Home Cosmetic Science Talk Formulating General Is TEWL the only reason for dry skin?

  • Is TEWL the only reason for dry skin?

    Posted by DaveStone on December 24, 2021 at 6:00 am

    I was thinking before about my own skin…maybe it’s dry because my skin doesn’t produce enough sebum. Is there any ingredient that can increase its production? Or should I just look to include things like cholesterol or ceramides to supplement the skin’s natural lipids?

    Syl replied 2 years, 3 months ago 9 Members · 23 Replies
  • 23 Replies
  • Abdullah

    Member
    December 24, 2021 at 7:45 am

    Use low pH products to increase sebum production

  • Abdullah

    Member
    December 24, 2021 at 7:46 am

    pH below 4

  • suswang8

    Member
    December 25, 2021 at 3:19 am

    @Abdullah, where is the evidence to support using low pH products for that?

  • Abdullah

    Member
    December 25, 2021 at 9:40 am

    suswang8 said:

    @Abdullah, where is the evidence to support using low pH products for that?

    Currently my own experience. 

    make a low pH solution without adding any other ingredients. Only water and lactic acid or citric acid or vinegar or whatever way that you can reduce the pH and use it on your face and see how much oil will your face produce.

    High pH for dry skin. Just increase the pH of water with sodium hydroxide or soda or anything else and it will make your skin dry as hell.

    That is why i make my products at low pH. The ingredients may or may not benefit the dry skin but it will definitely stimulate your skin to produce more oil. 

  • DaveStone

    Member
    December 25, 2021 at 12:13 pm

    Abdullah said:

    suswang8 said:

    @Abdullah, where is the evidence to support using low pH products for that?

    Currently my own experience. 

    make a low pH solution without adding any other ingredients. Only water and lactic acid or citric acid or vinegar or whatever way that you can reduce the pH and use it on your face and see how much oil will your face produce.

    High pH for dry skin. Just increase the pH of water with sodium hydroxide or soda or anything else and it will make your skin dry as hell.

    That is why i make my products at low pH. The ingredients may or may not benefit the dry skin but it will definitely stimulate your skin to produce more oil. 

    It’s hard to do that as some of the ingredients I incorporate are more stable around PH 6 (niacinimide, urea).

  • Paprik

    Member
    December 25, 2021 at 8:25 pm

    Niacinamide handles lower pH. (3.5 - 7.5)

  • Graillotion

    Member
    December 25, 2021 at 9:21 pm

    Paprik said:

    Niacinamide handles lower pH. (3.5 - 7.5)

    Correct….that was just repeating mommy blogger lore (sometime mommy bloggers go to the next level…and become…..repackers…hehehe) ….no (applicable) science.  Mine all goes in at 4.8 pH.  And the word ‘stable’ was misused. :) 

    (That lore came from an old study….high heat….1000 days….and a strong acid.  It is what happens when they read scientific papers…and don’t understand them…..and then they just all repeat what the ignorant one said.)

  • zetein

    Member
    December 25, 2021 at 11:11 pm

    You need exfoliation. Exfoliation is King.

  • DaveStone

    Member
    December 26, 2021 at 6:50 am

    Paprik said:

    Niacinamide handles lower pH. (3.5 - 7.5)

    Correct….that was just repeating mommy blogger lore (sometime mommy bloggers go to the next level…and become…..repackers…hehehe) ….no (applicable) science.  Mine all goes in at 4.8 pH.  And the word ‘stable’ was misused. :) 

    (That lore came from an old study….high heat….1000 days….and a strong acid.  It is what happens when they read scientific papers…and don’t understand them…..and then they just all repeat what the ignorant one said.)

    But how could you tell if the niacinimide degraded or not? I was more concerned with the urea anyhow.

  • DaveStone

    Member
    December 26, 2021 at 6:52 am

    zetein said:

    You need exfoliation. Exfoliation is King.

    I never understood why soap/surfactants can’t do this. Aren’t they supposed to remove dirt, oil, and dead skin cells?

