The Update
Well, I feel really beat down by what I’ve found out in my research and in my internet searches this past week. It looks like people are convinced that soap is bad, it’s incredibly easy to back it up with the pH studies out there, and there’s no perfect science to back up our positive anecdotal experiences. Here’s what I’ve got…
The surface of healthy adult human skin across the body ranges from 4.0 pH to 5.9 pH (Source: Korting, H. and Braun-Falco, O. [1996], The Effect of Detergents on Skin pH and Its Consequences. Clinics in Dermatology, 14:23-27).
“The acidic pH inhibits some bacterial and fungal growth” (Draelos, Z. [1998], Cosmetics, Skin Care Products, and the Dermatologic Surgeon. Dermatologic Surgery, 24: 543-546).
“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).
Studies acknowledge that “
uperfatting [true soap] improves the moisturization and mildness of the product, as well as the lather, mush, and wear properties” (Abbas, S., Goldberg, J.W. and Massaro, M. [2004], Personal Cleanser Technology and Clinical Performance. Dermatologic Therapy, 17: 36).
Indeed, “modern cleansing bars, even soap bars, are nowadays very complex mixtures that are generally very mild on the skin. The potential irritancy of the alkaline surfactants present in the soap cleansing bar are neutralized by the addition of humectants, filmogen, and emollient ingredients” (Barel, A.O., et. al. [2001], A Comparative Study of the Effects on the Skin of classical Bar Soap and a Syndet Cleansing Bar in Normal Use Conditions and in the Soap Chamber Test. Skin Research and Technology, 7: 98-104).
As for syndets, they “vary widely in terms of their chemical structure, physiochemical properties, and performance characteristics, including skin compatibility. Syndets are not necessarily less irritating than soaps” (Cosmetic Dermatology: Products and Procedures, edited by Draelos, Z. [2010]).
Interestingly, while one study comparing the pH of products to their “irritation potential” confirmed that sydents are generally “milder” than “common soaps,” it also illustrated the difficulty in taking a rigid approach to pH. The data revealed that the least irritating sydent (0.200) was Dove White, with a pH of 7.53, whereas the most irritating syndet (3.333) was Avecycle, with a pH of 3.61. Meanwhile, the least irritating soap (2.779) was Johnson’s Baby Oat, which had a pH of 12.35, whereas the most irritating soap (5.284) was Camay Gala, with a pH of 10.36. (Source: Abbas, S., Goldberg, J.W. and Massaro, M. [2004], Personal Cleanser Technology and Clinical Performance. Dermatologic Therapy, 17: 36-38 ).
In sum, for those with healthy skin, data points to “true” soap not being "inherently bad." The choice of what to use as a cleanser may be left to personal preference. Even Randy Schueller, cosmetic chemist at TheBeautyBrains.com (who, from all evidence, seems to loooooooove syndets), appears to agree that “everyone’s skin and preferences are different. Personal experimentation is your best option” (http://thebeautybrains.com/2008/11/17/what-is-the-difference-between-soap-surfactants/).
WHEW! Many thanks to all of you, who pointed me in some wonderful directions for this research! 
