Suitability of Preserve-BSB™ for Lip Serum Formulations

Preserve-BSB™ (eq. Optiphen BSB-W) can be used in a lip serum, but its suitability depends on the type of formula you are creating. Here are the key factors to consider:

1. Formula Type (Water-Based vs. Oil-Based)

• Water-Based Serums: This preservative is water-soluble. It is ideal for lip serums that contain water, such as gel-based serums or emulsions (creams/lotions).
• Oil-Based Serums: If your lip serum is 100% oil (anhydrous), this product is not suitable because it will not dissolve in the oil.

2. pH Requirement (Critical)

For this preservative to be effective, the final pH of your lip serum must be 5.5 or lower (ideally between 4.5 and 5.5). If the pH is higher than 5.5, the organic acids (Sodium Benzoate and Potassium Sorbate) will not be able to protect the product from mold and bacteria.

3. Usage and Sensory Experience

• Usage Rate: Recommended at 0.3–1.0%.
• Taste/Scent: It contains Benzyl Alcohol, which has a mild characteristic scent and can sometimes have a slightly bitter taste. Since lip products are applied to the mouth, you should test the sensory profile of your final formula to ensure it is acceptable.
• Safety: It is globally approved for leave-on products and is considered a "nature-identical" preservative system, making it a good choice for natural-focused branding.

Summary

If your lip serum contains water and you can maintain a pH below 5.5, Preserve-BSB™ is an excellent, broad-spectrum choice. If your serum is purely oil-based, you should look for an oil-soluble preservative or an antioxidant (like Vitamin E) instead.