Home Cosmetic Science Talk Formulating Syneresis (leaking) of deodorant stick

  • Syneresis (leaking) of deodorant stick

    Posted by Margaret on February 23, 2023 at 3:22 pm

    This is driving me MAD.

    I’ve tried different things with the ingredients I have, and the stick STILL develops droplets on the surface about 24 hours after using it.

    I see pooling of liquid on the bottom AND on top of the deodorant material (which I store in a plastic bin, till I want to make a stick of it, with fragrance).

    Pooling/droplet formation occur with or without any fragrance added to the deodorant material.

    MY CURRENT FORMULA:

    6% sodium stearate (OP-200 V from Hallstar, the preferred variety for glycol sticks)

    57% propylene glycol

    10% dipropylene glycol

    4 % Peg-40 castor oil

    6% witch hazel (no alcohol in it)

    14% water

    3% isopropyl myristate

    HERE ARE THE THINGS I’VE VARIED, WITHOUT A RESULTANT HAPPY FACE FOR SUCCESS:

    Polysorbate 80 at 1.5% when scenting the deo. with essential oils, also at 1.5%

    1% sodium choride (non-iodized pickling variety). The syneresis looked WORSE.

    Sodium stearate OP-100V or OP-200V made NO difference. The OP-200V is supposedly better for glycol sticks, such as what I’m making.

    67% propylene glycol (PG) or a 57% PG and 10% dipropylene glycol (DPG)

    PEG-40 castor bean oil 2% to 4%

    Isopropyl myristate, 3% OR 6%

    6% sodium stearate OR 8% sodium stearate

    I am limited by the ingredients I can get because I’m just a hobbyist. I DO have these ingredients, if they’d be helpful?

    cetyl alcohol

    brassica alcohol

    sodium stearate

    Margaret replied 7 months, 2 weeks ago 3 Members · 4 Replies
  • 4 Replies
  • Bill_Toge

    Member
    February 23, 2023 at 4:16 pm

    I’d suggest getting rid of the PEGylated oil altogether; it’s not necessary, and is likely contributing to the formula’s tendency to draw water from the air

    I’d also suggest getting rid of the IPM, as it’s not miscible with the rest of the stick, and stick formulas are best kept monophasic

    • This reply was modified 1 year, 3 months ago by  Bill_Toge.
  • Margaret

    Member
    February 23, 2023 at 5:05 pm

    Ooooowa. I’ll try your suggestions!

    Thanks man!

    • Ying

      Member
      June 19, 2023 at 11:28 am

      Margaret: Did your problem solved?

      • Margaret

        Member
        October 29, 2023 at 11:22 am

        It is MUCH better without the IPM. Who knew? (Not me, thus my question here)

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