Omega-3 fatty acidsAre omega-3 supplements safe?
Short answer
Side effects are usually mild: an unpleasant taste, bad breath, heartburn, nausea, stomach upset, diarrhea, headache and smelly sweat.[1][2] EFSA and the US FDA consider up to 5 g of EPA and DHA a day safe for adults.[3][1]
Two large trials gave 4 g a day for several years to people with heart disease or at high risk of it. They found slightly more atrial fibrillation, an irregular heartbeat.[1] Fish oil may prolong clotting times in people who take warfarin, and labels of prescription omega-3 advise regular checks of INR, a clotting test, with blood thinners.[1] Cod liver oil also contains vitamins A and D, which can be harmful in large amounts.[2] Omega-3 supplements have not been found to contain mercury, because processing removes it.[1]
Sources (3)
- Omega-3 Fatty Acids: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
- Omega-3 Supplements: What You Need To Know. NIH National Center for Complementary and Integrative Health, 2024. www.nccih.nih.gov
- Scientific Opinion on the Tolerable Upper Intake Level of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA). European Food Safety Authority, 2012. efsa.onlinelibrary.wiley.com
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?Does plant omega-3 (ALA) protect the heart?Does omega-3 lower blood pressure?For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.