus (Sunflower) Seed Oil(1), Aleurites Moluccana Seed Oil, Borago Officinalis Seed Oil(1), Butyrospermum Parkii (Shea Butter)(1), Citrus Aurantium Bergamia (Bergamot) Fruit Oil, Citrus Aurantium Dulcis (Orange) Peel Oil, Citrus Limon (Lemon) Peel Oil, Hydrogenated Palm Kernel Oil, Arnica Montana Flower Extract(1), Camellia Sinensis Leaf Extract(1), Chamomilla Recutita (Matricaria) Flower Extract(1), Citrus Limon (Lemon) Peel Extract*, Laminaria Digitata Extract(1), Lavandula Angustifolia (Lavender) Flower/Leaf/Stem Extract(1), Linum Usitatissimum (Linseed) Seed Extract(1), Olea Europaea (Olive) Leaf Extract(1), Ascorbic Acid, Ascorbyl Glucoside, Cetearyl Glucoside, Potassium Hydroxide, Tocopheryl Acetate, Xanthan Gum, Alcohol(1) , Benzyl Alcohol, Potassium Sorbate, Sodium Benzoate, Limonene

          • Kaylee Jayne March 11, 2015, 5:36 pm

            Hmm. Maybe because I tested it with water? (I tested the my hands when I washing my face.) The green just looked a littler darker than the “8” to me.

            Anyway, I can keep using it, yes? 🙂

          • Randy Schueller March 12, 2015, 6:38 am

            If you like the way it makes your skin feel then it should be fine.

  • Kathleen July 13, 2015, 8:22 am

    I have had acne, black heads and just aweful skin for the last 30 years. I tried all those PH balanced cleaners, all the acne care thingies, but nothing changed it. I switched to a bentonite clay natural soap bar, and POOF, it all went away! After 30 years of yucky and low self estime, I feel good about myself, and I will never switch back.

  • Elsa July 30, 2015, 11:29 pm

    Truly Natural soaps are not bad for your skin , as someone who has been using only soap on there skin all there life i can tell you soaps that contain nasty chemicals such as SLS and Alcohols are bad for your skin and they overly strip skin of important oils. As an eczema suffer i was looking for a solution to my skin problems and i did not want to give up my soap bar, after doing some research i came across a company called beauty and the bees http://www.beebeauty.com/ who make soaps 100 % chemical free and boy let me tell you don’t give up on soap until you try a natural soap bar the one i used from beauty and the bees was called Dead sea mud and leather wood honey it cured my ezcema and makes my skin smooth and even helped reduce my fine lines!! and just remember one last thing no real soap can not be made without lye and i know that word can seem scary but no lye remains in the final product so you have nothing to worry about.

    • Randy Schueller July 31, 2015, 7:26 am

      So how do you explain the scientific data that shows the higher pH of soap causes the natural acid mantle of the skin to take longer to recover?

  • Julia February 28, 2017, 1:46 pm

    Hi,
    I’m also one of the sucessful soap users and also wonder why it works so well even if it’s supposed to dry out your skin. I’m especially surprised because after washing my hair with soap (mosty babassuoil, sheabutter, avocadooil and natron in these) I don’t need to wash it for about 4 days and it doesn’t itches while I got dandruff and itching from most shampoos and my hair gets greasy after one to two days after every shampoo I’ve tried. Isn’t it supposed to be the way that if your hair gets greasy faster you’re using something that dries your skin more so the skin tries to moisturise itself or did I get something wrong?

  • Melissa April 16, 2018, 8:15 pm

    I make my own soap and have never ph tested any of them. It never really occurred to me that I would have a problem. And I don’t. My skin has never been happier than using my homemade soap and some jojoba oil. Fewer breakouts, more moisturized skin. I don’t have anything that isn’t healing because of a damaged acid mantle. All my family wants soap all the time because their skin does well with it too. I do have problems with really dry, tight skin though, when I do use a body wash. I’m sure it’s just a matter of preference.

  • Conrad Zimmerman January 1, 2019, 11:27 pm

    Here are some more referenced studies showing these same conclusions I have copied and pasted this here from another website. “Many factors, such as age, ethnic differences, sebum, sweat, detergents, cosmetics, and irritation, affect the pH of the skin” (Takagi, Y., et. al. [2014], The Long-Term Use of Soap Does Not Affect the pH-Maintenance Mechanism of Human Skin. Skin Research and Technology, 0: 1).

    Cleansing surfactants, such as soap (from 9.5 to 11 pH) and synthetic detergent bars (“syndets”) (from 3.6 to 7.5 pH), and even water alone (usually about 7 pH) also affect the pH of the skin and alkanize it (Sources: Takagi, Y., et. al. [2014], The Long-Term Use of Soap Does Not Affect the pH-Maintenance Mechanism of Human Skin. Skin Research and Technology, 0: 1; and Abbas, S., Goldberg, J.W. and Massaro, M. [2004], Personal Cleanser Technology and Clinical Performance. Dermatologic Therapy, 17: 36-38; and Draelos, Z. [1998], Cosmetics, Skin Care Products, and the Dermatologic Surgeon. Dermatologic Surgery, 24: 543).

