Garnier Skin Naturals, Face Serum, Increases Skin's Glow Instantly and Reduces Spots Overtime, Bright Complete Vitamin C Booster. Bright Complete Vitamin C Booster Face Serum is Garnier's most concentrated brightening formula yet. Compared to our day cream, this serum is enriched with 30 times the amount of Vitamin C! Together with the lemon extract, this lightweight, non-oily formula penetrates the skin to instantly increase its glow as well as reduce dark spots in a safe and natural way!