Squalene is a natural organic compound originally obtained for commercial purposes primarily from shark liver oil, though there are botanic sources as well, including amaranth seed, rice bran, wheat germ, and olives. All higher organisms produce squalene, including humans. It is a hydrocarbon and a triterpene.

Role in steroid synthesis

Squalene is the biochemical precursor to the whole family of steroids^[1] Oxidation (via squalene monooxygenase) of one of the terminal double bonds of squalene yields 2,3-squalene oxide which undergoes enzyme-catalyzed cyclization to afford lanosterol, which is then elaborated into cholesterol and other steroids.

Shark squalene

Squalene is a low density compound often stored in the bodies of cartilaginous fishes such as sharks, which lack a swim bladder and must therefore reduce their body density with fats and oils. Squalene, which is stored mainly in the shark's liver, is lighter than water with a specific gravity of 0.855. Environmental and other concerns over shark hunting have motivated its extraction from vegetable sources instead.

Recently it has become a trend for sharks to be hunted to process their livers for the purpose of making squalene health capsules. However, there is little clinical evidence to prove that, taken internally, squalene does anything to increase an individual's quality of life.

Use as a moisturizer

Squalene is used in cosmetics as a natural moisturizer. It penetrates the skin quickly, does not leave a greasy feeling on the skin and blends well with other oils and vitamins.

Biosynthesis

• Two molecules of farnesyl pyrophosphate condense with reduction by NADPH to form squalene - by squalene synthase;

References

1. ^ K. Bloch:"Sterol structure and membrane function",CRC Crit. Rev.,14:47-92.