Fish oil supplements with higher concentrations of EPA and DHA tend to cost more, but paying more does not guarantee the product is less oxidized or more stable once you account for the actual EPA and DHA content.

We analyzed the available evidence and found that the price of fish oil supplements is not a reliable indicator of their oxidation levels. While supplements with higher concentrations of EPA and DHA often cost more, paying a higher price does not mean the product is less oxidized or more stable once you account for the actual EPA and DHA content [1]. What we’ve found so far suggests that cost may reflect factors like brand, marketing, or ingredient concentration, but not necessarily freshness or resistance to spoilage. Oxidation refers to when the oil breaks down due to exposure to air, light, or heat — a process that can reduce effectiveness and create unpleasant tastes or odors. Even expensive products can show signs of oxidation if they’re poorly stored, manufactured, or packaged. The evidence we’ve reviewed does not show a consistent link between price and oxidation levels across different brands or batches. This means that if you’re looking for a high-quality fish oil, checking the price alone won’t tell you whether it’s fresh or well-preserved. Instead, look for details like expiration dates, third-party testing reports, or statements about antioxidant additives like vitamin E, which help slow oxidation. Store your supplements in a cool, dark place, and consider buying smaller bottles to use them before they degrade.