Issues with Stabilized Vitamin C Serum: Crystallization and Color Change
Question
I purchased Stabilized Vitamin C (Natural-C Glycol™) Serum about 3 months ago. I have two questions regarding its appearance under different storage conditions:
- Refrigerated Storage: I stored the serum in the refrigerator (chilled) continuously. When I took it out to use, I noticed small white crystals appearing, although not in large amounts. Is this precipitation, or is it a normal occurrence? I have transferred the serum to an opaque plastic pump bottle.
- Room Temperature Storage: I had some serum left in the original bottle provided by the company and kept it at room temperature (in an air-conditioned bedroom all day). When I opened it, the serum's color had changed from clear light yellow, as it was initially, to an orange-yellow color. Is this abnormal? Does this mean it has spoiled? The product packaging stated a shelf life of 180 days, but it has only been 3 months, and the serum's color has already changed. (I don't have photos, I discarded the bottle.)
Answer
Questions about Stabilized Vitamin C (Natural-C Glycol™) Serum
Regarding your questions about the Stabilized Vitamin C (Natural-C Glycol™) Serum:
White crystals in refrigerated serum: The product description mentions that for long-term storage, it should be kept in the refrigerator at 6-8°C and away from light. While refrigeration helps maintain stability, sometimes cold temperatures can cause certain components in a serum to crystallize or precipitate. The appearance of small white crystals, especially if not in large amounts, could be a result of this and might not necessarily indicate the product is spoiled, but it's not explicitly mentioned as a normal occurrence in the description.
Color change in room temperature serum: The product is described as a "Light yellow clear liquid". Vitamin C (L-Ascorbic Acid), which is the active component in this serum, is highly sensitive to light and air. Exposure to these factors can cause it to oxidize, which typically results in a color change from light yellow to a darker yellow, orange, or even brown. Although the product can be stored at room temperature, it must be kept away from light, ideally in opaque packaging. A change in color to orange-yellow, even after only 3 months and stored in an air-conditioned room, is a strong indication that the Vitamin C has oxidized and degraded. Once Vitamin C oxidizes, it loses its effectiveness.
In summary, the color change in the serum stored at room temperature suggests it has likely degraded due to oxidation. The white crystals in the refrigerated serum might be a minor temperature-related effect, but the color change is a more definitive sign of instability.
