Formulation Review and Storage Advice

Based on your revised formula and questions, here is the information you requested:

Mixing Steps Confirmation

Your proposed mixing steps for the revised formula are appropriate for creating a water-based serum or light cream. Here's a breakdown:

1. Combine the water-soluble ingredients (Beta Glucan, Green Tea Extract, Natural Moisturizing Amino Acids, Glucosamine (N-acetyl-D), Vitamin B3, Pep®-Coll, Alpha Arbutin, licorice, Allantoin) with the water. Stir until everything is fully dissolved. Note that some ingredients like Beta Glucan may disperse rather than dissolve completely clear.
2. Add the Light Cream Maker and mix thoroughly to develop the desired cream texture. Ensure adequate mixing to avoid a flaky texture.
3. Incorporate the preservative (Phenoxyethanol) and mix well.
4. Finally, check the pH of the mixture and adjust it to 6 using Lactic Acid.

When mixing, be mindful of temperature restrictions for some ingredients to maintain their efficacy. For example, Pep®-Coll and Green Tea Extract should be added when the temperature is below 40°C, and Alpha Arbutin below 30°C. Light Cream Maker is a cold-process emulsifier.

Refrigeration

Yes, refrigerating the finished product is a good practice, especially since your formula contains sensitive active ingredients like Pep®-Coll, Alpha Arbutin, Green Tea Extract, and Licorice Extract. Product descriptions for these ingredients often recommend refrigeration for long-term storage to help maintain their stability and potency over time.

While Allantoin's solubility is lower at cold temperatures (around 0.2% in water at 6-8°C), using 0.3% in the overall formula is unlikely to cause significant issues upon refrigeration, particularly if it was fully dissolved during mixing. The benefits of refrigerating to preserve the efficacy of other key actives generally outweigh this minor consideration.

Shelf Life of Pep®-Coll at Room Temperature

The product description for Pep®-Coll states that for long-term storage, it should be kept in a refrigerator at 4-8°C and has a shelf life of at least 24 months under these conditions.

If the product is stored at room temperature (away from direct sunlight and heat), the overall microbiological stability with the preservative (Phenoxyethanol) might be around 6-12 months or longer if stored correctly. However, the efficacy of the peptide (Pep®-Coll) itself will likely degrade faster at room temperature compared to refrigerated storage. While it might still provide some benefit, its full potency is best maintained when kept cool. For optimal results, refrigeration is recommended.

Your revised formula appears well-suited for addressing skin barrier strength, hydration, and dark spots, as discussed in the previous replies.