Preservatives and Xantham Gum

Can anybody tell me if it's better to dissolve preservatives in water before adding the xantham gum (as I suppose) or to add them after? I would like to know the most effective procedure. Thank you to everybody!


  • Are you talking about solid preservatives, or liquid? 
  • Liquid. I'm using Germall Plus Liquid.
  • Is Germall added in th beginning or the end phases? If it can be added in the end phases then you don’t have to worry about xanthan gum 
    Dr. Catherine Pratt
    (B.Sc with HONS I , Ph.D Analytical/Organic Chem and Microbiology), Cosmetic Chemistry IPCS)
  • I can add it at the end. In the mixture clay is also added to Xantham gel. Should I add Germall as last step? Thank you very much for your help.
  • Yes πŸ˜€πŸ˜ƒ
    Dr. Catherine Pratt
    (B.Sc with HONS I , Ph.D Analytical/Organic Chem and Microbiology), Cosmetic Chemistry IPCS)
  • MarkBroussardMarkBroussard Member, Professional Chemist

    Given that you are adding clay to your concoction, I would recommend that you add in this order to your water phase:  (1)  Preservative; (2) Clay; (3) Xanthan Gum

    You want to Preservative to penetrate into the interstitial spaces of the clay matrix.  If you add the Xanthan Gum before the Preservative, you will reduce the ability of the Preservative to penetrate into those interstitial spaces and you may have issues with mold growth, in particular.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details
  • Hi Mark,thank you for your answer, this is the "Ashland" approch and has its pros, but Germall at first step makes the final product full of very stable little bubbles .

  • @MarkBroussard has a good point. You should make sure the preservative is very well homogenized.
  • Thank to you all. I decided to test the "Germall Last"solution at a high concentration and "Germall First" at a lower one, but with longer time for homogenisation. I'll keep you updated with the results.

  • Hi Guys!
    At the moment the best sample "Germall First" is with 0,2%, the best sample "Germall Last" is with 0,5%. "Germall Last" solution can't work with <0,5% in my case, but it is still the best way to avoid bubbles. Thank you so much!

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