Homemade Serum Without Preservative: Storage Outside Fridge

Asked by: playplants On: July 06, 2013 Product Type: Cosmetics

Question

Regarding the following homemade serum formula (approximately 60 ml total):

  • Hyaluronic Acid
  • B3
  • Centella Asiatica extract
  • PCA
  • Urea
  • Glucosamine
  • Bisabolol
  • Allantoin
  • Sodium Lactate

I did not use any preservative and have not been refrigerating it recently. I have always stored it in the refrigerator since mixing and during use. Now I have moved to a dormitory without a refrigerator. I took the serum out of the fridge at 7:15 AM, and at the time of typing (2:03 PM), the serum is still in an amber bottle. It appears as a clear liquid with no precipitation. Can I still use it?

Note: I have made two versions of this formula.

Answer

Serum Storage Without Refrigeration and Preservatives

You've made a serum with several beneficial ingredients like Hyaluronic Acid, B3, Centella Asiatica extract, PCA, Urea, Glucosamine, Bisabolol, Allantoin, and Sodium Lactate. You mentioned not using a preservative and previously storing it in the refrigerator.

The key issue here is the absence of a preservative in a water-based formulation (which a serum typically is). Water is essential for microbial growth (bacteria, mold, yeast).

  • Role of Preservatives: Preservatives are crucial in cosmetic products, especially those containing water, to prevent the growth of these microorganisms. Microbial contamination can happen during mixing, transfer, or even from contact with the air or dropper during use.
  • Refrigeration: Storing the serum in the refrigerator significantly slows down microbial growth and helps maintain the stability of some ingredients. However, refrigeration is not a substitute for a preservative for long-term storage, particularly when the product is exposed to room temperature.

Regarding your specific situation:

You took the serum out of the refrigerator several hours ago. While it currently looks clear with no precipitation, this doesn't guarantee it's free from microbial contamination. Microorganisms might be present but not yet visible or causing noticeable changes in appearance within a few hours.

Conclusion:

Without a proper preservative system, storing your serum at room temperature carries a high risk of microbial contamination and growth over time. Even short periods outside the fridge increase this risk. Using a contaminated product can lead to skin irritation, infections, or other adverse reactions.

Therefore, it is not recommended to continue using the serum after it has been stored outside the refrigerator without a preservative, especially for an extended period. For future formulations intended for storage at room temperature, incorporating an effective and appropriate preservative system is essential for safety and stability.

Tags

Microbial Contamination Preservation Serum Stability Storage Conditions