Storage and Shelf Life of Pre-mixed Vitamin C Serum with Vitamin E

Regarding your pre-mixed Vitamin C kit with Vitamin E, even though it contains a preservative, refrigeration is highly recommended for optimal stability and shelf life.

Here's why:

• Vitamin C Instability: L-Ascorbic Acid (the most common form of Vitamin C in serums) is highly unstable and prone to oxidation when exposed to air, light, and heat. Oxidation degrades the Vitamin C, making it less effective.
• Preservatives vs. Oxidation: Preservatives prevent microbial growth (bacteria, mold, yeast), but they do not prevent the chemical oxidation of Vitamin C.
• Refrigeration Slows Degradation: Storing the serum in the refrigerator significantly slows down the oxidation process, helping to maintain the potency of Vitamin C for a longer period.
• Vitamin E's Role: Vitamin E is often included because it's an antioxidant itself and can help stabilize Vitamin C, but refrigeration is still the best way to extend its life.

Shelf Life Estimates (General):

• Refrigerated: Typically lasts several months (e.g., 3-6 months or even longer depending on the specific formula and packaging).
• Room Temperature (without refrigeration): The shelf life is significantly reduced. It might start losing potency or show signs of oxidation (turning yellow/orange/brown) within a few weeks to a couple of months, especially in warm or humid environments.

Recommendation:
For best results and to ensure the product remains effective, it is strongly advised to store the Vitamin C serum in the refrigerator. If you cannot refrigerate it, try to keep it in a cool, dark place away from direct sunlight and heat. Be mindful of changes in color or smell, as these are indicators of oxidation. The manufacturer's instructions on the packaging should be followed if available.

Storing at room temperature will likely cause the product to degrade faster than intended, reducing its benefits.