Why Vitamin C Serums Oxidize (Stability, Color Change & What It Means for Your Skin) One of the most common reasons people stop using Vitamin C serums is oxidation. You may have experienced it yourself:a serum that starts clear, then slowly turns yellow, orange, or brown — leaving you wondering whether it’s still safe or … Continue reading Why Vitamin C Serums Oxidize (Stability, Color Change & What It Means for Your Skin)