What it is: Improve skin's radiance and hydration levels with Mario Badescu's potent, 7.5% ascorbic acid formula.Who it's for: Ideal for combination, dry or oily skin.What it does: Skin tone will become more even from the brightening effects of the antioxidant vitamin C, while skin's texture is left soft and smooth from the anti-aging powers of collagen and hyaluronic acid.How to use: Apply 3-4 drops on clean skin every other evening. May be used under moisturizer or alone. Brand: Mario Badescu. Style Name:Mario Badescu Vitamin C Serum. Style Number: 253610. Available in stores.