Are Omega-3 Supplements Necessary? Who May Consider One and Who Probably Does Not
There is no universal need for omega-3 supplements. This page sets out what health bodies and large trials say about food first, and who may want to ask a clinician.
Content last updated . This page has not been medically reviewed.
The sources we read do not recommend omega-3 supplements for everyone. NHS advice is built around food: at least 2 portions of fish a week, including 1 of oily fish. [1] The US National Center for Complementary and Integrative Health (NCCIH) says that for some conditions the evidence for benefits from seafood is stronger than for omega-3 supplements. [2] Whether you personally should take one is a decision for you and a clinician or pharmacist. For a general food-first way to think, see Do I need a supplement?.
Food first
NHS says oily fish are the richest source of long-chain omega-3, and that oily fish are also a good source of vitamin D. [1] Shellfish such as oysters and crab contain some, but less. [1] For plant omega-3 (ALA), see flaxseed, walnuts and chia seeds, and for what foods and capsules compare on, omega-3 from food vs supplements.
What large reviews and trials found
Evidence labels: "evidence in adequately nourished people" means trials in general populations; "product-specific" means the result applies only to the product tested.
| Question | What the source found | Strength of evidence |
|---|---|---|
| Do EPA and DHA supplements prevent heart disease and early death in general? | A Cochrane review of 79 trials (112,059 people, 12 to 72 months) found moderate- and high-quality evidence that increasing EPA and DHA has little or no effect on mortality or cardiovascular health. [3] | Good quality; in adequately nourished and at-risk adults |
| What about healthy older adults? | In VITAL (25,871 US adults, marine omega-3 at 1 g per day versus placebo, median 5.3 years), supplementation did not result in fewer major cardiovascular events or cancers. [4] A secondary result for total heart attack was a hazard ratio of 0.72. [4] | Primary result null; secondary results are exploratory |
| What about high triglycerides? | NCCIH says there is some evidence that people with heart disease or high triglycerides may benefit from omega-3 supplements. [2] | Promising but limited |
| Does prescription icosapent ethyl help? | REDUCE-IT gave 4 g per day of icosapent ethyl, a purified EPA ethyl ester, to people with raised triglycerides on statins and found fewer ischemic events than placebo. [5] | Product-specific; not a result for over-the-counter fish oil |
| Do supplements help in pregnancy? | NCCIH says there is limited evidence that omega-3 supplementation during pregnancy has positive effects. [2] | Limited |
Proper evidence not found: we searched PubMed, NHS and NCCIH for a stated level of fish eating at which a supplement stops adding anything, and for a trial-based list of who benefits most. The sources do not give one.
Who may want to ask a clinician or pharmacist
- People who eat no fish or seafood, including vegetarians and vegans. See vegetarians and vegans and algal oil.
- People with heart disease or high triglycerides, where a clinician may discuss prescription options. See omega-3 and triglycerides.
- Pregnant or breastfeeding women. NHS advises avoiding fish liver oil supplements such as cod liver oil in pregnancy unless a GP advises otherwise, because of vitamin A. [1] See pregnancy and DHA.
Frequently asked questions
Should everyone take fish oil?
The sources do not recommend it. Cochrane found little or no effect of increasing EPA and DHA on mortality or cardiovascular health in the trials reviewed. [3]
Is fish oil better than eating fish?
NCCIH says for some conditions the evidence for seafood is stronger than for supplements. [2] We found no head-to-head trial in these sources.
Does the prescription trial apply to my fish oil capsule?
No. REDUCE-IT tested one purified EPA product at 4 g per day in a specific group. [5] Results should not be transferred to other products.
Can I get enough omega-3 without fish?
Plant foods provide ALA, but conversion to EPA and DHA is limited. [6] See algal oil.
Who decides if I need one?
A clinician or pharmacist who knows your medicines and health history.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety to know before buying
- NCCIH says side effects are usually mild and include unpleasant taste, bad breath, bad-smelling sweat, headache and gastrointestinal symptoms. [2]
- In REDUCE-IT, hospitalization for atrial fibrillation or flutter was higher with icosapent ethyl (3.1% versus 2.1%), and serious bleeding was 2.7% versus 2.1% (P=0.06). [5] That is one prescription product at 4 g per day, not other products, but it is why bleeding and rhythm questions go to a clinician. See fish oil, blood thinners and surgery.
- Tell your surgical team and pharmacist about any omega-3 product. The NCCIH page we read did not discuss drug interactions, so use medication interactions.
- Fish or shellfish allergy: see fish allergy and omega-3 products. Product quality: see quality testing.
References
- NHS, Fish and shellfish. United Kingdom. Read 2026-10-22.
- National Center for Complementary and Integrative Health (US), Omega-3 Supplements: What You Need to Know. Last updated November 2024. Read 2026-10-22.
- Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 2018. Read 2026-10-22.
- Marine n-3 fatty acids and prevention of cardiovascular disease and cancer (VITAL). N Engl J Med 2019. Read 2026-10-22.
- Cardiovascular risk reduction with icosapent ethyl for hypertriglyceridemia (REDUCE-IT). N Engl J Med 2019. Read 2026-10-22.
- Impact of alpha-linolenic acid supplementation on long-chain n-3 fatty acid profiles in Western, flexitarian, vegetarian, and vegan diets (NuEva study). Front Nutr 2025. Read 2026-10-22.