Home Cosmetic Science Talk Formulating SCI powder in lower pH formulation (4.5)

  • SCI powder in lower pH formulation (4.5)

    Posted by Zoya on August 14, 2023 at 7:04 am


    I would like to know if anyone have experience in using SCI powder in a lower pH formulation (pH 4.5) (liquid surfactant system). I usually use it in formulations which have a pH around 5.5-6, but in this case I would like to add some actives which work best at lower pH (I know, it’s a wash-off product so it doesn’t have that much ‘effectiveness’ even in the right pH). My question is: how does pH 4.5 affects SCI’s stability?


    Zoya replied 8 months, 1 week ago 3 Members · 4 Replies
  • 4 Replies
  • Paprik

    August 15, 2023 at 8:38 pm

    According to the suppliers the pH should be within 6-8. It might hydrolyze out of that range.

    If we take into consideration that pH drifts over the product’s shelf life, I would definitely aim for pH 7.

    Use the active at 0.001% and you can make good marketing story and not worry much about stability.

  • Zoya

    August 15, 2023 at 10:51 pm

    Hi Paprik.

    Thank you so much for your reply. I was thinking to use it as the anionic surfactant for a slightly acidic cleanser, as I have successfully made stable and functioning liquid gel cleansers with it - but in those cases the pH was 6. I have never tried to bring pH down as I was worried of hydrolisation and I planned to use a glutamate for the lower pH cleanser because they tend to ‘work’ between pH 4-6. Unfortunately I don’t have much luck with glutamates lately so I considered changing the anionic surfactant to SCI. Seems a bad idea now. Still don’t know what to do, I have very few options to use as surfactants.

  • ketchito

    August 16, 2023 at 2:39 pm

    Why don’t you use sulfonates (like alpha olefin sulfonate)? They are very stable at low pH. Same as for SLS.

    • Zoya

      August 17, 2023 at 1:21 am

      Hi ketchito,

      Thanks for the idea, I order some and play with it. I’m also experimenting with glutamates right now, they can tolerate lower pHs as well.

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