I compare Vitamin C Serum to putting lemon juice onto a cut up apple. It brightens skin and has antioxidant properties. It can brighten the skin through the dermis layer. Vitamin C also helps maintain collagen in our skin. Vitamin B5 protects the skin from oxidative damage to cell membranes. Hyaluronic Acid holds moisture to keep skin hydrated. 3 Ceramides protect our skin barrier.
I can see a change in my skin after 3 days. It is a small, gradual change that only I can recognise. Each day, my skin shows signs of improvement. I believe that a change will be visible to others after a month or so.