Biological waxes are esters of long-chain saturated and unsaturated fatty acids (having 14 to 36 carbon atoms) with long chain alcohols (having 16 to 30 carbon atoms).

Waxes serve a diversity of functions in nature, related to their water repellent properties and their firm consistency. Certain skin glands of vertebrates secrete waxes to protect the hair and skin and to keep the pliable lubricate, and waterproof. In marine organisms that constitute the plankton, waxes are the chief storage form of metabolic fuel.