Vitamin A is a fat-soluble vitamin found in nature in the form of retinol, in its equivalent retinoid (animal origin) form or as pro-vitamins (plant origin) called carotenoids. The latter are transformed into vitamin A in the liver.
Vitamin A is essential not only for the mechanism of vision but also for cell differentiation. For this reason it is necessary for the growth, the reproduction and the integrity of the immune system.
Retinol is obtained naturally from our diet. Foods rich in vitamin A include animal liver and cod liver oil, eggs and dairy products; large amounts of carotenoids are found in yellow-orange fruits and vegetables (tomato, carrot, pepper, pumpkin, apricot) and in some green leafy vegetables (lettuce, asparagus, broccoli).
Topical vitamin A treatments in the form of retinol are highly effective for promoting cellular turnover and epidermal renewal to even skin tone and diminish the signs of both intrinsic and extrinsic skin ageing.
Vitamin A is recognised as one of the best active ingredients to fight all signs of ageing, but also those caused by photo ageing due to UV exposure. It effectively neutralises the molecule, which gives rise to the formation of free radicals, the main trigger for skin ageing. Most importantly, it encourages cell turnover and facilitates the removal of dead cells, leaving space for the underlying, younger skin. This also helps to prevent the accumulation of melanin: the dark spots are kept under control whilst the existing ones are lightened.
As retinol is also photosensitising, it is recommended that a broad-spectrum sun protection is used as part of any skincare regime.
For retinol to be topically effective, it must reach a concentration of at least 0.6% in the skin.
ZO Skin Health and Medical use a 1.0% concentration of retinol.