Home Cosmetic Science Talk Formulating sticky serum needs help

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  • sticky serum needs help

    Posted by doingdewy on July 27, 2022 at 2:20 pm

    Hi 

    I’ve created a Niacinamide serum that I’ve intended to be lightly hydrating, with good spreadability and a smooth, non-sticky finish.

    The resulting texture feels grippy on dry down, and quite unpleasantly sticky.

    I’m struggling a bit to figure out which ingredient (or combination) is creating the tackiness as I’ve tested isolated solutions of each ingredient and they are definitely un-tacky by themselves.

    The serum:

    5% Niacinamide
    6% 1,3 Propanediol
    1% Sodium Lactate
    2% Polyquaternium 7
    2% PEG-12 Dimethicone
    0.2% Phenyl Trimethicone
    0.2% Hydroxyethylcellulose
    0.5% Phenoxyethanol/ethylhexylglycerin 

    The inclusion of trimethicone did help a little, but it made the serum slightly cloudy. I don’t want to include any more oil phase as I’m trying to keep it the serum as clear as possible, I’ve included the propanediol at that amount to help keep the preservative at 0.5% 

    Any suggestions would be greatly appreciated. 

    Side note: Cosmetic ingredients are extremely limited where I live, so I don’t have access to any other humectants or water-soluble silicones except for Sorbitol, Glycerin and Propylene Glycol. 

    OldPerry replied 1 year, 9 months ago 2 Members · 2 Replies
  • 2 Replies
  • OldPerry

    Member
    July 27, 2022 at 7:35 pm

    Can we assume that the unlisted ingredient in your formula is water?

    If this is the case, the reason is probably because you are at 15% solids with all the ingredients considered. Cut the total down to 10% or even 5% solids and see what happens. This would involve reducing the concentrations of Niacinamide, 1,3 Propanediol, Polyquat 7, and PEG-12 Dimethicone.

  • doingdewy

    Member
    July 30, 2022 at 10:45 am

    Perry said:

    Can we assume that the unlisted ingredient in your formula is water?

    If this is the case, the reason is probably because you are at 15% solids with all the ingredients considered. Cut the total down to 10% or even 5% solids and see what happens. This would involve reducing the concentrations of Niacinamide, 1,3 Propanediol, Polyquat 7, and PEG-12 Dimethicone.

    Thanks for your input Perry, and your assumption was correct.

    That makes a lot of sense, considering the isolated tests I did with each ingredient had higher free water content.

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