  • DaveStone

    Member
    December 26, 2021 at 7:44 am
    When you apply this citric acid solution to your face, do you wash it off after a certain time, or does it self-neutralize when your skin returns to its original PH after an hour or so? Wouldn’t it technically be an AHA then?
  • Abdullah

    Member
    December 26, 2021 at 10:42 am

    I am currently using lactic acid at pH 2.5. although it is currently for own use and not on sell. 

    No i dont wash it. 

    I have seen a patent by p&g that used niacinamide at pH 2.5. so i think niacinamide is stable at up to pH 2.5.

  • vitalys

    Member
    December 27, 2021 at 6:15 pm

    TEWL cannot be a reason, it is a result and one of the functional indicators. There are three pools/reserves of water in the skin - blood supply, dermal water, epidermal water. All of them are associated and dependent on each other. 

  • Chembi

    Member
    December 31, 2021 at 8:29 am

    I’m manufacturing soap from noodles. Some customers complained that it’s too drying and gives them pimples. Could this be due to higher pH? What can we do to say lower the pH by about one unit?

  • Abdullah

    Member
    December 31, 2021 at 11:05 am

    Yes it is because of pH. 

    What is your current pH?

  • Syl

    Member
    December 31, 2021 at 12:23 pm

    @Chembi, what kind of noodles are you using? A high percentage of coconut noodles will make your soap very drying. I do not believe you can change the PH of your soap unless you make syndet bars. 

  • Chembi

    Member
    January 3, 2022 at 3:58 am

    Will incorporation of citric acid not help?

  • Chembi

    Member
    January 3, 2022 at 4:06 am

    My noodles have the following specs:
    80:20 Palm and Palm kernel
    PH 10

    TOTAL FATTY MATTER, % 78 – 81
    MOISTURE, % 13 – 15
    FREE FATTY ACID, % 1.5 MAX
    CHLORIDE CONTENT AS NaCI, % 0.4 MIN
    GLYCERINE, % 1.0 MAX
    PRESERVATIVE* EDTA 0.5 and EHPA 0.2%
    We incorporate kaolin as a filler.
  • Abdullah

    Member
    January 3, 2022 at 7:08 am

    pH 10 and above are very drying

  • Syl

    Member
    January 3, 2022 at 2:42 pm

    When you make soap adding citric acid converts NaOH into sodium citrate which is a chelating agent, it does not affect the PH which remains around 9-10.
    I believe the same thing happens if you add citric acid to soap, fatty acid will be released and the PH will be unchanged. This link explains it very well: https://www.ultimatehpsoap.com/post/soapy-science-citric-acid-in-soap-making
    To make your soap milder; I would test increasing the glycerin concentration, 
    and increasing free fatty acids (if possible).
    When making soap from scratch with fat and NaOH we usually aim for a minimum of 5% free fatty acids, this improves mildness, otherwise your formulation is balanced.

  • Syl

    Member
    January 3, 2022 at 3:12 pm

    Actually, if I were you, I would try to use sodium citrate instead of EDTA as my chelator this will also free some fatty acid to make your soap milder.
    Not sure how this can be adapted to your manufacturing process, I imagine citric acid would have to be dissolved in water first. You may want to verify the feasibility by reading the ingredients of other popular soap manufacturers. 

  • Chembi

    Member
    January 9, 2022 at 2:56 pm

    Thanks for useful comments. I use the noodles that are already manufactured and they have specs as stated above. So they already have EDTA. Was thinking citric acid will mop up any free alkali that may be responsible for higher pH. Now you also reminded me of another dimension that it will also release free fatty acids. I add a little Shea butter at 0.8% to the noodles to try super fat. What do you think? Should I increase the Shea butter?

  • Syl

    Member
    January 9, 2022 at 3:45 pm

    Increasing super fat will make your bars milder, but at too high concentration it will affect foam.
    I would make small batches and test different concentrations. Most soap calculators (alkali/fat ratio calculators) use 5% fatty acid/super fat as the default setting. That is what I use in my soaps, and they are considered mild. I still find syndet bars to be less drying.

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