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
While the oils of olive, palm, wheat-germ, amaranth, and rice bran contain some squalene, none match the squalene content of shark liver oil, after (the latin name of) which squalene is named.
Shark liver oil, like cod liver oil, contains the same benefits as cod liver oil, such as vitamins A and D, and omega-3 fatty acids, but its high squalene content as well as its alkoxylglycerol content make it an even more prized supplement to a healthy diet.
Many people find that shark liver oil boosts their immune system and increases the health of their skin, and some researchers suggest it has cancer-preventative properties because of its high squalene content.