Does fish oil help with depression and anxiety?

For people who already have major depression, omega-3 from fish oil eases symptoms a little, and probably not by enough to feel. A 2021 Cochrane review pooled 33 placebo-controlled trials in 1848 adults and found a standardized mean difference of -0.40, on evidence it rated very low certainty. The authors put that at about 2.5 points on the Hamilton depression scale, where the smallest change patients notice is 3 points. For preventing depression in people who are well, the answer is no.

Unsettled. Omega-3 for major depression is a small effect on weak evidence. The trials are small, their results differ widely, and the Cochrane authors found signs that bias pushes the pooled number upward. Remission and response rates were no better than on placebo.

Points on the 17-item Hamilton depression scale

The first bar is the Cochrane authors' own translation of their pooled result, with its 95 percent interval. The second is the smallest change on this scale that patients register as real. The interval runs across it, so the true effect could be noticeable or negligible. Source: card ev-fodep-02 below.

What the trials found

Treating depression

The Cochrane result has a confidence interval running from -0.64 to -0.16, so the benefit could be modest or almost nothing. The things a patient would count as getting better did not move. In 8 trials with 609 people, remission was no different on omega-3 than on placebo (odds ratio 1.13, 0.74 to 1.72). Response in 17 trials with 794 people was no different either (odds ratio 1.20, 0.80 to 1.79). Both were rated low certainty.

The type of oil may matter. A 2019 meta-analysis of double-blind trials split the formulas by what they contained. Products that were pure EPA, or at least 60 percent EPA, showed a benefit when the EPA dose was up to 1 g a day, with standardized differences of -0.50 and -1.03. Products built mainly on DHA showed none. That is a subgroup finding, and the abstract reports P values without confidence intervals.

In older adults with depression, a 2025 meta-analysis of anti-inflammatory treatments found a small benefit for omega-3, a standardized difference of -0.14 (95% CI -0.27 to -0.02). In children and teenagers, a 2024 Cochrane review of 5 small trials in 185 young people found a difference of -0.34 with an interval from -0.85 to 0.17 that crosses zero, and called the evidence very uncertain.

Preventing depression

Myth. Fish oil does not keep depression away in people who do not have it. A meta-analysis of 31 trials with 41,470 people, at a median 0.95 g a day for 12 months, found a risk ratio of 1.01 (0.92 to 1.10) for depression symptoms, on moderate-quality evidence.

The largest single trial pointed the wrong way. VITAL-DEP gave 18,353 US adults aged 50 or older either 1 g of fish oil a day or placebo for 5.3 years. Depression came on in 13.9 per 1000 person-years on fish oil and 12.3 on placebo, a hazard ratio of 1.13 (1.01 to 1.26). That is a small, borderline excess in a general older population. It is not evidence that fish oil worsens depression that is already there.

Cases of depression per 1000 person-years

Raw event rates from the largest prevention trial, 18,353 people who were not depressed at the start. The hazard ratio was 1.13 (95% CI 1.01 to 1.26). Rates, so no intervals are drawn on the bars. Source: card ev-fodep-06 below.

Pregnancy and after birth

A meta-analysis of 18 trials with 4052 women found no effect on depressive symptoms during pregnancy, with a standardized difference of -0.071. After birth the estimate was -0.656 with an interval from -1.690 to 0.378, too imprecise to call a benefit. The authors advise against prescribing omega-3 to treat or prevent depressive symptoms during pregnancy.

Anxiety

A 2024 dose-response meta-analysis of 23 trials in 2189 adults found the largest improvement in anxiety at 2 g a day (standardized difference -0.93, 95% CI -1.85 to -0.01), and no effect below 2 g. The authors rated the certainty of their main dose estimate low, and the 2 g interval nearly reaches zero. The prevention meta-analysis above, at a median 1.1 g a day, found little or no effect on anxiety symptoms, on moderate-quality evidence.

Omega-3 against placebo, as odds, risk or hazard ratios

Treating depressionPreventing depressionPossible harms

Above 1 means more of the outcome. For remission and response more is better, for every other row more is worse. The atrial fibrillation row applies only to high doses in people at high cardiovascular risk, where the absolute difference was 0.8 percent. Sources: cards ev-fodep-03, 05, 06, 08, 09 and 10 below.

