Best Fish Oil: How to Choose a Quality Omega-3

Fish oil is one of the most popular supplements, but quality varies widely and the front label can mislead. Choosing a good one comes down to a few specifics on the back of the bottle. Here is how.

Key takeaways

Judge fish oil by its EPA and DHA content, not the total fish oil number.
Look for third-party testing for purity and freshness.
Freshness matters, since rancid oil is unpleasant and lower quality.
Aim for a meaningful combined EPA and DHA dose per day.

Read the EPA and DHA, not the total

The big number on the front, often the total fish oil, is not what matters. Flip to the back and check the combined EPA and DHA content per serving, since those are the active omega-3s. Two products with the same total fish oil can deliver very different amounts of EPA and DHA.

Purity and freshness

Because fish can carry contaminants, third-party testing for heavy metals and other pollutants adds real value. Freshness matters too, as omega-3s oxidize over time and rancid oil is both unpleasant and lower quality. Look for products that test for freshness, and store them properly, some in the fridge.

Meaningful combined EPA and DHA per serving
Third-party tested for contaminants
Tested or guaranteed for freshness
Reputable sourcing

Forms and dose

Fish oil comes in different forms, and both triglyceride and ethyl ester forms can work, though some people find the triglyceride form absorbs a little better. Aim for a daily combined EPA and DHA dose in line with general recommendations, and take it with a meal to aid absorption and reduce any fishy aftertaste.

Frequently asked questions

What should I look for in a fish oil?

A meaningful combined EPA and DHA dose, third-party testing for purity, and freshness. Ignore the total fish oil number on the front.

Why does freshness matter?

Omega-3s oxidize over time. Rancid oil is unpleasant and lower quality, so freshness testing and proper storage help.

Should I take fish oil with food?

Yes, taking it with a meal aids absorption and reduces any fishy aftertaste.

How we researched this. This guide is based on peer reviewed human research, systematic reviews, and established clinical guidance. We describe where evidence is strong, where it is mixed, and where it is still early, and we update the page as new studies are published.

This article is for general education and is not medical advice. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease and are not evaluated by the FDA for those uses. Talk with a qualified healthcare professional before starting anything new, especially if you are pregnant, nursing, taking medication, or managing a health condition.

References and Key Studies

How we researched this: Our editorial team reviewed peer-reviewed clinical research and independent health-authority guidance before writing and reviewing this article. Key studies are listed below so you can read the science yourself.

Nicholls SJ, et al. (2020). Effect of High-Dose Omega-3 Fatty Acids vs Corn Oil on Major Adverse Cardiovascular Events in Patients at High Cardiovascular Risk: The STRENGTH Randomized Clinical Trial. JAMA. PubMed: 33190147
Abdelhamid AS, et al. (2020). Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev. PubMed: 32114706
Abdelhamid AS, et al. (2018). Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev. PubMed: 30019766

Further reading: NIH Office of Dietary Supplements fact sheet · More research on omega-3 fatty acids (PubMed) · Google Scholar