Omega-3 Supplements: EPA, DHA and Choosing a Source

Omega-3 supplements are compared on one figure that most front labels do not show: the combined EPA and DHA per capsule. Total oil weight — the number printed largest — is the wrong thing to shop on.

The number that matters

A softgel described as 1,000 mg of fish oil might carry 300 mg of EPA and DHA, or considerably more. The omega-3 content is on the back panel, broken out by fatty acid. Two products with identical front labels can differ by a factor of two or three on the figure that describes what you are actually taking. See EPA and DHA explained.

Sources

Fish oil is the standard. Krill oil delivers omega-3 in phospholipid form, typically at lower doses per capsule, and states astaxanthin content. Algal oil is the option for anyone avoiding marine animal sources and is usually DHA-dominant where fish oil is more often EPA-dominant. Cod liver oil additionally carries vitamin A and vitamin D, so its panel has three figures to read. See krill oil vs fish oil.

Concentration and form

Triglyceride and ethyl ester forms are both widely sold and named on the panel. Concentrated products fit more EPA and DHA into fewer capsules, which changes serving burden as well as cost per gram of omega-3.

Purity, freshness and storage

Heavy metal and oxidation testing are the two quality questions specific to this category. Where a manufacturer states a purity standard or an oxidation limit, we record it. Fish oil oxidises, and a strongly rancid smell is a reason to return a product rather than finish it.

Safety

High doses of omega-3 can affect bleeding time and interact with anticoagulant medication. If you take blood thinners, are scheduled for surgery, or have a fish or shellfish allergy, speak to your doctor or pharmacist before starting.

Comparing products

Our omega-3 comparison filters by brand, strength, format and pack size, alongside fish oil and krill oil.

References

• NIH Office of Dietary Supplements — Omega-3 Fatty Acids (Health Professional Fact Sheet)
• NCCIH — Omega-3 Supplements: In Depth