Who should be careful

In the depression trials, the number of people reporting side effects was similar on omega-3 and placebo (odds ratio 1.27, 0.99 to 1.64, 24 trials, 1503 people). The Cochrane authors say that range still allows a modest increase, and the certainty is very low. At 1 g a day for 5.3 years in VITAL-DEP, gastrointestinal bleeding was 2.6 percent on fish oil against 2.7 on placebo, and stomach upset 35.2 against 35.1.

Not for everyone. Two cautions matter at the higher doses some depression trials use. Across 11 trials with 120,643 patients, omega-3 did not raise bleeding overall (rate ratio 1.09, 0.91 to 1.31). High-dose purified EPA raised the relative risk of bleeding by 50 percent, which was 0.6 percent in absolute terms. And in people at high cardiovascular risk taking more than 1.5 g of EPA plus DHA a day, atrial fibrillation rose (odds ratio 1.43, 1.14 to 1.79), an absolute difference of 0.8 percent. If you have heart disease, a high dose is a question for your doctor.

Fish oil is not a replacement for treatment. Both bodies below place it next to an antidepressant rather than in place of one.

What expert bodies say

The World Federation of Societies of Biological Psychiatry and the Canadian Network for Mood and Anxiety Treatments reviewed nutraceuticals for depression in 2022. They recommend omega-3 as an add-on to antidepressants in unipolar depression, and do not currently recommend it as a stand-alone treatment.

The US National Center for Complementary and Integrative Health says it is uncertain whether omega-3 supplements help depression. It notes reviews suggesting that EPA may do more than DHA, and that omega-3 may work best alongside antidepressant medication.

How we searched

Searched: a local copy of the PubMed baseline, on 7 October 2026, for fish oil, omega-3, EPA, DHA or n-3 fatty acids with depression, depressive symptoms or anxiety. The broad query returned 649 records and we reviewed the top 40. Narrower queries on Cochrane reviews, prevention and the VITAL trial returned 99 syntheses, guidelines and trials, and a query on bleeding and atrial fibrillation returned 126. We also checked the NIH supplement fact sheets, a drug interaction layer, the EU claims register, ClinicalTrials.gov and Retraction Watch. None of the papers used has been retracted. One web search for 2025 meta-analyses and the NCCIH fact sheet, read twice, completed the pass.

Included: two Cochrane reviews, seven other meta-analyses, the VITAL-DEP trial, the 2022 WFSBP and CANMAT guideline and the NCCIH fact sheet.

Excluded: a smaller perinatal meta-analysis that overlaps the one used, an umbrella review and a narrative review without pooled numbers, a 2025 meta-analysis that mixes randomized and observational studies, and two network meta-analyses of broader treatments.

What we read: abstracts from the PubMed baseline, with every quotation checked against the abstract text, and the NCCIH page itself.

What we could not get: the full text of the 2021 Cochrane review, which would give the doses and formulas of each trial. The NIH omega-3 fact sheet is not in our local layer, and we did not find a specific fish oil recommendation from the American Psychiatric Association or NICE.

What would change this answer

Large, adequately powered trials of EPA-rich omega-3 added to antidepressants in major depression. The EPA signal comes from subgroups of small trials, and one well-run trial would test it.
Trials that recruit people with major depression and high markers of inflammation. Our search log names this group as the one where a new trial would be most informative.
For prevention, VITAL-DEP has largely closed the question for adults over 50. A new trial would need a different population to reopen it.

More on fish oil: fish oil and inflammation, fish oil and triglycerides and fish oil and pregnancy.

The food behind this question

Fish oil: lower triglycerides, no fewer deaths — numbers, evidence and safety

The same question for other foods (depression)

Does saffron help with depression?

