The COSRX The Vitamin C 13 Serum is a skincare product formulated with the active ingredient L-ascorbic acid, also known as Vitamin C. L-ascorbic acid is a powerful antioxidant that aids in neutralizing free radicals on the skin, which helps to prevent oxidative stress and reduce signs of aging. When applied topically, L-ascorbic acid penetrates into the skin and undergoes enzymatic conversions to its biologically active form, ascorbate. Ascorbate plays a crucial role in collagen synthesis, thereby promoting skin elasticity and firmness. Additionally, Vitamin C inhibits the enzyme tyrosinase, which is involved in melanin production, leading to a brightening effect on the skin. The serum also contains ingredients such as niacinamide and adenosine, which further enhance the antioxidant properties of Vitamin C and promote skin repair and renewal. Niacinamide, a form of Vitamin B3, helps to strengthen the skin barrier and reduce inflammation. Adenosine, a nucleoside, has anti-inflammatory and wound-healing properties, contributing to overall skin health. The pH of the COSRX The Vitamin C 13 Serum is typically around 3.0 to 4.0, which is optimal for stability and efficacy of L-ascorbic acid. The serum has a light texture and is easily absorbed into the skin, making it suitable for daily use.