Serum Yellowing Issue

Your serum turned yellow likely due to the degradation of Vitamin C (L-ascorbic acid). L-ascorbic acid is unstable in water and oxidizes over time, causing discoloration.

The combination of Vitamin C (L-ascorbic acid) and Safe-B3™ (Vitamin B3, Niacinamide) in the same formula can also contribute to stability issues and potentially accelerate the degradation of Vitamin C.

Once the serum has yellowed, the Vitamin C has lost significant potency, and the change is irreversible.

Recommendations for Future Formulations

To prevent yellowing and maintain ingredient efficacy:

• Separate Vitamin C (L-ascorbic acid) and Safe-B3™ (Vitamin B3, Niacinamide): Use these ingredients in different products or apply them at different times.
• Use Stable Vitamin C Derivatives: Consider using more stable forms of Vitamin C such as:
  • Sodium Ascorbyl Phosphate (SAP)
  • Magnesium Ascorbyl Phosphate (MAP)
  • Ascorbyl Glucoside
  • Perfect-C™ (Ascorbyl Tetraisopalmitate)
• Adjust L-Ascorbic Acid Formulation: If using L-ascorbic acid, formulate in an anhydrous (water-free) base or at a low pH (below 3.5) to improve stability.
• Optimize Packaging: Use opaque, airless containers to protect the serum from light and air.