What oily compound found in shark liver oil is used in cosmetics and vaccines? The compound is squalene.
Squalene is a colourless oil and a triterpene with the chemical formula C30H50. It was first associated with shark liver oil, which explains its name: Squalus is a genus of sharks. In many shark species, squalene is a major component of the liver oil that helps provide buoyancy because sharks lack swim bladders.
In cosmetics, squalene can support skin lubrication and barrier care. It is also used in some vaccine adjuvant formulations, including oil-in-water emulsions such as MF59. Strictly speaking, squalene itself is an ingredient in these formulations rather than a complete vaccine or always the adjuvant by itself.
A modern conservation concern is sourcing. Squalene can be obtained from shark liver, but plant-derived and biotechnology-based alternatives are also available. “Squalane” is a related, hydrogenated and more stable derivative commonly used in skincare, so the two names are related but not identical.