Full profile
| Also known as | Fish oil, Algal oil, EPA, DHA, Long-chain omega-3 PUFA |
|---|---|
| Best for | Foundational brain-nutrition layer · Filling a common dietary gap (low fish intake) · Long-term maintenance rather than acute focus |
| Evidence grade | Grade C — Limited — early or small human trials |
| Studied dose range | 250–500 mg combined EPA+DHA daily as a general baseline; Health Canada's cognitive-support window is 150–5,000 mg EPA+DHA with ≥100 mg DHA/day. |
| Time to effect | Not acute; a structural-nutrition play measured over months, if at all, in healthy adults. |
| Best form | Triglyceride-form fish oil, or algal (Schizochytrium) oil for a vegan DHA source. Look for stated EPA/DHA milligrams, not just total 'fish oil' weight. |
| Food sources | Salmon, Sardines, Mackerel, Anchovies, Algae (DHA) |
Evidence, honestly graded
For its own roles (cardiovascular, triglycerides) the evidence is strong, but for cognition in already-healthy adults it is weak: a Cochrane review (Sydenham 2012) found no cognitive benefit in cognitively healthy older adults, and the AREDS2 RCT (Chew 2015) found no significant cognitive effect. Graded C for the healthy-adult cognition angle, positioned honestly as a foundational nutrient rather than an enhancer.
See the full grading rubric — study type, replication, population match, and dose adequacy — in The Evidence Standard.
Side effects
- Fishy aftertaste or burps
- Mild GI upset
- Loose stools at higher doses
Who should avoid it or check first
- Fish or shellfish allergy (use algal oil)
- On anticoagulants without clinician review
- Pregnant or breastfeeding without clinician guidance on dose and source
Interactions
- May add to the effect of anticoagulant or antiplatelet medication
- Very high doses may affect bleeding time — discuss with a clinician
Stacks well with
- Vitamin D3
- B-Complex (B6, B9, B12)
- Phosphatidylserine
Use caution stacking with
- Redundant to combine multiple high-dose fish/algal oils without rationale
What to look for on a label
- State EPA and DHA in milligrams per serving separately — 'fish oil 1000 mg' is not the same as EPA+DHA content.
- Health Canada's Fish Oil monograph permits a 'helps support cognitive health/brain function' claim at 150–5,000 mg EPA+DHA (incl. ≥100 mg DHA/day); do not imply prevention of cognitive decline or dementia, which trials do not support and which exceeds the permitted claim.
References
- Sydenham 2012, Cochrane Database Syst Rev. No cognitive benefit from omega-3 in cognitively healthy older adults. PMID 22696350; doi:10.1002/14651858.CD005379.pub3. Educational, not a product claim.
- Chew 2015, JAMA — AREDS2 cognition RCT. No significant cognitive effect of omega-3 supplementation. PMID 26305649; doi:10.1001/jama.2015.9677. Anchors honest framing.
- Health Canada NNHPD Fish Oil monograph. Permits a cognitive/brain-function support claim within a defined EPA+DHA dose window. webprod.hc-sc.gc.ca/nhpid-bdipsn (verify current claim text before filing).
Primary citations for some entries above are still being compiled; those without a linked identifier are editorial summaries of the wider literature.
Grades and studied doses are our conservative reading of the human research, shown for education. They are not product claims, and a studied dose is not a recommended dose.
See how Omega-3 (EPA/DHA) compares on grade, dose, and goal in the Evidence Explorer.