EPA and DHA from fish or algae. The “fish oil” number on the front is rarely the omega-3 number.
Omega-3s are a family of polyunsaturated fats. The three main ones are ALA (found in plant oils), and EPA and DHA (found mainly in fish, seafood and algae). Most omega-3 supplements are sold for their EPA and DHA content, sourced from fish oil, krill oil or algae oil.
The most important thing on an omega-3 label is the EPA + DHA amount per serving — not the total “fish oil” milligrams on the front. A 1,000 mg fish oil softgel may contain 300 mg or 700 mg of EPA + DHA depending on concentration.
Oil from fatty fish such as anchovies, sardines and mackerel. It provides both EPA and DHA; concentrated versions provide more per softgel.
Omega-3 oil from cultivated microalgae — a plant-based source of DHA and, in some products, EPA. Suitable for many vegetarians and vegans.
A long-chain omega-3 fatty acid found in fish and some algae. It’s listed separately from DHA on Supplement Facts panels.
A long-chain omega-3 fatty acid concentrated in the brain and retina. Algae oils are often DHA-dominant.
The clearest effect of EPA and DHA is lowering triglycerides at high doses. Evidence for broader heart, brain and eye outcomes from over-the-counter supplements is mixed. Fish oil and algae oil both provide EPA and DHA; algae oil has been shown to raise DHA levels comparably to fish in controlled research.
High doses of EPA and DHA lower triglyceride levels; prescription omega-3 medications are FDA-approved for very high triglycerides. Over-the-counter supplements are not the same as prescription products and are not a substitute for them.[1]
Large clinical trials of omega-3 supplements for preventing heart attacks and strokes have produced mixed results, varying with dose, formulation and the population studied.[1]
DHA is a structural component of the brain and retina. Studies of supplementation during pregnancy on infant outcomes have been mixed; pregnant people should discuss fish intake and supplements with their prenatal care provider.[1]
Some trials suggest omega-3 supplements may modestly help symptoms such as joint tenderness when used alongside standard treatment.[1]
Evidence labels summarize the overall body of published research for each topic; they are not a recommendation and do not mean a supplement is appropriate for you. Published research
Over-the-counter omega-3 supplements commonly provide roughly 250–1,000 mg of combined EPA + DHA per serving, with “concentrated” or “triple strength” products at the upper end. No Tolerable Upper Intake Level has been established; high intakes can affect bleeding, so larger amounts should be discussed with a clinician.
[1]These describe what supplements commonly contain and published reference values — not a recommendation for you.
Source[1]
Not a complete list. Ask a pharmacist or clinician about your specific medications.
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Source, EPA/DHA labels, dietary preferences and value.
Compare →Total oil vs EPA + DHA, oil forms, source and cost per 1,000 mg.
The two formulas SuppScout uses, with worked examples for creatine, magnesium and omega-3.
Dose, formulation and population explain much of the disagreement between large trials.
It depends entirely on concentration. Standard fish oil is often around 30% EPA + DHA (about 300 mg per 1,000 mg), while concentrated oils can be 60% or more. The Supplement Facts panel lists EPA and DHA separately — add them together.
Algae oil is the original source of the DHA that accumulates in fish, and research has shown algal DHA raises blood DHA comparably to fish. Many algae products are DHA-heavy with less EPA, so compare the EPA and DHA lines. See fish oil vs algae.
Fish oil concentrates are usually sold as ethyl esters or as re-esterified triglycerides. Many labels don’t state the form; SuppScout shows “Not stated” when the label doesn’t say.
SuppScout links to primary and authoritative sources wherever possible. See our editorial policy for how sources are selected and how corrections are handled.
This page is educational and is not medical advice. Talk to a healthcare professional before starting a supplement, especially if you have a medical condition, take medications, or are pregnant or breastfeeding. Medical disclaimer.