Shark liver oil (SLO) is the oil obtained from the livers of sharks, primarily Centrophorus squamosus, Cetorhinus maximus, and Squalus acanthias, or deep-sea shark, basking shark, and dogfish shark, respectively.

It has been long used in Scandinavian folk medicine to treat multiple ailments, including wounds, cancer, heart disease, and infertility (1Trusted Source).

Nowadays, it’s sold as a dietary supplement that promises to deliver these same health effects.

Research on SLO attributes its multiple health benefits to its high alkylglycerol (AKG), squalene, and omega-3 polyunsaturated fatty acid (PUFA) content (2Trusted Source).

The oil has a dark yellow to brown shade and pungent aroma and taste.

You may find SLO in liquid or capsule form, or as an ingredient in skin creams and lip balms.