Modifying Serum Formula: Adding Extracts & Changing Preservative

Regarding the serum formula from the link you provided:

Adding additional extracts or changing the preservative is possible, but it requires careful consideration as it can significantly impact the final product.

Here are some points to consider:

• Adding Extracts: Adding more active ingredients or extracts can affect the stability of the serum (e.g., cause separation, cloudiness, or precipitation). It can also alter the pH, viscosity, and overall feel. Furthermore, some ingredients may interact with each other, potentially reducing their effectiveness or causing irritation. You need to consider the maximum recommended usage percentage for each new extract and the total percentage of active ingredients in the formula.
• Changing Preservative: Preservatives are essential for preventing microbial contamination and ensuring the safety and shelf life of the product. Different preservatives have different strengths, weaknesses, optimal pH ranges, and compatibility issues with other ingredients. Simply swapping one preservative for another without proper knowledge can result in inadequate preservation, leading to bacterial or fungal growth.

Recommendation:

If you decide to modify the formula, it is highly recommended to:

• Start with small test batches.
• Observe the stability of the modified formula over time (check for changes in color, odor, clarity, and separation).
• If possible, perform basic challenge testing to ensure the new preservative system is effective.
• Be aware that changing ingredients can alter the efficacy and safety profile of the original formula.

It's always best to have a good understanding of cosmetic chemistry principles or consult with someone experienced in formulation before making significant changes to a recipe.