    Specifically, “skin pH rises 1.1 points following washing with water alone, 1.2 points after washing with alkaline soap, and 0.9 points after washing with a synthetic detergent beauty bar” (Draelos, Z. [1998], Cosmetics, Skin Care Products, and the Dermatologic Surgeon. Dermatologic Surgery, 24: 543; see also Takagi, Y., et. al. [2014], The Long-Term Use of Soap Does Not Affect the pH-Maintenance Mechanism of Human Skin. Skin Research and Technology, 0: 1).

    The pH of the skin, however, is maintained by the “acid mantle,” and due to the mechanisms of the acid mantle, “the pH of the skin normally returns to an acidic pH even when changed by [outside] factors” (Takagi, Y., et. al. [2014], The Long-Term Use of Soap Does Not Affect the pH-Maintenance Mechanism of Human Skin. Skin Research and Technology, 0: 1).

    Indeed, the pH of healthy skin returns to normal “within 30 minutes after washing” (Draelos, Z. [1998], Cosmetics, Skin Care Products, and the Dermatologic Surgeon. Dermatologic Surgery, 24: 543-546).

    Alkalinity only becomes a problem if the skin pH remains elevated for more than 4 hours because of insufficient rinsing and/or too frequent product use (Source: Abbas, S., Goldberg, J.W. and Massaro, M. [2004], Personal Cleanser Technology and Clinical Performance. Dermatologic Therapy, 17: 36).

    On April 1, 2011, Dr. Zoe Diana Draelos, a consulting professor of dermatology at Duke University School of Medicine, wrote an article for the Dermatology Times. In the article, available at (http://dermatologytimes.modernmedic…ow/do-ph-balanced-vitamin-d-products-really-i), she answered the question, “Are pH-balanced skincare products better?” Dr. Draelos wrote that “[t]he concept of pH-balanced products was introduced many years ago as an effective marketing strategy for soaps and moisturizers” and noted that there was “some merit” to the concept that products formulated around a pH of 5 to 5.5 may not cause stinging or burning when applied to sensitive, diseased or injured skin.” An even newer concept in US skincare is that slightly acidic products, formulated at a pH of 4, are even better in maintaining the acid mantle of the skin, in that keeping the skin at a slightly acidic pH can minimize bacterial colonization of the skin by normal organisms and pathogenic organisms. Dr. Draelos concluded, “It is important to remember that healthy skin will regain its acid mantle within 15 to 30 minutes after application of a skincare product, depending on pH. Retaining the acid mantel is only problematic in compromised barrier conditions.”

    Citing Dr. Draelos, Randy Schueller and Perry Romanowski, cosmetic chemists at TheBeautyBrains.com, wrote in their 2013 book, It’s Okay to Have Lead in Your Lipstick: “We’ve always maintained that pH balanced skin care products are just marketing hype, because the skin’s natural pH resets itself within as little as 15 minutes after applying lotion…. So while we’re in full agreement with the expert assessment that in some special circumstances the pH of the product can make a difference, we maintain our stance that in the general case, pH balance is more hyperbole than healthy. The Bottom Line: Unless you have a skin disease, you don’t need to waste your money on products that expect you to pay more just because of their pH.”

    Further, in discussing facial cleansers versus “true” soaps on the face, Cindy Jones, Ph.D. a cosmetic formulator and microbiologist, wrote on the website PersonalCareTruth.com (http://personalcaretruth.com/2010/06/ask-the-experts-5/) that while washing with true soap will “somewhat” disrupt the normal pH of the skin, as compared to washing with a syndet, healthy skin will return to normal and that the return can be “hastened” by following washing with a slightly acidic toner or applying a lotion or cream, which are in the range of 3 to 6 pH, matching the pH of the skin.

    A study published in 2014 (Takagi, Y., et. al. [2014], The Long-Term Use of Soap Does Not Affect the pH-Maintenance Mechanism of Human Skin. Skin Research and Technology, 0: 1-5) addressed the allegation that the continuous usage of a soap or an alkaline skin cleanser might increase the pH of the skin by affecting the system that maintains its pH. To clarify the effects of continuously-used cleansers on the pH of the skin, the study compared skin surface pH prior to and following washing with a soap bar between 5-year-long users of a soap-based cleanser and of a mild-acidic cleanser. The study concluded that long-term continuous use of an alkaline soap-based cleanser does not affect the mechanisms of the acid mantle in maintaining a mildly acidic pH of the skin. Furthermore, the paper noted that “[d]uring regular use of soap, the contact time of the surfactant to the skin is very short and is followed by rinsing with water. [The data] may suggest that the penetration of soap during regular use has less effect and the buffer capacity of the stratum corneum [i.e., the outermost layer of the epidermis] far exceeds the amount of acid necessary to transform residues of the surfactant” on the skin (Takagi, Y., et. al. [2014], The Long-Term Use of Soap Does Not Affect the pH-Maintenance Mechanism of Human Skin. Skin Research and Technology, 0: 4).

    I think it is those with severely dry skins, or those with a compromised skin are really the only people who should avoid or reduce the use of soap. Those with a healthy skin barrier, have the whole soap sud world to choose from however I believe when it comes to being gentle as much as possible, surfactant body washes/liquid or Sydney bars/cleansers will always be less harsh and drying than soap. Experimentation is necessary!

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