Ascorbic acid is one of the main non-enzymatic, water-soluble antioxidant. Vitamin C is required for the synthesis of collagen, an important structural component of blood vessels, tendons, ligaments and bones.

In addition, vitamin C is required for the synthesis of carnitine, a small molecule that is essential for the transport of fat to ce- llular organelles called mitochondria, for conversion to energy.

It plays a critical role in dermal construction, stimulating collagen synthesis of dermal fibroblasts. This is thought to occur as a result of ascorbate directly stimulating collagen synthesis, directly and specifically activating collagen gene regulation both by increasing the transcription rate and stabilizing procollagen messenger RNA, thus genetically signaling collagen synthesis. Another mechanism is the initiation of lipid peroxidation, which leads to an increase in a by-product, which stimulates collagen gene expression.

In addition, ascorbic acid is necessary to form lysyl hydroxylase, an enzyme necessary for cross-linking one collagen molecule to another, providing tissue strength.

The topic use of ascorbic acid prevents and treats photo-ageing. UV light exposure depletes up to two thirds of cutaneous ascorbic acid stores.