Sources

ev-fodep-01 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 1848
For the placebo comparison, n-3PUFA supplementation resulted in a small to modest benefit for depressive symptomology, compared to placebo: standardised mean difference (SMD) (random-effects model) -0.40 (95% confidence interval (CI) -0.64 to -0.16; 33 studies, 1848 participants; very low-certainty evidence), but this effect is unlikely to be clinically meaningful.
Who: adults with major depressive disorder in randomized trials of n-3 PUFA vs placebo
Effect: SMD -0.40 (95% CI -0.64 to -0.16), 33 studies, very low-certainty evidence
Certainty: GRADE very low; considerable heterogeneity; sensitivity analyses suggest bias toward a positive result.
Cochrane Database Syst Rev, 2021 · checked 2026-10-07 · we read the abstract
ev-fodep-02 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 1848
An SMD of 0.40 represents a difference between groups in scores on the HDRS (17-item) of approximately 2.5 points (95% CI 1.0 to 4.0), where the minimal clinically important change score on this scale is 3.0 points.
Who: adults with major depressive disorder in randomized trials of n-3 PUFA vs placebo
Effect: about 2.5 HDRS-17 points (95% CI 1.0 to 4.0); minimal clinically important change 3.0 points
Certainty: Interval spans both a meaningful and a negligible effect; remission and response not different from placebo.
Cochrane Database Syst Rev, 2021 · checked 2026-10-07 · we read the abstract
ev-fodep-03 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 609
There was no evidence for a difference between n-3PUFA and placebo groups in remission rates (OR 1.13, 95% CI 0.74 to 1.72; 8 studies, 609 participants, low-certainty evidence), response rates (OR 1.20, 95% CI 0.80 to 1.79; 17 studies, 794 participants; low-certainty evidence), quality of life (SMD -0.38 (95% CI -0.82 to 0.06), 12 studies, 476 participants, very low-certainty evidence), or trial non-completion (OR 0.92, 95% CI 0.70 to 1.22; 29 studies, 1777 participants, very low-certainty evidence).
Who: adults with major depressive disorder
Effect: remission OR 1.13 (95% CI 0.74 to 1.72), 8 studies, low certainty; response OR 1.20 (0.80 to 1.79), 17 studies, 794 participants
Certainty: Low certainty; small trials.
Cochrane Database Syst Rev, 2021 · checked 2026-10-07 · we read the abstract
ev-fodep-04 · Meta-analysis or systematic review · meta-analysis of double-blind randomized placebo-controlled trials · n = 2160
Compared with placebo, EPA-pure (=100% EPA) and EPA-major formulations (≥60% EPA) demonstrated clinical benefits with an EPA dosage ≤1 g/d (SMD = -0.50, P = 0.003, and SMD = -1.03, P = 0.03, respectively), whereas DHA-pure and DHA-major formulations did not exhibit such benefits.
Who: participants in double-blind placebo-controlled trials of omega-3 for depression
Effect: overall SMD -0.28; EPA-pure SMD -0.50; EPA-major (60% EPA or more) SMD -1.03 at EPA up to 1 g/d; DHA-pure and DHA-major no benefit
Certainty: Subgroup finding; confidence intervals not reported in abstract (P values only).
Transl Psychiatry, 2019 · checked 2026-10-07 · we read the abstract
ev-fodep-05 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials with GRADE · n = 41470
Meta-analysis suggested that increasing long-chain omega-3 probably has little or no effect on risk of depression symptoms (risk ratio 1.01, 95% CI 0.92-1.10, I2 = 0%, median dose 0.95 g/d, duration 12 months) or anxiety symptoms (standardised mean difference 0.15, 95% CI 0.05-0.26, I2 = 0%, median dose 1.1 g/d, duration 6 months; both moderate-quality evidence).
Who: adults with or without depression or anxiety randomized to more long-chain omega-3 for 24 weeks or longer
Effect: depression symptoms RR 1.01 (95% CI 0.92 to 1.10), median 0.95 g/d for 12 months; anxiety SMD 0.15 (0.05 to 0.26); moderate-quality evidence
Certainty: Moderate quality; results did not differ by dose or duration.
Br J Psychiatry, 2021 · checked 2026-10-07 · we read the abstract
ev-fodep-06 · Randomized controlled trial(s) · randomized double-blind placebo-controlled 2x2 factorial trial · n = 18353
Depression risk was significantly higher comparing omega-3 (651 events, 13.9 per 1000 person-years) with placebo (583 events, 12.3 per 1000 person-years; hazard ratio [HR], 1.13; 95% CI, 1.01-1.26; P = .03).
