Nutrition Diagnostics - What is the difference between cod liver oil and fish oil?

Cod liver oil and fish oil aren’t quite the same thing - there are a few key differences. For starters, cod liver oil contains vitamin A and vitamin D, whereas fish oil does not. This is part of the reason that Nutrition Diagnostics favours cod liver oil over fish oil - because we believe it delivers additional benefits. There is also a difference in the way that the oils are extracted. Cod liver oil - as the name suggests - is derived from the liver of the cod fish. Fish oil, on the other hand, is not derived from the liver, but the flesh of the fish.