Stabilized Vitamin C pH Adjustment and Stability for FDA Registration
Question
Regarding the ingredient Stabilized Vitamin C (Natural-C Glycol™) which has an original pH of 2-3:
- For cosmetic registration with the FDA, the pH needs to be at least 3.5.
- The manufacturer states that mixing additional ingredients is not recommended as it may affect stability.
If the pH is adjusted upwards to 3.5 or 4 to meet FDA requirements, will this adjustment affect the effectiveness and stability of the Stabilized Vitamin C?
Answer
Vitamin C Stability and pH Adjustment for FDA Compliance
Regarding your question about adjusting the pH of Stabilized Vitamin C (Natural-C Glycol™) from its original pH of 2-3 to meet the FDA requirement of at least 3.5 for cosmetic registration, and whether this affects its effectiveness:
- Product pH: Stabilized Vitamin C (Natural-C Glycol™) is supplied with a pH in the range of 2-3.
- FDA Requirement: For cosmetic products, the FDA typically requires a pH of at least 3.5 for registration.
- Stability Concern: The product description for Natural-C Glycol™ explicitly states that it is not suitable for mixing any additional ingredients as this may affect the stability of the vitamin C. The company cannot guarantee stability if additional ingredients are mixed without consulting their R&D team.
While adjusting the pH upwards to 3.5 or 4 would meet the FDA requirement, based on the manufacturer's information, adding ingredients to raise the pH could potentially compromise the stability of the Stabilized Vitamin C. L-Ascorbic Acid is generally more stable at lower pH levels. Therefore, increasing the pH, even to 3.5 or 4, might reduce the stability and effectiveness that the product is designed to provide, contrary to the benefit of it being a "Stabilized" form, especially if not done with expert formulation knowledge.
It is recommended to adhere to the manufacturer's guidance regarding not mixing additional ingredients or to consult their R&D team if pH adjustment is necessary for regulatory compliance.
