Cosrx The Vitamin C 23 Serum blends vitamin C with glutathione to address hyperpigmentation and brighten dull skin while reducing the look of fine lines. It also contains hyaluronic acid and niacinamide for hydration and even tone. The fragrance-free formula is suitable for daily use in the morning with sunscreen. Shake gently, apply a few drops to the skin, and massage from the center of the face outward. Patch test before first use. Not recommended during pregnancy or breastfeeding. 20 g bottle.