Systematically Investigating the Qualities of Commercial Encapsulated and Industrial-Grade Bulk Fish Oils in the Chinese Market

Many fish oil supplements sold commercially do not contain the amount of EPA and DHA claimed on their labels, show signs of degraded fats beyond safe limits, and may contain harmful contaminants like heavy metals.

In a study of fish oil products in China, most commercial capsules met quality standards for oxidation, but nearly all bulk industrial samples did not, showing that bulk fish oil is more likely to be degraded.

In China, more expensive fish oil supplements are not consistently cleaner or safer than cheaper ones, as price does not reliably reflect how oxidized the oil is or whether it contains harmful metals.

In fish oil products sold in China, measurements of chemical oxidation do not reliably predict whether the oil smells fishy or rancid to consumers.

Testing of 25 fish oil supplements sold in China found that many did not contain the amount of EPA and DHA stated on their labels, which could affect their intended health benefits.

Testing of fish oil products in China found that unrefined bulk oils frequently contain unsafe levels of chromium and arsenic, while encapsulated products have lower but still notable contamination levels.