Home Cosmetic Science Talk Formulating Best preservative for pH > 7 liquid mud / clay face masks?

  • heraklit

    May 16, 2015 at 1:09 pm

    It’s advisable first, to sterilize the mud with gamma rays.

  • Bill_Toge

    May 16, 2015 at 2:02 pm

    if you’ve got large amounts of clay in your formula you’ll need something substantially water soluble (i.e. not phenoxyethanol) or else it’ll adsorb onto the clay and be rendered ineffective; the only time I’ve ever seen Euxyl PE9010 fail a challenge test was in a formula with 20% clay in it

    Suttocide A, sodium hydroxymethylglycinate, is supposed to be effective at high pH, though I’ve not used it myself

  • MarkBroussard

    May 16, 2015 at 2:15 pm

    Suttocide A … I would stay away from it … serious eye irritation from the fumes and it has a nasty smell.

  • MarkBroussard

    May 16, 2015 at 8:41 pm

    You might try acidifying your concoction to pH below 6, if that does not create conflicts with other ingredients, to give you a wider selection of Preservative options.

    Adding ethylhexylglycerin at 1% (its max solubility in water) generally will boost the efficacy of some Preservatives up to pH 9 or so.

  • beautynerd

    May 17, 2015 at 3:30 am

    Could you also replace the Leucidal with Polyaminopropyl Biguanide?

  • Zink

    May 18, 2015 at 5:30 pm

    Thanks @MarkBroussard

    Do you know anything about how Ethylhexylglycerin compares to Diazolidinyl Urea (and) Iodopropynyl Butylcarbamate or were you thinking of using the together?

    Any obvious disadvantages of reducing pH to 6? I’m using 5-10% calcium carbonate so It might not be practically viable to do so.


    Not really looking to replace it, rather add another preservative.

  • MarkBroussard

    May 18, 2015 at 10:11 pm

    Ethylhexylglycerin is a preservative booster … it’s mechanism of action is to weaken the micorbial cell wall making it easier for the actual preservative to penetrate the cell.  So, you might go with a blend of Benzyl Alcohol/Ethylhexylglycerin or Phenoxyethano/Ethylhexylglycerin.

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