Lipid

Lipids are molecules that contain hydrocarbons and make up the building blocks of the structure and function of living cells.  Lipids are in all living cells. In the nail plate during the process of keratinisation where the living cells loose all their cellular contents to be replaced by keratin, the lipids are pushed out and form an efficient protection and lubrication between the nail plate cells. These can be lost by environmental factors and lack of them can result in brittle nails.