ABSTRACT
Vitamin A, in its various forms and derivatives, is a common additive in cosmeceutical products. Vitamin A exists in two major forms: retinol and carotenoids. Retinol, also known as preformed vitamin A, is commonly found in nature in animal products, while carotenoids, referred to as provitamin A, are more frequently found in plant products. Retinols can also undergo various conversion reactions resulting in natural derivatives with varying degrees of biological activities, including retinoic acid, retinol, retinaldehyde, retinyl esters, and oxoretinoids. The use of retinol for medicinal purposes dates back to Ancient Egypt, when liver enzymes, which contain high quantities of vitamin A, were used topically to treat night blindness. In the early 1900s, vitamin A in egg yolks was discovered to have an integral role in chick and mice growth and development. Shortly after this, the importance of vitamin A for proper epithelization and gland function was discovered in the mouse model.
