As a person ages, hormonal changes cause intrinsic aging, while the external environment, primarily ultraviolet (UV) radiation, accounts for much of the extrinsic aging. Intrinsic aging of the skin results in the thinning of the epidermis, a reduction in the connective tissue matrix, and a reduction in sebaceous glands. Therefore, even without UV radiation exposure, as a person ages, their skin will look thinner, paler, more wrinkled, and drier. Genetically, men have a thicker epidermis, connective tissue matrix, and higher sebaceous gland density, therefore the signs of intrinsic aging tend to be less pronounced compared to a woman of the same age.

UV radiation leads to extrinsic skin aging by inducing the production of reactive oxygen species (ROS) in the skin. In time the ROS generate a cascade of molecular reactions that result in mutation and destruction of collagen, elastin, proteoglycans, and other dermal cellular structures. Macroscopically, this ROS-induced damage will make an individual’s skin look dry, wrinkled, dull, sallow, and unevenly pigmented. UV radiation also triggers melanogenesis, hence resulting in skin darkening and pigment formation.

Vitamin C (Vit C) and glutathione (GSH) are strong antioxidants. Their strong antioxidant property helps to protect the skin against UV radiation induced photoaging by eradicating the ROS, hence halting the destructive cascade of activities. Vit C and GSH also help to whiten the skin by inhibiting melanogenesis, triggered by UV radiation. Vitamin C also triggers a strong reparative effect in the skin by inducing a quantitative increase and qualitative improvement of collagen molecules thereby reversing the UV induced skin damage.

In summary, UV radiation produces ROS and triggers melanogenesis, which causes the skin to become dry, dull, and unevenly pigmented. Vitamin C and glutathione remove the ROS, repair the skin connective tissue, and inhibit skin darkening, thereby making the skin more hydrated, fairer, and more radiant especially on the areas of skin whitening, post-operation wound healing, repair of second and third degree burns, and repair of photo-aged skin.