This is “man made” Vitamin E acetate (dl-tocopheryl acetate). It is used just like natural source Vitamin E (it is commonly used in vitamin supplements) and is completely pure. As the acetate form, Vitamin E acetate is very stable, as it will not react with oxygen. Hence, it will last for years in cosmetic preparations. 

Vitamin E acetate is metabolised back to active Vitamin E once it is absorbed by cells in the epidermis. Vitamin E acetate is an excellent moisturising and hydrating agent. It penetrates into the epidermis and serves to bind water in the skin.