Cod liver oil has a long history of use for supporting the heart, brain, and overall health.* Because Nordic Naturals has always used 100% Arctic Cod livers in our CLO formulas (unlike many CLO products on the market, no fish body oils or synthetic additives are ever used), our Arctic CLO formulas have omega-3. And, our CLO is also tested to ensure healthy levels of naturally occurring vitamins A and D. Over the last 10 years, we have perfected our three-step "Gold Standard" system that allows our CLO formulas to surpass all international quality standards and ensure the unparalleled freshness, purity, and sustainability of our CLO formulas.