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Also known as Fish Oil, Krill Oil, EPA, DHA
Long-chain polyunsaturated fatty acids from fish or algal oil that are incorporated into cell membranes and reduce pro-inflammatory eicosanoid production; linked to cardiovascular, joint, and neurological benefits.
We link to relevant studies and leave interpretation to you and your healthcare professional.
Number of audited published findings for Omega-3 (EPA/DHA) by condition. Drill into a pair page for the full breakdown.
Where people report using it and what trials suggest
Common claims the trials do not support
EPA/DHA from fish or algae. Strong for severe hypertriglyceridaemia (high-dose EPA), otherwise cardiovascular results in large trials are inconsistent.
Safety notes: Bleeding risk at very high doses is contested; AFib signal at ≥1g/day in cardiac patients warrants medical advice.
Evidence grades reflect study quality and consistency, not marketing claims.
Summaries of published trial results for this compound, grouped by condition. Numbers are reported exactly as the researchers published them — we never calculate or convert.
How to read this table
In short: benefit is what was observed; evidence is how much you should trust the observation. A “Benefit seen” tag on a weak study counts for far less than the same tag on a meta-analysis.
| Outcome measured | What trials found | Effect size | People studied | Duration | Type of evidence | Study |
|---|---|---|---|---|---|---|
| depression symptoms | Depression symptoms improved with an SMD of -0.28 vs placebo in 2160 participants. (P=0.004)Benefit seen | -0.28 SMD | 2160 | — | Meta-analysis · 2019 | PMID 31383846 |
| depression symptoms (DHA-pure and DHA-major) | No benefit was found for DHA-pure and DHA-major formulations compared to placebo.No clear benefit | no number reported | — | — | Meta-analysis · 2019 | PMID 31383846 |
| depression symptoms (EPA-major) | Depression symptoms improved with an SMD of -1.03 vs placebo for EPA-major formulations. |
Associated conditions and community-reported outcomes, wrapped together on one page. Aggregates appear only once enough reports arrive.
How this compound is sold in the UK, and where our readers typically find it.
Retailer search links — we may earn commission on purchases at no cost to you. Commission never affects our evidence ratings.
| -1.03 SMD |
| — |
| — |
| Meta-analysis · 2019 |
| PMID 31383846 |
| depression symptoms (EPA-pure) | Depression symptoms improved with an SMD of -0.50 vs placebo for EPA-pure formulations. (P=0.003)Benefit seen | -0.50 SMD | — | — | Meta-analysis · 2019 | PMID 31383846 |
| adverse events | No difference in adverse events vs placebo (OR 1.27) in 1503 participants. (95% CI 0.99 to 1.64)No clear benefit | 1.27 OR | 1503 | — | Systematic review · 2021 | PMID 34817851 |
| depressive symptomology (continuous) | Small benefit of 0.40 SMD vs placebo in 1848 people, but unlikely clinically meaningful. (95% CI -0.64 to -0.16)No clear benefit | -0.40 SMD | 1848 | — | Systematic review · 2021 | PMID 34817851 |
| depressive symptomology (vs antidepressants) | No difference in depressive symptomology vs antidepressants (MD -0.70) in 40 participants. (95% CI -5.88 to 4.48)No clear benefit | -0.70 MD | 40 | — | Systematic review · 2021 | PMID 34817851 |
| quality of life | No difference in quality of life vs placebo (SMD -0.38) in 476 participants. (95% CI -0.82 to 0.06)No clear benefit | -0.38 SMD | 476 | — | Systematic review · 2021 | PMID 34817851 |
| remission rates | No difference in remission rates vs placebo (OR 1.13) in 609 participants. (95% CI 0.74 to 1.72)No clear benefit | 1.13 OR | 609 | — | Systematic review · 2021 | PMID 34817851 |
| response rates | No difference in response rates vs placebo (OR 1.20) in 794 participants. (95% CI 0.80 to 1.79)No clear benefit | 1.20 OR | 794 | — | Systematic review · 2021 | PMID 34817851 |
| response rates (vs antidepressants) | No difference in response rates vs antidepressants (OR 1.23) in 40 participants. (95% CI 0.35 to 4.31)No clear benefit | 1.23 OR | 40 | — | Systematic review · 2021 | PMID 34817851 |
| trial non-completion | No difference in trial non-completion vs placebo (OR 0.92) in 1777 participants. (95% CI 0.70 to 1.22)No clear benefit | 0.92 OR | 1777 | — | Systematic review · 2021 | PMID 34817851 |
| trial non-completion (vs antidepressants) | No difference in trial non-completion vs antidepressants (OR 1.00) in 40 participants. (95% CI 0.21 to 4.71)No clear benefit | 1.00 OR | 40 | — | Systematic review · 2021 | PMID 34817851 |
| Outcome measured | What trials found | Effect size | People studied | Duration | Type of evidence | Study |
|---|---|---|---|---|---|---|
| interleukin 6 (IL-6) | Omega-3 supplementation reduced IL-6 levels by an effect size of -0.22 compared to control in adults. (95% CI: -0.39, -0.05, p=0.010)Benefit seen | -0.22 | — | — | Meta-analysis · 2022 | PMID 35914448 |
| serum C-reactive protein (CRP) | Omega-3 supplementation reduced CRP levels by an effect size of -0.40 compared to control in adults. (95% CI: -0.56, -0.24, p<0.001)Benefit seen | -0.40 | — | — | Meta-analysis · 2022 | PMID 35914448 |
| Tumour necrosis factor α (TNFα) | Omega-3 supplementation reduced TNFα levels by an effect size of -0.23 compared to control in adults. (95% CI: -0.37, -0.08, p=0.002)Benefit seen | -0.23 | — | — | Meta-analysis · 2022 | PMID 35914448 |
| Outcome measured | What trials found | Effect size | People studied | Duration | Type of evidence | Study |
|---|---|---|---|---|---|---|
| Morning stiffness | Omega-3 did not significantly improve morning stiffness compared to placebo. (95% CI-0.955-0.212, p = 0.221)No clear benefit | -0.224 standardized mean difference | — | 3 months | Meta-analysis · 2012 | PMID 22835600 |
| NSAID consumption | Omega-3 reduced anti-inflammatory drug use compared to placebo, with a standardized mean difference of -0.518. (95% CI -0.915 to -0.121, p = 0.011)Benefit seen | -0.518 standardized mean difference | — | 3 months | Meta-analysis · 2012 | PMID 22835600 |
| Physical function | Omega-3 did not significantly improve physical function compared to placebo. (95% CI-0.232-0.724, p = 0.314)No clear benefit | 0.264 standardized mean difference | — | 3 months | Meta-analysis · 2012 | PMID 22835600 |
| Swollen joint count | Omega-3 did not significantly reduce swollen joint count compared to placebo. (95% CI-0.454-0.114, p = 0.241)No clear benefit | -0.170 standardized mean difference | — | 3 months | Meta-analysis · 2012 | PMID 22835600 |
| Tender joint count | Omega-3 did not significantly reduce tender joint count compared to placebo. (95% CI-0.489-0.062, p = 0.128)No clear benefit | -0.214 standardized mean difference | — | 3 months | Meta-analysis · 2012 | PMID 22835600 |