Ascorbic Acid (Vitamin C)
Why is L-ascorbic acid a vitamin? Most animals can make their own vitamin C, but humans can’t. Somewhere along the line we lost a crucial enzyme, L-gulonolactone oxidase, required for the synthesis of L-ascorbic acid, making it an essential nutrient (i.e. we must get it by eating food containing it, or applying the vitamin to our skin).
L-ascorbic acid is important for plants and animals because it works as an antioxidant. More specifically, it is a water soluble antioxidant, and this means that it can work in almost all the reactions occurring in the cell. It also promotes elasticity and collagen synthesis, reduces free radicals formed by the sun and helps eliminate the formation of dark spots.