Home Cosmetic Science Talk Formulating Discoloration during stability green clay and matcha powder facial mask

  • Discoloration during stability green clay and matcha powder facial mask

    Posted by Andreea on November 15, 2024 at 9:04 am

    Hi,

    I’m developing a facial mask formula containing green clay and matcha powder. The product turns brown after about 20 days, both at 40°C and RT stability.

    It contains 3% cupuacu butter, 6% olivem 1000, and 1% stearic acid as the oil phase. Water + hydrosol + tetrasodium glutamate diacetate 0.15% as water phase. Preserved with geogard ECT. It contains 0.3% actual tocopherol and some extracts (green tea + concentrated mix of different extracts). pH 5.3-5.8.

    For the green clay and matcha, I have tried:

    1. Initial formula: 4% matcha powder and 2% green clay
    2. Current formula: Reduced matcha to 0.5% and kept green clay at 2%

    The brown color change still occurs with the reduced matcha 0.5% input.

    I am thinking of reducing the matcha to 0.1% while keeping the green clay at 2%. Or even take matcha out.

    Has anyone worked with matcha powder in formulations and experienced similar issues?

    Any recommendation would be highly appreciated.

    Aniela replied 1 month, 1 week ago 2 Members · 1 Reply
  • 1 Reply
  • Aniela

    Member
    November 15, 2024 at 9:56 am

    Hi,

    1. Clay masks are notoriously difficult to preserve, and I highly doubt that geogard+TGDA will do the job. On top of that, you have hydrosol in there plus some other plant extracts, and all of these contain yummy bug-food. If cupuacu it’s unrefined, it also contains some bug-food.

    2. Regarding the change of colour, it occurs usually with any plant-powder, it’s not a matcha-related issue. Most of the powder-solutions (water) will have a beautiful colour at a very acidic and/or alkaline pH, but will become “ugly” at a skin-friendly pH- for example, hibiscus turns gray. Also light and heat can further affect the colour.

    3. Cupuacu is a fairly stable butter, so no need to add tocopherol, and increase your cost.

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