Answer: It is bottled in dark amber glass to preserve this high-quality oil so you can bask in its hydrating goodness for up to 18 months.

When shopping for a vitamin C face serum, look for products that contain a high concentration of vitamin C. A 10-20% concentration is considered effective for brightening and evening out skin tone. Just be aware that higher concentrations may not be suitable for sensitive skin types. Vitamin C comes in different forms, including L-ascorbic acid, ascorbyl palmitate, and tetrahexyldecyl ascorbate. L-ascorbic acid is the most common and most effective form, but it can be unstable and prone to oxidizing. Ascorbyl palmitate and tetrahexyldecyl ascorbate are more stable and less likely to oxidize. Vitamin C is most effective at a pH level between 3.5 and 4.5. Look for products with a pH in this range to ensure maximum effectiveness. Many vitamin C face serums contain other beneficial ingredients, such as hyaluronic acid, ferulic acid, and vitamin E. These ingredients can help to hydrate and protect the skin, boost collagen production, and provide antioxidant benefits. Vitamin C is sensitive to light and air, so choosing a serum in a dark, opaque bottle or a pump dispenser to protect it from exposure is important. Avoid products that come in clear or transparent bottles or dropper applicators. Before purchasing, read reviews from other customers to get an idea of the product's effectiveness. Finally, choose a reputable brand with high-quality ingredients and a good reputation in the skincare industry.