Home Cosmetic Science Talk Formulating What can I add to this formula to make it feel nicer

  • What can I add to this formula to make it feel nicer

    Posted by esthetician922 on May 21, 2020 at 2:46 pm

    distilled water

    81.89%

    lactic acid

    11.11%

    sodium pca +

    glycerin

    5.00%

    green tea extract

    1.00%

    <xanthan gum>

    1.00%

    right now it feels “OK” it absorbs but it makes my skin feel tight and shiny. I know I have a high acid in there but I need it. I was thinking of butylene glycol or propendial 1,3 or both. Also, the ph is a tad low for me it’s @ 2.5 on a ph strip (my ph meter is on the fritz). What can I add to increase the ph to a 3?

    Anca_Formulator replied 2 weeks, 1 day ago 10 Members · 26 Replies
  • 26 Replies
  • Pharma

    Member
    May 21, 2020 at 3:21 pm

    A glycol sounds good and in order to increase pH, add a base (NaOH or KOH will do). Alternatively, don’t add pure lactic acid but a blend of lactic acid and a lactate salt (sodium lactate). This however requires that you calculate it (knowing about buffers will help) though it won’t be super accurate even with the right formula.

  • esthetician922

    Member
    May 21, 2020 at 10:03 pm

    @Pharma
    just curious why do you say to add sodium lactate to lactic acid? 

  • Pharma

    Member
    May 22, 2020 at 6:25 am

    A mixture of the right proportions of lactic acid with sodium lactate gives a higher pH than pure lactic acid.

  • DeedeeUkulele

    Member
    May 22, 2020 at 6:39 am

    Are you using 90% lactic acid? (I’m assuming you’re trying to make 10% lactic acid). Adding sodium lactate to lactic acid would yield a higher pH than the acid alone, although you might need to add some NaOH to bring the pH up to 3 (I believe the ideal pH would be 3.5-3.8). I’ve made some high strength lactic acid peels with sodium lactate, and even with a 1:1 ratio, I could only get the pH up a few decimal points, but keep in mind that’s with 50-65% lactic acid. 

  • Pharma

    Member
    May 22, 2020 at 11:34 am
    As an example: to achieve a pH of 3.86 (equals pka of lactic acid), you’d need 1 mol-equivalent pure lactic acid and 1 mol-equivalent of pure sodium lactate. Converting molecular weight into gram gives you 1.112 g sodium lactate for every gram of lactic acid 90%.
    To calculate a different pH, use the Henderson-Hasselbalch equation and don’t forget to calculate in mol, not grams, and consider dilutions if working for example with 90% lactic acid. Also, don’t just add sodium lactate to your 10% lactic acid but calculate the required ratio which would equal 10% lactic acid plus sodium hydroxide. In above case, you’d have to use 5.265 g lactic acid 90% and 4.735 sodium lactate to obtain a buffered ‘10% lactic acid’ at pH 3.86.
    • BetaOneChem

      Member
      May 27, 2024 at 8:57 am

      Can you please break this down? how do you implement Dilution Into this if we are using The H:H method?

  • ngarayeva001

    Member
    May 22, 2020 at 12:35 pm

    @Pharma, when you calculated sodium lactate did you assume it’s 100% sodium lactate? I decided to check how my lactic buffer template works (because I am not a chemist and I put it together based on my understanding) and run your numbers and it gives me 3.55. So my formula is either wrong or you assumed pure sodium lactate.

  • Pharma

    Member
    May 22, 2020 at 2:24 pm
    100% sodium lactate and 90% lactic acid for a pH which equals pka.
    And shush, I mixed stuff up and posted an error: 5.528 pure sodium lactate and 4.472 lactic acid 100% or 4.960 lactic acid 90%.
    Good observation!
  • esthetician922

    Member
    May 22, 2020 at 2:50 pm

    oh wow, ok, thank you. Yes, I am using 90% lactic acid. So then if I am only using 4.960 of lactic acid then would that change my formula to a 5% lactic acid serum? (I rounded up)

  • ngarayeva001

    Member
    May 22, 2020 at 3:54 pm

    @Pharma, thank you so much! It means my template works!