Who: US adults aged 50 or older without clinically relevant depressive symptoms at baseline; 1 g/d fish oil (465 mg EPA, 375 mg DHA) vs placebo
Effect: 13.9 vs 12.3 events per 1000 person-years; HR 1.13 (95% CI 1.01 to 1.26); PHQ-8 mood score difference 0.03 (-0.01 to 0.07)
Certainty: Prevention in a general older population, not treatment of depression; small excess, borderline significance.
JAMA, 2021 · checked 2026-10-07 · we read the abstract
ev-fodep-07 · Randomized controlled trial(s) · randomized double-blind placebo-controlled 2x2 factorial trial · n = 18353
Regarding serious and common adverse events, the respective prevalence values in omega-3 vs placebo groups were major cardiovascular events (2.7% vs 2.9%), all-cause mortality (3.3% vs 3.1%), suicide (0.02% vs 0.01%), gastrointestinal bleeding (2.6% vs 2.7%), easy bruising (24.8% vs 25.1%), and stomach upset or pain (35.2% vs 35.1%).
Who: US adults aged 50 or older; 1 g/d fish oil vs placebo
Effect: GI bleeding 2.6% vs 2.7%; easy bruising 24.8% vs 25.1%; stomach upset 35.2% vs 35.1%; suicide 0.02% vs 0.01%
Certainty: Dose 1 g/d; depression trials often use 1 to 4 g/d.
JAMA, 2021 · checked 2026-10-07 · we read the abstract
ev-fodep-08 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 1503
Although the numbers of individuals experiencing adverse events were similar in intervention and placebo groups (odds ratio (OR) 1.27, 95% CI 0.99 to 1.64; 24 studies, 1503 participants; very low-certainty evidence), the confidence intervals include a small decrease to a modest increase in adverse events with n-3PUFAs.
Who: adults with major depressive disorder
Effect: adverse events OR 1.27 (95% CI 0.99 to 1.64), 24 studies, very low certainty
Certainty: Very low certainty; adverse events poorly reported.
Cochrane Database Syst Rev, 2021 · checked 2026-10-07 · we read the abstract
ev-fodep-09 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized clinical trials · n = 120643
A prespecified analysis was performed in patients receiving high-dose purified eicosapentaenoic acid (EPA), which demonstrated a 50% increase in the relative risk of bleeding but only a modest increase in the absolute risk of bleeding (0.6%) when compared with placebo.
Who: patients in randomized trials of omega-3 PUFA, mostly cardiovascular
Effect: bleeding rate ratio 1.09 (95% CI 0.91 to 1.31); high-dose purified EPA about 50% relative and 0.6% absolute increase
Certainty: Cardiovascular trial populations; bleeding linked to EPA dose, not to antiplatelet use.
J Am Heart Assoc, 2024 · checked 2026-10-07 · we read the abstract
ev-fodep-10 · Meta-analysis or systematic review · meta-analysis of randomized controlled trials · n = 114592
Only studies including patients at high-risk for cardiovascular disease who were treated with high-doses of EPA/DHA (>1500 mg/d) showed a statistically significant increase in AF risk with a pooled odds ratio (OR) of 1.43 (95% CI, 1.14-1.79) and an absolute risk difference of 0.8% (0.40%-1.1%).
Who: adults 50 or older in randomized trials of at least 500 mg/d EPA plus DHA for 12 months or more
Effect: high risk, high dose OR 1.43 (95% CI 1.14 to 1.79), absolute difference 0.8%; other groups OR 1.03 to 1.07, not significant
Certainty: Relevant to depression doses of 1 to 4 g/d in older patients with heart disease.
Circ Arrhythm Electrophysiol, 2026 · checked 2026-10-07 · we read the abstract
ev-fodep-11 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 185
Omega-3 PUFA supplementation compared to placebo may reduce self-reported depression symptoms, but the evidence is very uncertain (standardized mean difference [SMD] -0.34, 95% confidence interval [CI] -0.85 to 0.17; lower SMD means greater improvement in depression due to omega-3 PUFA; 5 trials, 185 participants; very low-certainty evidence).
Who: children and adolescents aged 19 or younger with diagnosed depression; 10 to 16 weeks of omega-3 vs placebo
Effect: SMD -0.34 (95% CI -0.85 to 0.17), 5 trials, very low certainty; remission OR 1.11 (0.45 to 2.75)
Certainty: Interval crosses no effect; no serious adverse effects reported.
Cochrane Database Syst Rev, 2024 · checked 2026-10-07 · we read the abstract
ev-fodep-12 · Meta-analysis or systematic review · meta-analysis of randomized controlled trials · n = 4052
