Home Cosmetic Science Talk Formulating Potassium vs Sodium Hydroxide vs Other neutralizers in AHA formulas?

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  • Potassium vs Sodium Hydroxide vs Other neutralizers in AHA formulas?

    Posted by Zink on April 28, 2017 at 6:12 pm

    I’m looking to get a 5% Glycolic Acid lotion up to pH 4, and I have a customer asking for a very minimal formula without what he perceives as nasty chemicals. 

    Sodium Hydroxide is OK, but is it interchangeable with Potassium Hydroxide for this kind of formula? TEA is out. Open to other gentle options :)

    belassi replied 7 years, 1 month ago 6 Members · 8 Replies
  • 8 Replies
  • beautynerd

    Member
    April 28, 2017 at 6:22 pm
  • MarkBroussard

    Member
    April 28, 2017 at 6:31 pm

    Sodium Lactate

  • Zink

    Member
    April 28, 2017 at 8:31 pm

    Trouble with sodium lactate is that you need 10% to get to pH 4 in a 5% Glycolic Acid solution.

  • Microformulation

    Member
    April 28, 2017 at 9:20 pm

    In my experience use the Sodium Hydroxide and keep it simple. You may also want to look at some of Dupont’s documents and read up on how they pre-neutralize their Glycolic acids.

    https://www.chemours.com/Glypure/en_US/products/neutralized_glypure.html

  • belassi

    Member
    April 28, 2017 at 10:55 pm

    Someone please explain how a SALT is going to act as a base. ACID+BASE->SALT+WATER. From this I do not see how a salt is going to neutralise an acid. Not to mention that for instance, sodium gluconate has pH=7. Sodium lactate has a pH of only 8, why would you use a lot of that, instead of adding lactic acid?

  • MarkBroussard

    Member
    April 29, 2017 at 2:04 am

    Sodium Lactate is a natural moisturizer, so not only does it raise the pH, you get the added benefit of increased moisturization.  It’s going to be your most gentle, most natural option.

    Ask you client which they prefer:  NaOH, KOH or Sodium Lactate … they’re all going to work.  Perhaps even add 1% Panthenol.  Or, as also suggested Sodium Gluconate, AMTIcide, Panthenol and Sodium Lactate.

    @Belassi:  Lactic Acid is not going to help raise the pH, I don’t think.

  • DRBOB@VERDIENT.BIZ

    Member
    April 29, 2017 at 3:19 am

    Actually any salt of a weak acid and strong base will raise PH but why complicate things when you can use NaOH?

  • belassi

    Member
    April 29, 2017 at 5:30 am

    Sorry I was thinking back to front regarding lactic acid. I agree with DRBob

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