Formulation Review: Azelaic Acid, Hi-Quercetin, Allantoin, Pro Polymer Gel/Serum

Based on the staff's feedback regarding your proposed formula, here are the points to consider for its usability:

• Azelaic Acid 20%: This concentration is higher than the recommended maximum of 10%. It should be reduced.
• Hi-Quercetin® (Onion Extract) 10%: This is the maximum recommended usage rate. The staff notes that this concentration may cause the skin to appear yellowish, making it more suitable for nighttime use.
• Allantoin 0.5%: The staff clarifies that the 0.5% usage rate for Allantoin should be based on the amount of water in the formula, not the total formula weight.
• Pro Polymer 1%: This amount is likely insufficient to thicken the formula, especially with a high concentration of Azelaic Acid which can reduce viscosity. The staff recommends starting with 2% Pro Polymer and adjusting as needed to achieve the desired gel texture.
• Preservative: The formula currently lacks a preservative, which is necessary for product stability and safety. The staff recommends adding one.

In summary, while the ingredients are generally compatible, the original formula requires adjustments to the percentages of Azelaic Acid, Allantoin, and Pro Polymer, and the addition of a preservative, to be considered usable and stable according to the staff's recommendations.