Lactic Acid and Glycolic Acid Face Cream - A Formula Critique

Hi, I have created a formula for a lactic and glycolic acid face cream for personal use. The goal is to use this several times per week or even nightly to reduce hyperpigmentation on dark skin type and simply brighten and even tone. 

My questions are:
The best chelating agent (I list the two I have in mind) 
Preservative system is good for this?
Concentrations of LA and GA will be effective?
Do I really need tocopherol to help the sunflower and grapeseed oil last?
Would it help to add Potassium Azeloyl Diglycinate to the formula? I would love to use this ingredient as well.

Note, this is not meant to be the main moisturizer. It is meant to go under the main moisturizer and just act as the exfoliation treatment.

water55.00%
glycerin4.00%
xantham gum0.30%
sodium gluconate OR disodium EDTA0.20%
Lactic acid 88 (5% active) 6.00%
Glycolic acid 70 (3% active)4.50%
Emulsifer (Cetearyl alcohol, glyceryl stearate, sodium stearoyl lactylate)4.00%
sunflower oil2.00%
grapeseed oil1.00%
stearic acid2.00%
licorice extract1.00%
d panthanol0.50%
dl-alpha tocopherol
0.50%
dimethicone1.00%
ph adjuster to 3.5 - 3.8
Caprylyl glycol0.08%
Phenoxyethanol & Ethylhexylglycerin1.00%

Thank you for your critique. 

Comments

  • PharmaPharma Member, Pharmacist
    At very low pH, EDTA and gluconate won't perform well (if at all). Phytic acid on the other hand still works at such a pH.
    Probably up caprylyl glycol or are you using a blend such as Lexgard HPO? That cocktail and the very low pH should work very well.
    AL & GA: Effective for what?
    No, you don't REALLY need tocopherol, any lipohilic antioxidant will do :blush: .
    Azeloyl diglycinate: I was all ahhh and ohhh when I stumbled upon that ingredient. Further reading turned it into a pfff and meh. Sure, use it and let us know what you think about it! Would be nice knowing.
  • Hi @Pharma, thank you for the feedback. Was not even aware to use Phytic as a chelating agent. This is great information for me to look into.

    On the caprylyl glycol, I can up that.  Is 1.5% sufficient? It is not Lexguard HPO but a blend of caprylyl glycol (67-73%) and ethylhexylglycerin (27-33%).  I used it in addition to my main preservative blend (Phenoxyethanol & Ethylhexylglycerin) on basically all of my emulsions.

    AL & GA: I consider  any decrease in the appearance of post-acne marks/ hyper-pigmentation and improved smoothness in skin texture to be my standard for effectiveness.  

    Azeloyl diglycinate: I've been trying to read studies on this. I'll add it and see if the overall formula shows marked improvement and will give feedback on my take. 

    Thanks for your help. BTW, I am somewhat new at this in that I started research a few years ago how to make products.  This is my first posted question. Your insight on the various questions along with others' insights is a real education. 

  • Ok, so I checked on ways to purchase Phytic Acid. I found Sodium Phytate @ lotion crafters.  I'll be ordering it  for this formula. Thanks for the suggestion.
  • EDIT
    On the caprylyl glycol, I can up that.  Is 1.5% sufficient? Typo:( Not sure what I was thinking. More like is 0.5% sufficient. 
  • @Pharma, would gluconolactone work? In that case it can be added at higher amount as a PHA and have double function (as a chelator and as a polyhydroxy acid 
  • PharmaPharma Member, Pharmacist
     @ngarayeva001 Gluconolactone is slow release gluconic acid (not so slow in alkaline and very acidic solution). It also helps preventing a formula becoming too alkaline (something that's obviously not going to happen in above serum) similar to triethyl citrate but pH and not microbial metabolism driven. Since it doesn't change pH, you can add it to a cream at for example pH 6 and the cream will still be pH 6. Should pH rise (bacterial growth or the like) makes it degrade turning into gluconic acid and thereby lowering pH back to 6 (that's at least the theory). Directly adding gluconic acid turns the cream to probably pH 5 and you have to add a base = more work.
    @skininthegame 0.5% caprylyl glycol sounds reasonable = manufacturers recommendation.
    Yup, sodium phytate is what's commonly sold as "phytic acid".
  • @ngarayeva001, thanks for the into to PHAs. This is interesting to me. May have to make an exfoliation serum for more AHA sensitive skin with this.

    @Pharma , many thanks for recommendations. I've updated my formula and will let you know how it all turns out.

    Cheers!
  • MarkBroussardMarkBroussard Member, Professional Chemist

    Yup, sodium phytate is what's commonly sold as "phytic acid".
    If I may clarify that ...

    Phytic Acid and Sodium Phytate are two different ingredients.  Sodium Phytate is a white powder that has a native pH of 12 ... use it to raise the pH of a formulation. 

    Phytic Acid has a native pH of 3 and you use it to lower the pH of a formula.
    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 www.desertinbloomcosmeticslab.com
  • @MarkBroussard, noted.  In that case, is sodium phytate a good sustitute for TEA and able to do double duty (ph adjuster + chelating) in my formula in that regard?


  • MarkBroussardMarkBroussard Member, Professional Chemist
    Yes, Sodium Phytate can function both as a chelating agent and can be used to adjust your pH up.

    If you want to adjust your pH to more acidic levels, then you'll want to use Phytic Acid.
    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 www.desertinbloomcosmeticslab.com
  • @MarkBroussard, perfect. Thank you for confirming! 
  • PharmaPharma Member, Pharmacist
    @MarkBroussard Thanks for the complement. So phytic acid really is available. Never seen it being sold.
  • EVchemEVchem Member
    edited September 23
    @Pharma company called Biosil  Technologies sells it in relatively small MOQ (~5kg) 
  • PharmaPharma Member, Pharmacist
    For me, that MOQ is huge :o ! But thanks anyway (who knows when/if that might come in handy)!
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