Does fish oil help with inflammation and joint pain?

A little, if you have rheumatoid arthritis, and probably not if you have ordinary aches. In a 2017 meta-analysis of 42 trials, marine oil supplements reduced pain in rheumatoid arthritis by a small standardized amount (-0.21, 95% CI -0.42 to -0.004, 22 trials). In osteoarthritis the same review found no significant effect (-0.17, 95% CI -0.57 to 0.24, 5 trials), and the reviewers rated the evidence low quality overall. In VITAL, 19,611 middle-aged and older US adults taking 1 g a day for a median 5.3 years reported pain as often and as badly as those on placebo.

Established. Fish oil lowers blood markers of inflammation. An umbrella review of 32 meta-analyses found omega-3 supplements reduced CRP (effect size -0.40, 95% CI -0.56 to -0.24), TNF-alpha (-0.23) and IL-6 (-0.22). Heterogeneity was very high, and a lower marker is a blood test result. It does not show by itself that anyone feels better.

Reduction against placebo, standardized mean difference

A standardized mean difference puts trials that used different scales on one scale. Larger means a bigger drop. The 2017 osteoarthritis subgroup is not drawn because its interval crosses zero (-0.17, 95% CI -0.57 to 0.24). Sources: cards ev-foinf-01, ev-foinf-02, ev-foinf-04, ev-foinf-05 and ev-foinf-06 below.

What the trials found

Rheumatoid arthritis: small, consistent, and it may spare painkillers

Three meta-analyses agree on direction. A 2007 analysis of 17 trials in inflammatory joint pain found 3 to 4 months of omega-3 reduced patient-reported pain (-0.26), minutes of morning stiffness (-0.43), the number of tender joints (-0.29) and NSAID use (-0.40). Doctor-assessed pain did not change significantly. A meta-analysis of 10 trials in rheumatoid arthritis, with 370 patients taking at least 2.7 g a day for 3 months or more, found painkiller use fell (-0.518, 95% CI -0.915 to -0.121). A 2025 meta-analysis of 41 trials in 3,759 people with chronic pain found benefits in rheumatoid arthritis, migraine and mixed pain, and none in osteoarthritis. That 2025 review had very high heterogeneity.

Osteoarthritis: the reviews disagree

Unsettled. The answer for osteoarthritis splits along the reviews. The 2017 and 2025 meta-analyses found no significant benefit. A 2023 meta-analysis of 9 trials in 2,070 people with osteoarthritis found omega-3 eased pain slightly (-0.29, 95% CI -0.47 to -0.11). The 2023 estimate had moderate heterogeneity, and we found no analysis that explains why the reviews differ.

The longest trials lean negative. In a 2-year trial of 202 people with knee osteoarthritis, a high dose of fish oil giving 4.5 g of omega-3 a day was no better than a low dose of 0.45 g for pain or cartilage loss. The trial had no placebo group, so it compares two doses. In VITAL, 1,398 older adults with chronic knee pain took 1 g a day or placebo for about 5 years, and their knee pain did not differ at any point.

Everyday aches in healthy people

Myth. Taking fish oil for general aches and pains has been tested at scale, and it made no difference. In VITAL-Pain, 19,611 middle-aged and older US adults on 1 g a day for a median 5.3 years had an odds ratio of 0.99 (95% CI 0.94 to 1.04) for more frequent or more severe pain. Pain was measured once, at the end of the trial.

The large trials: no change in pain, more atrial fibrillation

Randomized trials

The pain row is an odds ratio for more frequent or more severe pain, so 1.0 means no difference. The atrial fibrillation rows come from trials run for heart disease, not arthritis. Sources: cards ev-foinf-08, ev-foinf-10 and fshoil-r6-05 below.

Who should be careful

Not for everyone. Fish oil supplements raise the risk of atrial fibrillation, an irregular heart rhythm. Across 7 large trials with 81,210 people, the hazard ratio was 1.25 (95% CI 1.07 to 1.46). A later analysis of 35 trials found the higher risk only in people at high cardiovascular risk taking more than 1,500 mg of EPA and DHA a day, with an odds ratio of 1.43 and an absolute rise of 0.8 percentage points. Those trials were run for heart disease, and the doses used in the rheumatoid arthritis trials, 2.7 g a day or more, are in that higher range. If you have a heart rhythm problem or high heart risk, talk to your doctor before a high dose.

