Shark Liver Oil

Squalene accumulates at the greatest concentrations in the skin, where it appears to play a vital role in quenching free radical oxygen (oxygen singlets), preventing the harmful effects of lipid peroxidation. Adequate concentrations of squalene in the skin prevent oxidative damage from ultraviolet light.
Squalene also appears to play a similar role in the retina, where it is known to play some kind of important function.
A significant body of evidence indicates that reasonable doses of supplemental squalene prevents the chemical initiation of some kinds of cancers, and promotes the regression of some kinds of preexisting tumors.
One animal study found that a 1% squalene diet reduced a certain type of colon cancer foci by 46%. Another study found that squalene as 2% of the diet made animals resistant to the toxic effects of whole-body gamma radiation.1