Home Cosmetic Science Talk Formulating HA serum seems stable but separates after 2-3 weeks

  • HA serum seems stable but separates after 2-3 weeks

    Posted by JThompson on March 15, 2024 at 8:03 pm

    Hello group! Delighted to be here.

    I’ve been working on emulsion based facial serum for nearly a year and continue to encounter the same issue regardless of formula swaps so at this point I am assuming it is a technique-sensitive issue: emulsion appears stable and lovely.. for about a few weeks. It then slowly begins to separate from the bottom.

    I am using LMW HA at 1.5% + HMW HA at 1% and hydrating in my water phase, then heating prior to homogenizing with my heated oil phase. I have read a couple very brief passages from others suggesting that HMW HA should never be added pre-emulsion.

    Could this be my issue? Why would an emulsion appear stable only to separate weeks later?

    King thanks in advance for your value time and expertise. Looking forward to discussing.

    ketchito replied 1 month ago 3 Members · 2 Replies
  • 2 Replies
  • Juggsy

    March 20, 2024 at 2:50 am

    I think you are breaking the gel with the shear.

    I believe that excessive shear can potentially degrade HA molecules, leading to reduced effectiveness or even instability in the formulation.

    Try adding HMW HA to the cool-down phase after emulsification is complete and the mixture has cooled down to around 40–45 °C. This might help improve stability as it reduces the exposure of HMW HA to high temperatures and shear forces during the emulsification process. Or only use low shear once you’ve added the HA like you’d do with carbomer.

  • ketchito

    March 20, 2024 at 5:58 am

    Without knowing what else is in your formula, it’s pretty hard to guess.

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