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Fish oil for joint pain

Goal: What trials in osteoarthritis and rheumatoid arthritis used, and why the effect on joint pain looks small.

Each protocol describes what studies used, for one goal or for one group of people. It is not advice for you: talk to a doctor before you start a supplement.

Updated 4 Nov 2026
Dose

A knee osteoarthritis trial compared 4.5 g and 0.45 g of omega-3 a day.[1] Rheumatoid arthritis trials gave about 3 g of EPA and DHA a day, as 10 g of fish oil in one trial.[2]

Form

Liquid fish oil, 15 mL a day, in the knee trial.[1]

How long

12 weeks to 2 years.[2][1]

What studies found

In osteoarthritis, a review of 9 trials and 2,070 patients found a small fall in pain.[3] In the 2-year knee trial, the high dose gave no extra benefit.[1] In rheumatoid arthritis, a review of 23 trials found a limited benefit, with very low to low certainty.[4]

Ask a doctor first

Fish oil may prolong clotting times when taken with warfarin, and more than 1.5 g a day raised atrial fibrillation in people at high heart risk.[2][5] People with rheumatoid arthritis should not change prescribed medicines without asking their doctor.[6]

People who take a blood thinner or other daily medicine should ask a doctor or pharmacist first.[2]

References

  1. Fish oil in knee osteoarthritis: a randomised clinical trial of low dose versus high dose. Hill CL, March LM, Aitken D, Lester SE, Battersby R, Hynes K, et al. Ann Rheum Dis, 2016. PMID 26353789
  2. Omega-3 Fatty Acids: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  3. Effect of omega-3 polyunsaturated fatty acids supplementation for patients with osteoarthritis: a meta-analysis. Deng W, Yi Z, Yin E, Lu R, You H, Yuan X J Orthop Surg Res, 2023. PMID 37226250
  4. Efficacy of n-3 fatty acid supplementation on rheumatoid arthritis' disease activity indicators: a systematic review and meta-analysis of randomized placebo-controlled trials. Gkiouras K, Grammatikopoulou MG, Myrogiannis I, Papamitsou T, Rigopoulou EI, Sakkas LI, et al. Crit Rev Food Sci Nutr, 2024. PMID 35900212
  5. Effects of Omega-3 Fatty Acid Treatment on Risk for Atrial Fibrillation: An Updated Meta-Analysis of 35 Trials including 114 592 Individuals. Abuknesha NR, O'Keefe JH, Qian F, Tintle NL, Lin Y, Sun Y, et al. Circ Arrhythm Electrophysiol, 2026. PMID 42517224
  6. Omega-3 Supplements: What You Need To Know. NIH National Center for Complementary and Integrative Health, 2024. www.nccih.nih.gov