What it is: Cutting-edge serum that contains the highest concentration of powerful active ingredients in their purest and most advanced form. It can be used alone or with a moisturiser and mask. What it does: ? Contains 1% AA2G which is the most advanced and stable form of vitamin C. ? AA2G will remain active on the skin for 8 days after application. ? Appropriate for daily use and treatment of photoaging. ? Great serum to be used prior to the Retin C 24hr Cream.