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Squalene oil can be of vegetable (olive oil), animal (shark liver oil) or synthetic origin. Controversies exist when squalene is of animal origin, and extracted from the liver of sharks: the animal is killed, its viscera are extracted and its carcass is thrown back into the sea.
When it is of plant origin, squalene can be called phytosqualene. Make sure it is of vegetable origin in your products, do not hesitate to contact the brand to make sure. However, most squalene used today is no longer of animal origin.
Squalene is used primarily as an emollient in many creams. Squalane is a purified and hydrogenated form of squalene, much more used in cosmetics.