Questions on Modifying and Storing Vitamin C E Ferulic Formula

Question

Regarding the Vitamin C E Ferulic formula:

If I want to reduce stickiness, can I use Panthenol (Vitamin B5) ExtraLite instead of Panthenol (Pro-Vitamin B5)?
(Based on the information, the suitable pH range is 4.0-7.0)
If I add Glutathione (L-Glutathione Reduced) to the provided formula, will the efficacy improve? And how and at what step should it be mixed?
For the preservative Phenoxyethanol, it is mentioned that it can be mixed with a Preservative Booster (performance enhancer for preservatives) at "0.3% Phenoxyethanol + 3% pentylene glycol". My question is: What is a Preservative Booster? How is it used? Is it available for sale?
If I want to mix a large amount (500 ml) of this Vitamin C formula, how should I store it better?
Between:
- Store in an amber glass bottle in the refrigerator. When needed, transfer a small amount to a smaller bottle.
- Transfer to small bottles immediately after mixing and store at room temperature.

MySkinRecipes Expert · Accepted Answer

Answers Regarding the Skinceuticals C E Ferulic Formula

Here are the answers to your questions about modifying and storing the Vitamin C E Ferulic formula:

Reducing Stickiness with Panthenol Substitution: Yes, you can replace the standard Panthenol (Vitamin B5) with Panthenol (Vitamin B5) ExtraLite to potentially reduce the stickiness of the formula. The staff confirmed this substitution is possible.
Adding Glutathione: According to the staff, adding Glutathione (L-Glutathione Reduced) to this formula is not considered necessary for a significant improvement in efficacy. The potential small benefit may not justify the increased cost.
Preservative Booster: A Preservative Booster is an ingredient that enhances the effectiveness of preservatives, allowing for lower concentrations of traditional preservatives to be used while maintaining microbial protection. In the context you mentioned, Pentylene Glycol can act as a booster for Phenoxyethanol. The staff recommended using 3% 1,2-Hexanediol as a sufficient alternative preservative booster. 1,2-Hexanediol is available and can help control germs effectively, even allowing for reduced use of other preservatives like Phenoxyethanol.
Storing a Large Batch (500 ml) of Vitamin C Formula: For storing a large volume of this Vitamin C formula, the best method to extend its shelf life is to store it in an amber glass bottle in the refrigerator. When you need to use it, pour a smaller amount into a separate small bottle for daily use. Storing the bulk in the refrigerator protects it from light, air, and heat, which degrade Vitamin C. This method is significantly better for preservation than dividing the entire batch into small bottles and keeping them at room temperature.