I know that vitamin c is a great antioxidant and supposed to protect the skin from the UV light. My vitamin c serum is doing the opposite during the daytime. I get darker and a bad suntan and the serum is not going bad. I do wear a high SPF cream. The vitamin C I'm using does have L-Ascorbic Acid, Ethyl ascorbic acid & Ferulic Acid. Does anyone know what vitamin c or derivatives that are best to wear during the day or night?