Home Cosmetic Science Talk Formulating General Preservative charge for conditioner

  • Preservative charge for conditioner

    Posted by cossci21 on October 18, 2025 at 5:25 pm

    Hi i am working on a conditioner using behentrimonium methosulfate, the client uses a approved preservative which is: aqua, sodium levulinate, potassium sorbate.

    When i add it in it clearly thins down the conditioner assume due to sodium levulinate being anionic but seems to hold together ok.

    Do i need to worry about long term stability? Or should it be ok?

    Thankyou

    PhilGeis replied 1 week, 6 days ago 5 Members · 7 Replies
  • 7 Replies
  • PhilGeis

    Member
    October 19, 2025 at 10:38 pm

    You need to worry about the consumer / that is a garbage preservative system.

  • Sarataylor

    Member
    October 24, 2025 at 6:53 am

    That’s a normal reaction with BTMS and that preservative combo. As long as the emulsion isn’t breaking, it’s likely fine, but I’d suggest a short stability test just to double-check long-term performance.

  • Stevie Kae

    Member
    October 31, 2025 at 5:55 am

    You’re right — <strong data-start=”31″ data-end=”70″>sodium levulinate is mildly anionic, so it can partially neutralize the <strong data-start=”107″ data-end=”124″>cationic BTMS and thin the emulsion. If it stays stable (no separation, pH around 4.5–5.5), it’s usually fine short term, but <strong data-start=”237″ data-end=”278″>long-term stability could be affected. Do a few <strong data-start=”289″ data-end=”320″>accelerated stability tests (heat, freeze–thaw, time) to be sure before finalizing the formula.

  • PhilGeis

    Member
    November 1, 2025 at 8:46 am

    Please - this is a garbage preservative system as is - even without the formula incompatibility and likely pH problem (most conditioners pH < 5). Depending on your water system quality , you may have trouble making it clean, but be assured consumers will contaminate.

    I’ll add - whatever preservative system you use, you’re responsible for the life of the product and that means more than a “few” or “short-term” stability tests.

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