Regarding Mixing Vitamin C Ester and Vitamin B3

Based on the information provided:

• Mixing Vitamin C Ester and Vitamin B3 (Niacinamide) in a formulation does not cause harm to the skin.
• The main concern is that the effectiveness of the ingredients may be reduced.
• Specifically, the Vitamin C Ester may degrade faster than it normally would.
• You can observe potential degradation by checking if the mixture changes to a dark yellow color. (A light yellow color is normal).
• Since the mixture is not harmful, you can continue to use it. However, please be aware that the expected benefits might be less pronounced due to the reduced efficacy of the ingredients.