Xanthan Gum and Sodium Ascorbyl Phosphate (Vitamin C)

YulinYulin Member
edited July 2020 in Formulating
Hello everyone,

Does anyone know if there are compatibility issues with using Xanthan Gum and Hydroxyethylcellulose as a thickener in a Sodium Ascorbyl Phosphate Vitamin C Serum?   The serum is essentially SAP + Thickener + water + jojoba oil + preservative.  We have found that it turns from cloudy white to yellow about 2-3 weeks after blending which I'm guessing is oxidization.  Previously we were using carbopol 940 as the thickener in this  formula and we never had this color change issue unless we left it out exposed for several days.  Is the Xanthan somehow introducing more oxygen to the formula?   

Thanks for your help! 


  • @Yulin what you’re observing is the emulsion separating.

    SAP is naturally yellow like MAP (magnesium version). Both are stable versions of vitamin C, so I would not be as concerned about oxidation.

    The cloudy white you see is the dispersed jojoba oil as small droplets in the water. Carbopol 940 is be able to stabilize/emulsify a small amount of oils for longer than Xanthan without an emulsifier. Once the oil separates, you get the yellow water phase, and a top oil phase (which may be the same color causing you to not notice it).

    If you’re switching to Xanthan you’ll want an emulsifier or solubilizer (Polysorbate 80 could do), or remove the jojoba oil. 
  • YulinYulin Member
    @letsalcido thank you for this!  We were wondering how our competitors were just using xanthan for thickening.  I guess it must because their total oil content is probably lower.   We have already blended some of this formula - do you think we can add polysorbate 20 (we don't have any 80) now to provide long term stability?
  • I don’t know if that would work. I know polysorbate 20 is a solubilizer for fragrances and essential oils (light oils) mostly. You could test it with a sample.

    Maybe someone else will know if this works.

    @Yulin Do you not have any other emulsifiers you can use?
  • YulinYulin Member
    @letsalcido our manufacturer has a lot of things in stock but not polysorbate 80.  We have carbopol but that probably can't be added post production, right?  Any other ideas?  
  • @Yulin can you share your full formula? That way other people can also jump in. Depending on how large your oil phase is some emulsifiers will be better than others.
  • YulinYulin Member
    @letsalcido sure here is the formula:

    Water 90.340%
    Hydroxyethylcellulose 0.380%
    Xanthan Gum 0.430%
    Hyalurosmooth  0.100%
    MSM 1.000%
    Aloe 200 X  0.300%
    Jojoba Oil 0.700%
    Vitamin E 0.950%
    Sodium Ascorbyl Phosphate 5.000%
    Euxyl PE 9010 0.800%
  • letsalcidoletsalcido Member
    edited July 2020
    That’s a very small amount of oil, that’s probably why the carbomer alone was keeping it “emulsified”.

    A quick search shows jojoba has a required HLB of 10-11 https://www.researchgate.net/publication/262960061_Development_of_Jojoba_Oil_Simmondsia_chinensis_Link_CK_Schneid_Based_Nanoemulsions

    Ask your manufacturer to see what emulsifiers they have that can be added now (probably liquid ones) and have an HLB of around 10. You’ll likely need make some sample micro batches.

    Alternatively, I bought a serum once that had a similar composition as yours (plus essential oils) and it was also separated. For the regular eye it didn’t look like that, but I intentionally poured it in a clear bowl to analyze it and it was in fact separated. My point is, the average person won’t notice the separation with such tiny amounts of oil unless you have recurring customers that are used to seeing the opaque version.

    Just double checking, it turns from cloudy white to translucent yellow right?
  • YulinYulin Member
    @letsalcido thanks for the link.  I'll see if they have an HLB 10 liquid emulsifier at the manufacturing facility.  We have seen competing brands with similar xanthan formulas and no emulsifier which is what gave us confidence to try this.  I guess they are probably just selling separated formulas or have very low oil content.  

    Yes you're exactly right - it turns from cloudy white to translucent yellow.  
  • Sounds like you are trying to fix an existing batch...

    But going forward....what about clear Jojoba?

  • @Graillotion that's a great idea that I should have thought of!  Will give it a try. 
  • letsalcidoletsalcido Member
    edited August 2020
    @Yulin the yellow comes from the SAP not the Jojoba Oil.

    And the milky white comes from the dispersed oil droplets with diferente refraction index than water. If you want a clear serum you’ll need a high amount of solubilizer (or some types of lecithins that yield clear micro/nano emulsions) and high shear to create a nano emulsion.

    With your current formulation using clear jojoba won’t change anything.
  • @letsalcido the SAP we use is actually a fine white powder.  Is it supposed to be yellow?
  • @Yulin I’ve used MAP (magnesium ascorbyl phosphate) and it’s an off-white powder. Once in solution it turns yellowish.

    I have tried other products I bought for testing that were made with SAP and they had similar odor and color characteristics as MAP (looks yellow in solution and smells bready/yeasty), so I’m pretty sure if you make a 5% solution of that powder and nothing else you’ll see it’s yellowish.
  • Also, if we could magically dissolve 0.7% of unrefined jojoba oil in water by means other than micelle formation (which turns emulsions white), that amount of oil would not be nearly enough to make the full solution yellow. The oil is not that strongly colored.  
  • @letsalcido that makes sense.  We are going to try adding Emulgin SG to the formula to see if it disperses the jojoba to turn the serum back to creamy white.  
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