Home Cosmetic Science Talk General Help me make sense of this: effective and compatible over a pH range of 3 – 8.

  • Help me make sense of this: effective and compatible over a pH range of 3 – 8.

    Posted by graillotion on May 11, 2023 at 8:25 pm

    As you know…I help out on beginner forums. Where preservative selection is done by polling other beginners. So here is the INCI of one they love to flock to:

    Benzyl Alcohol (and) Salicylic Acid (and) Glycerin (and) Sorbic Acid

    So… I see an alcohol…and two acids. All is somewhat good to this point. But …. What about that title… Mfg says this magic elixer works at a pH range up to 8! Now memba…most of these folks that have flocked to this, have never heard of a chelate….and they have piled more bug food into the formula than a F-bomb plus parabens could handle. That … and the pH…is just gonna be native. Heck…what good would adding lactic acid do? 😂

    So can one of you chemistry whiz’s tell me how those last two ingredients are gonna help when the pH gets much above 6?

    I suspect the ‘eager to sell product’ mfg…is of the attitude…that JUST the Benzyl alcohol will carry the load in the 6-8 pH window? Am I wrong? Will these neutralized acids…have some magic residual activity I am just to dull to understand?

    The mommies and I…look forward to your answer.

    • This discussion was modified 6 months, 3 weeks ago by  Graillotion.
    philgeis replied 6 months, 1 week ago 5 Members · 14 Replies
  • 14 Replies
  • graillotion

    May 11, 2023 at 8:31 pm
  • graillotion

    May 11, 2023 at 8:36 pm

    BTW… I do not use this as a preservation system…just trying to help those that do. 🙂

  • gordof

    May 12, 2023 at 3:48 am

    well. Most of the effectiveness at a ph between 7-8 comes from the benzyl Alcohol.

    The Sorbic Acid will lose its effectiveness around a ph of 7 before that point around a ph of 6 10-20 % of the Sorbic acid will be in acid form and therefore still active. at a ph of 4.5, it would be 80 %

    For the Salicylic Acid, it is similar I think if I remember correctly the active point for the neutralization of Salicylic acid is around 6.5 . above that, the active concentration will be very low.

    I guess the idea of the Product is depending on the Product you want to use one of the two will be active and therefore eliminate the bacteria and Molte. I personally would not consider using something like that it is better to have a conservation system that works exactly for your parameters because it makes the efficiency so much better.

    I think from this conservation system you have to use at least 1% to be sure it works in all mediums well enough and probably you need to use another conservation medium to help like Pentylenglycol or something similar with 3 -5 %. above ph 6.5 two parts of the system will be useless so I can use Benzylalcohol in a similar amount and have the same effect without building up the salt level in my Formulation.

  • abdullah

    May 12, 2023 at 5:02 am

    I have seen the patent. They use these amounts of glycerin and acids because they can be dissolved in these ratios. Not because they are more effective.

    For example if you increase the amount of an acid or don’t use that glycerin the Product would crystalize.

    So it is a good idea to use some extra acid with this preservative.

  • philgeis

    May 12, 2023 at 5:41 am

    This is just marketing BS - slightly acid to 8 is cynical marketing at best showing profound ignorance of the objective.

    Definitely weak vs Gram negative bacteria, again at any pH.

    Do not use this stuff - build a system that should work in context of your product.

    • graillotion

      May 12, 2023 at 6:54 pm

      @PhilGeis What would be your favorite “Gram - ” add-on….that would appeal to the ‘natural’ crowd? (I know…probably an oxymoron.)

      Seems like a number of combos sold…are a touch weak in this segment. Preferably….don’t answer….phenoxy….hehehhe.

      • This reply was modified 6 months, 3 weeks ago by  Graillotion.
  • philgeis

    May 13, 2023 at 6:45 am

    Aware of nothing for the natural “just stick this in” .

    Can construct effective systems that meet “natural” contrivance based on formula and with chelator, glycol (at decent %’s), organic acid, if benzyl alcohol - with benzoic acid, phenoxy (not phenyl), pH control, process and package design. Rarely see evidence of this in most of the clean beauty offerings.

    Sal acid has even been used as part but with very narrow, buffered pH range.

    • graillotion

      May 27, 2023 at 9:20 pm

      Dr Geis, @PhilGeis I came across this chart, which discusses the efficacy of benzyl alcohol based on pH. Naturally one knows the organic acids want a lower pH…but I had not seen this before. It does not show the rate of fall off…as pH increases. I believe I had read (maybe not true) that as pH rises, Benzyl alcohol is pretty much relegated to Y/M/F activity, and becomes progressively weaker on bacteria as pH rises?

      Now the chart does title the category ‘optimal efficacy’…so maybe there is not a lot of ‘fall off’ of efficacy with rise of pH, in relation to Benz alcohol?

      Could you elaborate…on the efficacy of Benz alcohol, in relation to this marketing blurb…and protection up to 8!!! We have already established the acids are worth ‘Jack Zero’ (stolen verbage)…. but what is happening to Benzyl…as we slide up the pH scale….to 8?

      Thank You. From the grasshopper.

      • philgeis

        May 28, 2023 at 10:10 am

        Gram + and fungi generally ~5 or less. Dave Steinberg liked it up to 7 - for me 7 and broader efficacy (some v. Gram neg) with benzoic acid in surfactants.

        What is ref 16?

        • This reply was modified 6 months, 1 week ago by  PhilGeis.
        • graillotion

          May 28, 2023 at 3:20 pm

          Dr Geis, @PhilGeis the reference 16 was this….and I do not have this book:

          1. E.Cahill, Benzyl Alcohol Monograph in: R.C. Rowe, P.J. Sheskey, P. J. Weller (Eds.), Handbook of Pharmaceutical Excipients, Fifth Edition, Pharmaceutical Press, 2006, pp. 69-71
          • This reply was modified 6 months, 1 week ago by  Graillotion.
  • Unknown Member

    Deleted User
    May 22, 2023 at 3:52 am

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