There are 2 standards of quality for fish oils according to level of oxidation (TOTOX)
1. FF oil (Functional Food oil), a fresh oil used in food products. It has no smell or taste of fish and has TOTOX less than 5.
2. DS-oil (Dietary Supplement oil), an oil of a poorer quality which is used in health supplements and may have TOTOX up to 130.
Low oxidation – high bioavailability
Natural fresh fish oil has a higher bioavailability and better medical effect than concentrates and artificial ethyl esters. Read the full report is only in Norwegian (RUBIN report 196/2011)
The lower – the better. Fish oils with TOTOX over 10 will smell and taste rancid.