At 1 g a day, the VITAL trial of 25,871 US adults over a median 5.3 years saw no excess bleeding or other serious adverse events. Higher doses were not tested there, and we found no trial of high-dose fish oil in people taking blood thinners, so this page cannot say whether that combination is safe. The NIH center for complementary health says side effects are usually mild: unpleasant taste, bad breath, bad-smelling sweat, headache, heartburn, nausea and diarrhea. For rheumatoid arthritis, the same center describes omega-3-rich foods as a possible addition to drug therapy, not a replacement for it.

What expert bodies say

The NIH center for complementary health cites a 2022 review of 30 studies with 1,420 participants and says omega-3-rich foods may improve pain and swollen and tender joints and might be an appropriate addition to drug therapy for rheumatoid arthritis. The EU did not authorize the label claim that omega-3 EPA and DHA help maintain healthy joints. That means the evidence did not meet the bar at assessment, which is weaker than proof of no effect. We could not reach the 2019 American College of Rheumatology guideline on osteoarthritis, so it is not cited here.

How we searched

Searched: a local copy of the PubMed baseline across all study types, with five queries combining fish oil, omega-3, EPA and DHA with rheumatoid arthritis, osteoarthritis, joint pain, knee pain, CRP, interleukin-6 and inflammation. The broadest returned several hundred records, most of them about dialysis, COVID-19, surgery or cancer. A narrower arthritis query showed about 60, with 12 meta-analyses. We also searched the EU health claims register and ran three web searches for the arthritis guideline, the NIH position and newer CRP meta-analyses. Search run on 7 October 2026.

Included: 13 sources on 14 cards: seven meta-analyses, four reports from randomized trials, the NIH omega-3 fact sheet and the EU claims register. One more card from our earlier fish oil work adds the newer atrial fibrillation analysis. None of the studies we checked is listed in the Retraction Watch database.

Excluded: CRP meta-analyses limited to dialysis, COVID-19, surgery, burns or cancer, a dose-response CRP analysis whose abstract gives no pooled effect size, a smaller osteoarthritis meta-analysis reported without a scale, a letter with no data, and a krill oil review.

What we read: abstracts from the PubMed baseline. The NIH fact sheet was checked by two independent requests.

What we could not get: the 2019 American College of Rheumatology and Arthritis Foundation guideline, which is outside our corpus and our list of trusted sites, the NIH Office of Dietary Supplements omega-3 fact sheet, which refused automated access, and the per-trial doses inside the pooled analyses.

What would change this answer

A large placebo-controlled trial in osteoarthritis at the doses used in rheumatoid arthritis. The reviews disagree, and the long trials either used 1 g a day or had no placebo.
A trial in rheumatoid arthritis that measures atrial fibrillation alongside pain, since the effective doses fall where the heart rhythm risk was seen.
Evidence that a lower CRP translates into less pain or less joint damage. The marker moves, and the link to symptoms is unproven.

The food behind this question

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

The same question for other foods (inflammation)

