As an antioxidant, vitamin C is a key ingredient to keep your skin looking bright and youthful. First, it helps protect against harmful free radicals by neutralizing them which, in turn, helps to decrease the visible signs of aging on your face  such as fine lines, wrinkles, dark spots from sun damage, and loss of moisture. But the most notable and popularized benefit of vitamin C is its ability to brighten your face and diminish any discoloration.