Home Cosmetic Science Talk Formulating Skin Rancid odor in final product, but raw ingredients still smell fine

  • Rancid odor in final product, but raw ingredients still smell fine

    Posted by simplepimple on July 4, 2025 at 10:00 pm

    Hello,

    I am formulating a face moisturizer (see formula below) for my small business. Currently undergoing stability testing, and it has been 1 month since making the product. Everything is good so far, except the odor. The final product has gone from a faint peppery scent (from the black seed oil) to a rancid odor. Most raw ingredients used, particularly the oils and butter, were new when making the product.

    I’ve been trying to figure out what has caused the rancidity. I checked the raw ingredients, and they have not gone rancid and still smell as they did when I first opened them. The pH of the final product still remains the same between 4.5 and 5.0. Any ideas of what could be causing the odor? Is there anything I need to add or change in my formula to avoid the rancid odor?

    Heated Water Phase:

    Water q.s. 100%

    Sodium phytate 0.2%

    Propanediol 4%

    Glycerin 4%

    Sepimax zen 0.3%

    Heated Oil Phase:

    Olivem 1000 2.5%

    Glyceryl stearate 1%

    Cetyl alcohol 1.3%

    Refined shea butter 2%

    Isoamyl laurate 2%

    Pomegranate sterols 1%

    Cool Down Phase:

    Allantoin 0.3%

    Dimethicone 1%

    Black seed oil 1.5%

    Irish moss extract 0.2%

    Sodium benzoate 0.35%

    Lotioncrafter PE 9010 1%

    Mixed tocopherols T50 0.1%

    Lactic acid (pH adjuster)

    PhilGeis replied 1 hour, 13 minutes ago 2 Members · 2 Replies
  • 2 Replies
  • simplepimple

    Member
    July 5, 2025 at 12:13 am

    Forgot to mention that sodium phytate, sepimax zen, and allantoin are the only older ingredients that I have because it takes me so long to go through them. Could the sodium phytate be the issue here? Maybe it has lost its chelating properties? I’m not really sure if that would cause a rancid odor though, and the color/appearance of the final product has not been affected.

  • PhilGeis

    Member
    July 5, 2025 at 4:49 am

    Check for micro contamination. Even if clean, your product is very poorly preserved.

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