Sources

ev-foinf-01 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized trials with GRADE · n = 42 trials
A significant effect was found in patients with rheumatoid arthritis (22 trials; -0.21; 95% CI, -0.42 to -0.004) and other or mixed diagnoses (3 trials; -0.63; 95% CI, -1.20 to -0.06), but not in osteoarthritis patients (5 trials; -0.17; 95% CI, -0.57-0.24).
Who: patients with arthritis in randomized trials of oral marine oil supplements vs control; 30 trials with complete pain data
Effect: rheumatoid arthritis -0.21 (-0.42 to -0.004), 22 trials; osteoarthritis -0.17 (-0.57 to 0.24), 5 trials, not significant
Certainty: GRADE: low quality overall, moderate quality for rheumatoid arthritis; high heterogeneity (I2 63%).
Nutrients, 2017 · checked 2026-10-07 · we read the abstract
ev-foinf-02 · Meta-analysis or systematic review · systematic review and random-effects meta-analysis of RCTs · n = 2070
Pooled results showed that n-3 PUFAs supplementation could significantly relieve the arthritis pain as compared to placebo (standardized mean difference [SMD]: - 0.29, 95% confidence interval [CI] - 0.47 to - 0.11, p = 0.002, I2 = 60%).
Who: patients with osteoarthritis in RCTs of n-3 PUFA supplements vs placebo
Effect: pain SMD -0.29 (95% CI -0.47 to -0.11)
Certainty: Small standardized effect; moderate heterogeneity for pain (I2 60%); disagrees with earlier OA subgroup null results.
J Orthop Surg Res, 2023 · checked 2026-10-07 · we read the abstract
ev-foinf-03 · Meta-analysis or systematic review · systematic review and random-effects meta-analysis of RCTs · n = 3759
The benefits were significant for rheumatoid arthritis, migraine, and other mixed chronic pain conditions, but not for osteoarthritis or mastalgia.
Who: adults with chronic pain conditions in RCTs of omega-3 supplements, searched to February 2025
Effect: significant for rheumatoid arthritis, migraine, mixed pain; not for osteoarthritis or mastalgia
Certainty: Very high heterogeneity (I2 87%); RoB 2 assessed; trim-and-fill found minimal publication bias.
Front Med (Lausanne), 2025 · checked 2026-10-07 · we read the abstract
ev-foinf-04 · Meta-analysis or systematic review · meta-analysis of RCTs · n = 370
The analysis showed that omega-3 PUFAs clearly reduced nonsteroidal anti-inflammatory drug (NSAID) consumption (SMD -0.518, 95% CI -0.915 to -0.121, p = 0.011) without between-study heterogeneity (I(2) = 0%).
Who: 183 rheumatoid arthritis patients on omega-3 PUFAs (2.7 g/day or more, 3 months or more) and 187 placebo controls
Effect: NSAID consumption SMD -0.518 (95% CI -0.915 to -0.121), I2 0%
Certainty: Small trials; 2012 search.
Arch Med Res, 2012 · checked 2026-10-07 · we read the abstract
ev-foinf-05 · Meta-analysis or systematic review · meta-analysis of randomized controlled trials · n = 17 RCTs
Supplementation with omega-3 PUFAs for 3-4 months reduces patient reported joint pain intensity (SMD: -0.26; 95% CI: -0.49 to -0.03, p=0.03), minutes of morning stiffness (SMD: -0.43; 95% CI: -0.72 to -0.15, p=0.003), number of painful and/or tender joints (SMD: -0.29; 95% CI: -0.48 to -0.10, p=0.003), and NSAID consumption (SMD: -0.40; 95% CI: -0.72 to -0.08, p=0.01).
Who: patients with rheumatoid arthritis or joint pain from inflammatory bowel disease and dysmenorrhea
Effect: patient-assessed pain SMD -0.26 (95% CI -0.49 to -0.03); morning stiffness -0.43 (-0.72 to -0.15); painful/tender joints -0.29 (-0.48 to -0.10); NSAID use -0.40 (-0.72 to -0.08); physician-assessed pain not significant
Certainty: Older review; physician-assessed outcomes were null.
Pain, 2007 · checked 2026-10-07 · we read the abstract
ev-foinf-06 · Meta-analysis or systematic review · umbrella meta-analysis of meta-analyses · n = 32 meta-analyses
Our findings demonstrated that the n-3 PUFA supplementation significantly reduced serum C-reactive protein (CRP) (ES = -0.40; 95 % CI: -0.56, -0.24, p < 0.001; I2 = 89.5 %, p < 0.001), Tumour necrosis factor α (TNFα) (ES = -0.23; 95 % CI: -0.37, -0.08, p = 0.002; I2 = 60.1 %, p < 0.001), and interleukin 6 (IL-6) concentrations (ES = -0.22; 95 % CI: -0.39, -0.05, p = 0.010; I2 = 66.2 %, p < 0.001).
Who: adults with different health conditions in meta-analyses of n-3 PUFA supplementation
Effect: CRP ES -0.40 (95% CI -0.56 to -0.24); TNF-alpha -0.23 (-0.37 to -0.08); IL-6 -0.22 (-0.39 to -0.05)
Certainty: Very high heterogeneity for CRP (I2 89.5%); biomarker change, not symptoms; overlapping trials across meta-analyses.
Int Immunopharmacol, 2022 · checked 2026-10-07 · we read the abstract
ev-foinf-07 · Randomized controlled trial(s) · double-blind placebo-controlled 2x2 factorial RCT (subgroup) · n = 1398
WOMAC pain did not differ between the active vitamin D group and the vitamin D placebo group or between the active n-3 FA group and the n-3 FA placebo group at any time point during follow-up.
Who: VITAL participants with chronic knee pain at baseline, mean age 67.7, 66% women; 1 g/day marine n-3 FA or placebo
