Vitamin C (ascorbic acid) plays an important role in maintaining skin health and can promote the differentiation of keratinocytes and decrease melanin synthesis, leading to antioxidant protection against UV-induced photodamage.
The Role of Vitamin C in Skin
Vitamin C is involved in the formation of the skin barrier and collagen in the dermis and plays a physiological role in the skin against skin oxidation, in antiaging of wrinkles, and in cell signal pathways of cell growth and differentiation, which are related to the occurrence and development of various skin diseases (Ponec et al., 1997b). Vitamin C has a dual role of antioxidation and pro-oxidation, and this role maintains the balance of the two reactions in the body (Kim K. et al., 2015). Ascorbic acid and transition metals, such as Fe2+, produce reactive oxygen species (ROS) outside of the cell, and high levels of ROS can destroy the antioxidant defense system of cancer cells (Ohno et al., 2009; Conner et al., 2012) because the antioxidation system of tumor cells is incomplete and its balance is destroyed (Kim K. et al., 2015; Uetaki et al., 2015). High levels of Vitamin C in the cells lead to oxygen-promoting reactions, which cause DNA damage, the depletion of ATP reserves, and failure of cellular metabolism (Tian et al., 2014). Vitamin C is also involved in resistance to UV-induced oxidative stress, inhibition of melanogenesis, and promotion of the differentiation of keratinocytes and has been used for a long time as a clinical treatment reagent. Vitamin C deficiency leads to many systemic diseases in humans and causes scurvy in the world’s navies (Carpenter, 2012).