Squalene was originally derived from shark liver oil. The word is related to the Italian word for shark or squalo and came from the name of the family of deep sea shark that it was originally obtained from, Squalidae. Shark liver oil has been taken for centuries because of it's health benefits, but killing deep sea sharks to obtain their livers is now recognized to be both unethical and unsustainable. Squalene, a triterpene is a precursor for sterol synthesis including cholesterol and steroid hormones. Because of this, some worry that squalene will increase cholesterol when in fact the research has shown the opposite. Squalene has been shown to decrease total cholesterol, LDL cholesterol(bad) and triglycerides while raising HDL cholesterol(good). When oils are refined, the processing steps each reduce the amount of remaining beneficial squalene which is why extra-virgin olive oil is one of the best vegetable sources of squalene in the diet.