Shark Liver Oil
Scientific Name(s): Centrophorus squamosus (deep sea shark), Cetorhinus maximus (basking shark), Squalus acanthias (dogfish shark)
Medically reviewed by Drugs.com. Last updated on Nov 1, 2021.
Clinical Overview
Use
Shark liver oil (SLO) has been used to help treat cancer, skin conditions, and respiratory ailments, as well as to reduce recurrent aphthous stomatitis and prevent radiation sickness. However, limited clinical data are available. Alkylglycerols have been studied as an immune system modulator an anti-inflammatory. Animal data suggest SLO may improve fertility.
Dosing
SLO marketed under the name isolutrol has been studied in a clinical trial of acne at a topical concentration of 0.15 g per 100 mL.
Contraindications
Contraindications have not been identified.
Pregnancy/Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking.
Interactions
None well documented.
Adverse Reactions
Few toxic effects have been reported. SLO supplements may have an unpleasant taste and/or odor. There have been reports of SLO-induced pneumonia in humans and pigs.
Toxicology
No adverse reactions or effects on mortality were noted in rats receiving short- and long-term doses of a supercritical fluid extract of SLO at doses 100 to 200 times that of normal human consumption. In Sweden, a SLO product (Ecomer) was prohibited for use by the National Board of Health and Welfare because of suspected adverse effects. A case of acute toxic hepatitis has been reported.
Source
SLO is commercially produced from the livers of several species of deep sea sharks. SLO is a major natural source of squalene and alkyglycerols.Budavari 1989
History
In 1916, squalene was isolated from SLO.Langdon 1953 Initially, SLO was employed by Scandinavian fishermen to treat skin conditions, respiratory ailments, and certain cancers. The oil has been historically used to treat what was referred to as glandular disease that today most likely would be lymphadenopathy.Krotkiewski 2003 The active components, alkylglycerols, have been studied in a number of areas, including use as an immune system stimulant.Pugliese 1998
Chemistry
SLO contains alkylglycerols (AKGs), squalene, pristane, vitamins A and D, esters of fatty acids, glycerol ethers, triglycerides, cholesterol, and fatty acids.Budavari 1989 The composition of SLO differs among shark species and depends on the size of the shark (the liver constitutes about 25% of the total shark body weight),Budavari 1989diet, gender, growth rate, swimming depth, and reproduction.Davidson 2007 Alkylglycerols are a group of ether-linked glycerols found in a number of shark species. For example, 1-O-(2-hydroxyalkyl) glycerols, 1-O-(2-methoxyhexadecyl)-glycerol, 1-O-(2-methoxy-4-hexadecenyl)-glycerol, and 1-O-(2-methoxy-4-octadecenyl)-glycerol have been isolated from Greenland SLO.Hallgren 1974, Hallgren 1967 Dogfish shark liver contains 40% to 70% SLO, of which 30% to 40% are 1-O-alkyl diacylglycerol ethers.Kang 1997 Purification and characterization of deep sea SLO 1-O-alkylglycerols have been performed. The oil contained glycerol esters and 60% unsaponifiable matter, including squalene (45%) and cholesterol (4.5%).Bordier 1996 Between 60% to 90% of liver weight in Centrophorus species is squalene-rich oil, which increases in concentration with the age of the shark. More than 50 fatty acids have also been identified.
