Serum Formulation Feedback

Thank you for sharing your serum formulation for skin brightening and hydration. It contains a good combination of active ingredients targeting these concerns.

Evaluation of Ingredients

• Whitening Agents: Your formula includes a potent blend of whitening agents: Nicotinamide (Vitamin B3), n-acetyl glucosamine, Activated Resorcinol, and Phenylethyl Resorcinol. Nicotinamide and n-acetyl glucosamine work synergistically for brightening and hydration. Activated Resorcinol and Phenylethyl Resorcinol are also effective tyrosinase inhibitors. While this combination is powerful, using Activated Resorcinol at the maximum recommended level (1%) alongside other potent brighteners might increase the risk of skin irritation. Consider evaluating the tolerance of the final product or potentially adjusting the concentrations.
• Hydration: The inclusion of 1,3-Propanediol, Glycerin, Sodium Hyaluronic Acid (Double Hyaluron Liquid), Nicotinamide, n-acetyl glucosamine, and Allantoin provides excellent hydration and soothing properties.
• Vitamin B6: Vitamin B6 is beneficial for oil control and pore appearance, but its stability is sensitive to pH (stable at pH 2-6) and it degrades with heat and light. This needs careful consideration during manufacturing and when adjusting the final product pH.
• Preservation: Microcare PHC is a suitable preservative for this type of formula, effective in the recommended pH range.
• Stability: Disodium EDTA is correctly included to chelate metal ions and improve overall formula stability.

Emulsifier Recommendation

You are correct that an emulsifier is needed to incorporate the Olive Oil and Sweet Almond Oil into the water-based serum base. Since you have an oil phase (5%) dispersed in a water phase, you need an Oil-in-Water (O/W) emulsifier suitable for a serum texture.

Based on the available options, an emulsifying gelling agent would be a good choice for creating a stable serum texture. Products like CreamMaker EG™ or Sucrose Cream Maker™ are suitable O/W emulsifiers that can help stabilize the oil phase within the water base and contribute to the desired serum consistency.

Alternatively, you could use a combination of a traditional O/W emulsifier (like Olivem 1000) and a thickener (like Sepimax Zen) to achieve the desired texture and stability.

pH Consideration

The stability and efficacy of several ingredients, particularly Vitamin B6 (stable pH 2-6), Activated Resorcinol (optimal pH 4.5-5.5), Phenylethyl Resorcinol (optimal pH 4-5), and Microcare PHC (pH 4.0-7.0), depend on the final pH of the formula. Aiming for a pH range between 4.5 and 5.5 would likely provide the best balance for the stability and efficacy of most active ingredients and the preservative.

Manufacturing Notes

• Ensure Vitamin B6 is added without heat and protected from light during the process.
• Activated Resorcinol and Phenylethyl Resorcinol are oil-soluble and light-sensitive. They should be incorporated carefully, potentially in the oil phase or added at a later stage, avoiding excessive heat and light exposure. Packaging in opaque containers is recommended.
• Follow the specific mixing instructions for your chosen emulsifier/thickener.

Overall, this is a comprehensive formula. Adding a suitable O/W emulsifier and carefully controlling the pH and manufacturing process will be key to its stability and effectiveness.