We advise against prescribing omega-3 PUFAs for the treatment or prevention of depressive symptoms during pregnancy, given a lack of effect with low heterogeneity.
Who: pregnant and postpartum women in randomized trials of omega-3 PUFA for prevention or treatment of perinatal depression
Effect: overall SDM -0.236 (95% CI -0.463 to -0.009); pregnancy SDM -0.071; postpartum SDM -0.656 (-1.690 to 0.378)
Certainty: Heterogeneity I2 89%; postpartum estimate imprecise.
J Clin Psychiatry, 2020 · checked 2026-10-07 · we read the abstract
ev-fodep-13 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials · n = 31 RCTs
Sub-group analyses supported the use of omega-3 fatty acids (SMD = -0.14, 95% CI = -0.27 to -0.02, p = 0.03) and botanical drug or dietary intervention (SMD = -0.86, 95% CI = -1.58 to -0.13, p = 0.02) among older participants.
Who: older adults in randomized trials of anti-inflammatory interventions for depression
Effect: omega-3 subgroup SMD -0.14 (95% CI -0.27 to -0.02)
Certainty: Substantial heterogeneity; small effect.
Transl Psychiatry, 2025 · checked 2026-10-07 · we read the abstract
ev-fodep-14 · Meta-analysis or systematic review · systematic review and dose-response meta-analysis of randomized controlled trials · n = 2189
The non-linear dose-response analysis indicated the greatest improvement at 2 g/d (SMD: -0.93, 95%CI: -1.85, -0.01), and that supplementation in a dose lower than 2 g/d did not affect anxiety symptoms.
Who: adults in randomized trials of omega-3 supplementation measuring anxiety symptoms
Effect: per 1 g/d SMD -0.70 (95% CI -1.17 to -0.22), low GRADE; at 2 g/d SMD -0.93 (-1.85 to -0.01); below 2 g/d no effect
Certainty: GRADE low for the linear per-1 g estimate (abstract); 2 g/d interval nearly reaches zero; contrasts with prevention MA (ev-fodep-05) showing no anxiety benefit at about 1 g/d.
BMC Psychiatry, 2024 · checked 2026-10-07 · we read the abstract
ev-fodep-15 · Position of an expert body · international clinical guideline based on meta-reviews of meta-analyses and RCTs · n = —
RESULTS: Amongst nutraceuticals with Grade A evidence, positive directionality and varying levels of support (recommended, provisionally recommended, or weakly recommended) was found for adjunctive omega-3 fatty acids (+++), vitamin D (+), adjunctive probiotics (++), adjunctive zinc (++), methylfolate (+), and adjunctive s-adenosyl methionine (SAMe) (+) in the treatment of unipolar depression.
Who: adults with unipolar depression
Effect: adjunctive omega-3 recommended (+++); monotherapy omega-3 not currently recommended (+/-); weak support for bipolar depression (+)
Certainty: Professional-society guideline; graded on Grade A evidence (meta-analyses or 2 or more RCTs).
World J Biol Psychiatry, 2022 · checked 2026-10-07 · we read the abstract
ev-fodep-16 · Position of an expert body · agency consumer fact sheet · n = —
Although some studies have had promising results, it's uncertain whether omega-3 fatty acid supplements are helpful for depression.
Who: people with depression
Effect: uncertain benefit
Certainty: Consumer summary citing the 2021 Cochrane review (ev-fodep-01).
NIH National Center for Complementary and Integrative Health, Omega-3 Supplements: What You Need To Know, last updated November 2024 · checked 2026-10-07 · we read the section
ev-fodep-17 · Position of an expert body · agency consumer fact sheet · n = —
Other reviews have suggested that if omega-3s do have an effect, EPA may be more beneficial than DHA and that omega-3s may best be used in addition to antidepressant medication rather than in place of it.
Who: people with depression
Effect: EPA over DHA; adjunct rather than replacement
Certainty: T2 summary; effect sizes from ev-fodep-04 and ev-fodep-15.
NIH National Center for Complementary and Integrative Health, Omega-3 Supplements: What You Need To Know, last updated November 2024 · checked 2026-10-07 · we read the section

How this page was made. Evidence was extracted from primary sources into cards, every number was re-checked against the source, and the text was written from those cards. Bioma Learn has no human medical reviewer at this time, and we say so rather than invent one. Methodology. This is information, not medical advice.