Home Cosmetic Science Talk Formulating Preservative issue

  • Preservative issue

    Posted by Sumayia on November 13, 2019 at 5:47 pm
    Hi every one .. really your advice here will be much appreciated..
    I make  my own cleansers and toners .. I add a bunch of glycerites to both of them which are extracred through  water and glycerin  and already  preserved  from the supplier.. Since  Iam  buisy these  days and gathering and weighing the extracts each time I  make my toner and cleansers is time consuming I decided to make two mixtures , one containing the glycerites I add to the toner in a base of propanediol .. and another containing the glycerites I add to the cleansers in a base of propanediol and surfactants.. .. so each time I make my stuff I have my exteacts ready .. just incorporate water and preservative and adjust the ph.
    My question is .. do I have to add a preservative to the pre prepared mixtures which only contain the propanediol , glycerites and surfactans  or is it ok to  keep them  the way they are since there is no water in them ??
    Sumayia replied 5 years, 8 months ago 2 Members · 4 Replies
  • 4 Replies
  • OldPerry

    Professional Chemist / Formulator
    November 13, 2019 at 11:32 pm

    To be safe, I would add additional preservative. Your surfactants probably have water in them unless they are powders.

  • Sumayia

    Member
    November 14, 2019 at 4:16 pm

    Hi and thank you so much for responding, but further explaination would be much appreciated here .m  the surfactant part is clear here but what about the glycerites.. they contain water and glycerin and preserved from the supplier in their  sollow form . I just mix already preserved glycerites in propanediol, is that unsafe too.. thanks in advance and sorry if I am asking too much

  • OldPerry

    Professional Chemist / Formulator
    November 14, 2019 at 4:24 pm

    The only way to really answer your question is to test the sample as to whether you get microbial growth (challenge test). Any advice I give is just a reasonable guess but individual circumstances will vary. 

    If your glycerites have a low level of water activity then you probably don’t need additional preservative. That’s why something like Honey which is high in sugar doesn’t typically need preservation. There is not enough available water for microbes to grow. Since your not adding additional water but just adding to the propanediol, you probably don’t need additional preservation. But only testing can tell you for sure.

  • Sumayia

    Member
    November 14, 2019 at 10:45 pm

    Thank you so much :)

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