  • Pharma

    Member
    May 22, 2020 at 5:40 pm

    oh wow, ok, thank you. Yes, I am using 90% lactic acid. So then if I am only using 4.960 of lactic acid then would that change my formula to a 5% lactic acid serum? (I rounded up)

    Only if you didn’t add sodium lactate and it have a higher pH than you already have. It only works if you add sodium lactate!
    Given that cosmetics is great at marketing but sucks at telling the truth, the whole truth, and only the truth, a mix of 5% lactic acid with 5% sodium lactate would probably be considered a buffered 5% lactic acid serum whereas a 10% lactic acid with 5% relative amount of sodium hydroxide would most likely be considered a buffered 10% lactic acid serum. Both will be 100% identical and, chemically speaking, be 5% lactic acid. What’s sold out there is usually buffered to some extent and nobody cares that this turns the acid into a salt. Hence, call it whatever you like as long as it contains 10% lacti-something. ;)
  • esthetician922

    Member
    May 25, 2020 at 9:56 pm

    @ngarayeva001
    do you mind sharing your template for me to use? I can give you my email. Thank you for considering! Also, can you work backwards? For example, if I know what I want the ph to be can I add that percentage first and then add in the lactic and lactate?

  • alan123

    Member
    May 25, 2020 at 10:17 pm

    Is this meant to be a serum? 

    you can try replacing Xanthan Gum with Siligel.

    Also, I like mixing Siligel with Sepinov emt 10. However, not sure how Sepinov will deal with lactic acid. You can try mixing 0.3% Siligel 0.4% Sepimax Zen and 0.2% Hyaluronic acid High molecular weight.

    Also, you can replace sepimax Zen 0.3% with Sepinov emt 10 - 0.3%. The texture would be a bit nicer and add later lactic acid see how is behaving if it is loosing consistency go back to Sepimax Zen.

    Not thick enough..? increase %s

  • esthetician922

    Member
    May 26, 2020 at 3:47 am

    @alan123
     yes it’s a serum. thanks for the advice! I’ll try it. 

    • busola

      Member
      June 27, 2024 at 2:42 pm

      I need your assistance on how to use siligel and zen together in a moisturizer. Thank you in advance

  • joowan11

    Member
    May 29, 2020 at 6:29 pm

    @esthetician922 I will attach the file to the post. I have basically the same template as @ngarayeva001 ^^. Also, regarding the consistency, I also suggest Siligel. Also you could try a bit of HMW HA (it would look nicer, crystal clear. The siligel can sometimes make it kinda murky tbh)

  • ngarayeva001

    Member
    May 29, 2020 at 8:13 pm

    @czkld may I ask where did you find yours?

  • joowan11

    Member
    May 29, 2020 at 8:20 pm

    @ngarayeva001
    a friend of mine who is a chemist sent it to me 

  • ngarayeva001

    Member
    May 29, 2020 at 9:02 pm

    I think it’s my duty to warn everyone about using such templates. The math might be right but pH is extremely complex thing. This calc works on paper, but other ingredients might have significant  influence on the overall system. Acids must be treated with respect. I use this template to make acid peels for my personal use but I would never share it with anyone else. I am sure people with more experience would support me on this.

  • ngarayeva001

    Member
    May 29, 2020 at 9:25 pm

    Sorry just to emphasize it even more, I have the least sensitive skin among everyone I know. Most people won’t be able to tolerate what I can when it comes to pH. Be very careful with acids.

  • joowan11

    Member
    May 29, 2020 at 9:30 pm

    @ngarayeva001 yes, I 100% agree. this is a v rough estimate and you really need a proper ph meter or at least strips to determine the actual ph in the product. I use it to calculate the buffer sometimes. 

  • Pharma

    Member
    May 29, 2020 at 9:32 pm
    I can only concur with both of you!
    Always measure pH.
  • esthetician922

    Member
    May 29, 2020 at 9:57 pm

    yes, of course, I wouldn’t use unless I measured the ph but to get a sense of how to make it higher is all I would use it for. Thanks!

  • Anca_Formulator

    Member
    June 27, 2024 at 3:44 pm

    Adding 0.2% Sodium Phytate buffer should bump up the pH some.

    Are you using a preservative?

    • fareloz

      Member
      June 28, 2024 at 5:00 am

      Sodium Phytate is usually used as a chelating agent, not pH adjuster. Sodium Hydroxide (NaOH) is more preferable choice.

      • Anca_Formulator

        Member
        July 2, 2024 at 12:27 pm

        Yes, indeed. I noticed her formula didn’t have a buffer. I use sodium phytate primarily as a buffer in my formulations. While its main function is to stabilize the pH, I’ve noticed that it also tends to increase the pH a bit, so two birds with one stone. To fine-tune the pH levels, I typically use lactic acid and sodium hydroxide (NaOH) for adjustments. I should have phrased this better 😉

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