Using Sodium Metabisulfite and Phenoxyethanol Together

Sodium Metabisulfite and Phenoxyethanol serve different functions in a cosmetic formulation and can be used together at their respective recommended concentrations.

• Sodium Metabisulfite: This is primarily used as an antioxidant to help maintain the quality and stability of other ingredients in the formula. The recommended usage rate is 0.1-0.2% (with 0.2% being recommended).
• Phenoxyethanol: This is used as a preservative to prevent the growth of bacteria and fungi, thus extending the product's shelf life. The recommended usage rate is 0.5-1.0% (for eye products, use no more than 0.5%).

When using them in the same product, you would incorporate each ingredient at its recommended rate based on the total weight of your formulation. Sodium Metabisulfite is typically mixed into the water phase, while Phenoxyethanol can be mixed in at any step, provided the temperature is below 80°C and the pH is between 2-9.

Remember that the effectiveness of preservatives can vary depending on the specific formula. It is always recommended to perform a challenge test on your final product to ensure the preservative system is effective.