Effect: WOMAC pain did not differ at any time point; time-by-treatment P = 0.77; no effect on function or stiffness
Certainty: Large, long; dose 1 g/day is lower than in arthritis trials.
Arthritis Rheumatol, 2020 · checked 2026-10-07 · we read the abstract
ev-foinf-08 · Randomized controlled trial(s) · ancillary study of a double-blind placebo-controlled RCT · n = 19611
The ORs for higher pain prevalence or severity for vitamin D and omega-3 supplementation vs placebo were 0.99 ([CI] 0.94-1.05) and 0.99 ([CI] 0.94-1.04), respectively.
Who: middle-aged and older US adults in VITAL with complete end-of-trial pain data
Effect: OR for higher pain prevalence or severity 0.99 (95% CI 0.94 to 1.04)
Certainty: General population, not arthritis patients; pain measured once at trial end.
Pain, 2024 · checked 2026-10-07 · we read the abstract
ev-foinf-09 · Randomized controlled trial(s) · randomized double-blind multicentre trial · n = 202
In people with symptomatic knee OA, there was no additional benefit of a high-dose fish oil compared with low-dose fish oil.
Who: patients with knee osteoarthritis and regular knee pain; 15 mL/day high-dose fish oil (4.5 g n-3) vs low-dose blend (0.45 g n-3)
Effect: low-dose group had greater improvement in WOMAC pain and function at 2 years; no difference in cartilage volume loss
Certainty: No placebo arm; comparator oil may have its own effect.
Ann Rheum Dis, 2016 · checked 2026-10-07 · we read the abstract
ev-foinf-10 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs · n = 81210
In meta-analysis, the use of marine ɷ-3 fatty acid supplements was associated with an increased risk of AF (n=2905; HR, 1.25 [95% CI, 1.07-1.46]; P=0.013).
Who: participants in RCTs of cardiovascular outcomes with at least 500 people and 1 year follow-up; mean age 65
Effect: AF HR 1.25 (95% CI 1.07 to 1.46), 2,905 AF cases
Certainty: Trials in cardiovascular populations; arthritis doses (2.7 g/day or more) fall in the higher-risk range.
Circulation, 2021 · checked 2026-10-07 · we read the abstract
ev-foinf-11 · Randomized controlled trial(s) · randomized placebo-controlled 2x2 factorial trial · n = 25871
No excess risks of bleeding or other serious adverse events were observed.
Who: men 50 or older and women 55 or older in the US; 1 g/day marine n-3 fatty acids vs placebo
Effect: no excess risks of bleeding or other serious adverse events
Certainty: Dose 1 g/day; higher arthritis doses not tested here.
N Engl J Med, 2019 · checked 2026-10-07 · we read the abstract
ev-foinf-12 · Position of an expert body · agency consumer fact sheet · n = —
Side effects of omega-3 supplements are usually mild. They include unpleasant taste, bad breath, bad-smelling sweat, headache, and gastrointestinal symptoms such as heartburn, nausea, and diarrhea.
Who: people using omega-3 supplements
Effect: mild side effects: taste, breath, sweat odor, headache, gastrointestinal symptoms
Certainty: Consumer summary; atrial fibrillation risk is not mentioned on this page (see ev-foinf-10).
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-foinf-13 · Position of an expert body · agency consumer fact sheet summarizing a 2022 review · n = 30 studies, 1,420 participants (cited review)
A 2022 review of 30 studies (1,420 participants) found eating foods rich in polyunsaturated fatty acids (PUFAs), especially omega-3s, may improve symptoms such as pain and swollen and tender joints, and might be an appropriate addition to drug therapy for rheumatoid arthritis.
Who: people with rheumatoid arthritis
Effect: may improve pain and swollen and tender joints; adjunct to drug therapy
Certainty: Adjunct, not replacement for drugs; T2 summary of a review, size of effect from T1 cards above.
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-foinf-14 · Position of an expert body · EU register entry · n = —
POL-HC-7039 EPA and DHA Omega-3 fatty acids Omega-3 EPA and DHA help maintain healthy joints Non-authorised
Who: EU food labeling
Effect: claim non-authorized
Certainty: Non-authorized means evidence did not meet the bar at assessment, not proof of no effect.
EU Register on nutrition and health claims, claim POL-HC-7039, snapshot 2026-09-21 · checked 2026-10-07 · we read the section
fshoil-r6-05 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs including unpublished data · n = 114592
A total of 35 randomized controlled trials (37 data sets; n=114 592) were included in this meta-analysis. 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: 35 RCTs, 114,592 participants aged 50 and older, at least 12 months, 500 mg/d or more
Effect: high risk, high dose OR 1.43 (1.14 to 1.79), absolute difference 0.8% (0.40% to 1.1%); low-dose groups OR 1.03 to 1.07, not significant
Certainty: newer than 34612056; includes unpublished data
Circ Arrhythm Electrophysiol, 2026 · checked 2026-10-03 · we read the abstract

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.