What evidence convinces you that products need to be pH balanced?

PerryPerry Administrator, Professional Chemist
edited July 2019 in Science
This is a good read about pH and the science (or lack thereof) used to support claims made about it.


What does pH balanced mean to you?  And why do you think it matters?

Certainly, it matters in terms of the effectiveness of a preservative system or a hair chemical treatment, but for shampoos and skin lotions, there's not much scientific evidence - at least that I know.  How about you?


  • PharmaPharma Member, Pharmacist
    Having an intact "acid mantle" i.e. slightly acidic pH on the skin helps reducing microbial growth. Absence of an acid mantle is allegedly (I say allegedly because I haven't read anything useful since I can't read everything) linked to increased (infection related) skin disorders.
    On the other hand, we're in the era of probiotics and talk also about skin microbial flora... as it seems, an intact microbial flora (not just on the skin, but everywhere where we have microbes) is a more effective protection from "bad" microbes. A lower pH allows for the growth of lactobacilli and these are often the "good" guys -> a low pH would go well together with the skin microbiome hypothesis.

    BTW "balanced pH" is a stupid marketing term and means nothing.
  • JonahRayJonahRay Member
    edited July 2019
    I've read a lot about this but more in terms of skin cleansing. What I read was that after cleansing with bar soap for instance it requires quite a long time to return to optimal pH which leaves the skin in a more compromised state for longer. My reason for researching this was to see if using a more acidic toner is an effective way of rebalancing the skins pH allowing for quicker recoup after cleansing.

    My thoughts when choosing a pH is that it really needs to be one that is compatible with the ingredients, especially the preservative system. We use exfoliating acids on our skin which certainly are not at skin pH so why should it matter. 

    My understanding is the skin is very capable of re-acidifying after applying a cream that may be more basic for instance.
    Cosmetic Product Development
    Sussex Research Laboratories Inc.
  • Does 'balanced pH' have any exact definition?

    "Optimized pH" works great in my opinion:
    Slightly acidic pH (5-6) for skin mildness
    a bit more acidic (4-5) for smooth hair
    and about neutral pH to reduce eye irritation.
  • Great article, have done similar research myself. One interesting point though, and this is really old science (that's because Im a really old guy).... soap, body wash etc is designed to clean, and cleaning chemistry occurs better in a more acid than neutral or basic environment.
    Dr. Mike Thair
    Cofounder & Chief Formulator
    Indochine Natural
  • PharmaPharma Member, Pharmacist
    @Perry: Just stumbled upon the book "Handbook of Cosmetic Science and Technology" by Barel, Paye and Maibach.
    Chapter 20 and 21 are about skin pH.
  • DASDAS Member
    Nice topic. My evidence is observation. Double blind tests and consumers feedback. The most important thing I learned is pH should be balanced, although not just taking in consideration the skin, but how's applied, for how long and how often, and more important, the materials being used. Surfactants will change dramatically their mechanism of action under different pH. Specially anionics. Actually, now that I think about it, I didn't learn much. Just that making a little pH adjustment will come a long way on sensitive skin if harsh materials are being used. 

    Regarding this it's interesting to observe the behaviour of big companies. For example Dove doesn't care much regarding the pH of baby products. Or more precisely, they make a perfectly safe alkaline liquid soap, completely disregarding skin flora and new trends. 

    As the article says we need better science, and I dare to say that science exists, it's just not available. One of the hardest things when formulating is to achieve the best performance with the lowest cost. I doubt companies that invested millions on research would allow data to go public. 
  • SpongeSponge Member
    DAS said:
    I doubt companies that invested millions on research would allow data to go public. 
    This is probably the most unfortunate part of the industry, coming from medicine. 
  • DtdangDtdang Member
    @Perry, @DAS, @Sponge, @Gunther, @Pharma
    1) pH of human skin = [4, 6.5], optimization of 5.5 ?
    2) Is it good to have facial cream pH to be in the range of 4 to 6.5 ? 
    3) Ascorbic acid is good effect with pH of less than 4?
    4) Retinol is good effect with pH of greater than 6?
    5) Ascorbic & retinol cannot work together?

  • PharmaPharma Member, Pharmacist
    1) Skin pH isn't fixed and depends on a lot of factors including under others ethnics, climate/season, age, test method/lab, tested area (face, extremities etc.). Whether or not it needs to be slightly acidic is not fully understood though sebum composition points towards a naturally acidic pH.
    2) Your skin will tell you within a few days of regular usage.
    3) Depends on which effect you're referring to.
    4) AFAIK not regarding product stability. Effect-wise it doesn't matter as long as retinol penetrates deep enough.
    5) Again, depends on the effect you're hoping for.
  • DtdangDtdang Member
    @Pharma, thanks for answering 
    1) the pH of the skin is in the range between 4 to 6.5 and it depends on as you mentioned. So the facial cream must be in that range?
    2) can you explain more details?
    3) ascorbic acid is working on fading dark spots 
    4) retinol for stimulating new cells

  • PharmaPharma Member, Pharmacist
    edited July 2019
    1) Who says it has to be in that range? It seems as a logic deduction but there's enough evidence that there is no "must be".
    2) You'll get for example pimples, rashes, or itchy skin if your cream is out of the "healthy" limits.
    3) Fading like bleaching or like reduced pigment formation? pH will affect ascorbic acid stability and reactivity and hence its antioxidative efficacy. But this is during storage. Once it penetrates skin it will depend on skin pH. Skin pH in this case is not on the skin sebum pH but the pH in the corresponding skin layer. Changing that one isn't just dependent on pH of an applied product but also (or even more so) the quantity of pH active substances and composition such as compounds which change pH between and/or within living cells due to mechanisms other than their inherent acidity/alkalinity.
    4) Living cells are self-regulating and the intracellular pH will always be the same. Therefore, pH of a preparation doesn't directly affect the effect of retinol (which, assuming it's metabolised to retinoic acid, acts as nuclear factor) but pH and the whole composition of a product might interfere with pharmacological activities of retinol/retinoic acid by different means. There is no simple answer and it's not just about high or low pH.
  • DtdangDtdang Member
    @Pharma what is the healthy limit?f
  • PharmaPharma Member, Pharmacist
    That's what your skin will tell you! There is no "in the books" limit (well, probably below 2 and above 12 :) ).
  • DtdangDtdang Member
    @Pharma thanks for your kindness.

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