Garden of Wisdom Vitamin C 23% + Ferulic Acid Serum provides high strength pure L-ascorbic acid to brighten and even out skin tone whilst Ferulic acid helps protect skin against free radical damage. Vitamin C or specifically L-ascorbic acid, L-AA, is a powerful antioxidant with credible body of research supporting its skin benefits. Vitamin C has been shown to defend skin from free radical damage caused by UV exposure whilst enhancing the production of collagen. L-AA antioxidant powers also help prevent the oxidation of melanin, skin's natural pigment, resulting in a clearer, brighter and more even skin tone. Vitamin C serum also helps to inhibit the production of skin pigment, melanin, and is so used to prevent and treat hyperpigmentation. Ferulic acid is a powerful antioxidant found in the cell walls of plants. Ferulic acid not only protects vitamin C against oxidation but has been found to be destroying the superoxide and hydroxyl radicals thus helping to protect skin against ageing. Ferulic acid is particularly beneficial for protecting skin against sun damage. pH range of 3.1 - 3.4.