I don't know the details of labeling laws, but I believe fish oil is most commonly sold as ethyl esters, and this is called "fish oil concentrate". Free fatty a

I don't know the details of labeling laws, but I believe fish oil is most commonly sold as ethyl esters, and this is called "fish oil concentrate". Free fatty acids are considered a defect in edible oils. They taste rancid and make the oil decay faster. Triglycerides and ethyl esters both get digested in the small intestine by pancreatic lipase enzymes, releasing free fatty acids where you can't taste them. Both raise blood levels of free fatty acids, and the quantity of ethanol released from the ethyl esters is small enough that I think it's very unlikely to matter. But as the article points out, phospolipids get digested differently, and phospolipids are converted to ethyl esters in the transesterification processing too. By focusing only on blood levels of fatty acids, people overlooked a potentially important difference between natural and processed fish oil.