fatty acid · for low mood
Omega-3
EPA calms inflammation in the brain and appears to make serotonin signalling work better.
Say that in clinical terms
EPA reduces neuroinflammation via resolvin and protectin synthesis, enhances serotonin receptor sensitivity, and modulates HPA axis function. Low omega-3 status is consistently associated with depression in epidemiological studies.
How strong is the research?
A Cochrane review of 35 trials in about 1,964 adults found only a small improvement — too small to be sure it matters.
2 papers read, 1 supporting, 1 against.
Tested as: EPA-dominant omega-3 supplement (≥60% EPA by weight, ≤1 g/day total dose)
Who was studied: People with diagnosed major depression, not healthy adults feeling flat.
How much to take
daily with meals
1000–2000 mg
EPA-predominant formulas (at least 60% EPA) show strongest antidepressant effects. Allow 8-12 weeks for mood improvement.
Before you take it
- FDA GRAS limit for dietary supplements: up to 5 g/day of combined EPA+DHA (not 3 g/day; the lower figure reflects an older FDA enforcement discretion letter, not the current GRAS determination).
- No formal Tolerable Upper Intake Level (UL) has been established by the IOM/NAM for EPA or DHA.
- Doses of 2–15 g/day may increase bleeding time by reducing platelet aggregation; clinically relevant when combined with anticoagulants (warfarin), antiplatelet agents (aspirin, clopidogrel), or NSAIDs.
- INR monitoring is advisable when omega-3 supplements are added to warfarin therapy; most evidence suggests doses of 3–6 g/day do not significantly alter anticoagulant status, but individual variation exists.
- Extended use at 4 g/day in individuals with established CVD or at high CVD risk is associated with a modestly increased risk of atrial fibrillation (documented in STRENGTH and REDUCE-IT trials).
- High doses (≥900 mg EPA plus 600 mg DHA/day) may reduce immune function.
- Omega-3 may add to the blood-pressure-lowering effect of antihypertensive medications; blood pressure monitoring is advisable when initiating supplementation in patients already on antihypertensive therapy.
- Common side effects include fishy aftertaste, belching, gastrointestinal discomfort, and nausea; these are dose-dependent and usually mild.
- Individuals with fish or shellfish allergies should verify product sourcing; algal EPA/DHA is a fish-free alternative.
- Oxidized (rancid) fish oil may have pro-inflammatory effects; product freshness and storage conditions matter.
- At doses ≥2 g/day, potential additive bleeding risk when combined with antidepressants (SSRIs or SNRIs) that have antiplatelet properties — patients should discuss with their prescribing clinician before adding omega-3 to antidepressant therapy.
When to take it
Best taken: with food
What we make of it
Cochrane rated the evidence "very uncertain" and flagged possible publication bias.
The detail
The research is real, but the Cochrane review rated it very uncertain because trials disagree with each other so much, and noted signs that studies finding nothing may not have been published.