Omega-3 fatty acids

Can flaxseed oil replace fish oil?

Updated 9 Nov 2026

Short answer

Not as a source of EPA and DHA. Flaxseed oil provides ALA, 7.26 g per tablespoon, not EPA or DHA.[1] The body turns less than 15% of ALA into EPA and DHA.[1] Extra ALA raises EPA but has little effect on blood DHA.[2]

In a 2022 review of 13 trials, high doses of flaxseed oil did not raise the omega-3 index, while algae oil did.[3] ALA has its own small benefits: in a 2020 Cochrane review, more ALA probably slightly reduced arrhythmia.[4] Algae oil is a vegetarian source of DHA, and in one trial it raised blood DHA as much as cooked salmon.[5][6]

Sources (6)

  1. Omega-3 Fatty Acids: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  2. alpha-Linolenic acid supplementation and conversion to n-3 long-chain polyunsaturated fatty acids in humans. Brenna JT, Salem N Jr, Sinclair AJ, Cunnane SC Prostaglandins Leukot Essent Fatty Acids, 2009. PMID 19269799
  3. Bioavailability and conversion of plant based sources of omega-3 fatty acids - a scoping review to update supplementation options for vegetarians and vegans. Lane KE, Wilson M, Hellon TG, Davies IG Crit Rev Food Sci Nutr, 2022. PMID 33576691
  4. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Abdelhamid AS, Brown TJ, Brainard JS, Biswas P, Thorpe GC, Moore HJ, et al. Cochrane Database Syst Rev, 2020. PMID 32114706
  5. Omega-3 Supplements: What You Need To Know. NIH National Center for Complementary and Integrative Health, 2024. www.nccih.nih.gov
  6. Algal-oil capsules and cooked salmon: nutritionally equivalent sources of docosahexaenoic acid. Arterburn LM, Oken HA, Bailey Hall E, Hamersley J, Kuratko CN, Hoffman JP J Am Diet Assoc, 2008. PMID 18589030

More about omega-3 fatty acids

What are omega-3 fatty acids?What is the difference between ALA, EPA and DHA?What are omega-3 fatty acids used for?Which foods are high in omega-3?Are omega-3 supplements safe?Does plant omega-3 (ALA) protect the heart?

For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.