What EPA and DHA Do: The Evidence and the Authorised Claims
The omega-3 fats EPA and DHA, the health claims authorised in Great Britain with their doses, what is not allowed and what NICE and EFSA say.
Amazon links are paid links. As an Amazon Associate I earn from qualifying purchases. About these linksOmega-3 labels range from precise to vague. This guide explains which omega-3 fats are involved, which claims about EPA and DHA are authorised in Great Britain and under what conditions, what the register does not allow, and what NICE and EFSA say about the limits of the evidence. It is general information for adults, not medical advice. Our guide to choosing an omega-3 supplement covers the buying checks.
The omega-3 family in brief
Three omega-3 fats matter on labels. ALA (alpha-linolenic acid) is the plant one; the NHS lists linseed oil, rapeseed oil, chia seeds, hemp seeds and walnuts. EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are the long-chain omega-3 fats, and the NHS calls oily fish the richest source, with oysters and crab the main shellfish sources.
The three are not interchangeable on a label. A 2009 review for the International Society for the Study of Fatty Acids and Lipids found that ALA supplements raise EPA status in the blood but have little effect on DHA, and that improving blood DHA needs preformed DHA. So the EPA and DHA lines on the panel matter more than the word "omega-3".
Two intake figures give context. SACN's 2004 advice recommends a population average of 0.45 g a day of long-chain omega-3. EFSA's news release on its 2012 opinion says its dietary reference value work found 250 mg a day an adequate intake, and that adults in EU populations take in on average up to 400 to 500 mg a day from food.
The claims authorised in Great Britain
In Great Britain only claims on the nutrition and health claims register, published by the Department of Health and Social Care, may be used on food, and food supplements are food. The version we checked is dated 19 May 2026. Its omega-3 entries were carried over from EU decisions taken before 2021 (Regulation (EU) No 432/2012, 536/2013 and 440/2011). The register applies in Great Britain; DHSC guidance says EU nutrition-claims rules continue to apply in Northern Ireland, so this guide describes Great Britain. The authorised wordings and conditions are:
- "EPA and DHA contribute to the normal function of the heart." The food must be at least a source of omega-3 as the register defines it, which for EPA and DHA means at least 40 mg of the two together per 100 g and per 100 kcal. The consumer must be told the effect is obtained with a daily intake of 250 mg of EPA and DHA.
- "DHA contributes to maintenance of normal brain function" and "DHA contributes to the maintenance of normal vision." The food must contain at least 40 mg of DHA per 100 g and per 100 kcal, and the consumer must be told the effect is obtained with a daily intake of 250 mg of DHA.
- "DHA and EPA contribute to the maintenance of normal blood pressure." The food must provide 3 g a day of EPA and DHA. Supplements must tell consumers not to exceed a supplemental daily intake of 5 g of EPA and DHA combined, and the claim shall not be used for foods targeting children.
- "DHA and EPA contribute to the maintenance of normal blood triglyceride levels." The same conditions, with a daily intake of 2 g of EPA and DHA.
- "Docosahexaenoic acid (DHA) maternal intake contributes to the normal brain development of the foetus and breastfed infants," and the matching wording for the development of the eye. Pregnant and lactating women must be told the effect comes with 200 mg of DHA a day in addition to the recommended 250 mg of DHA and EPA, and the food must provide at least 200 mg of DHA.
- "ALA contributes to the maintenance of normal blood cholesterol levels." The food must be at least a source of ALA, with a daily intake of 2 g of ALA.
The wordings describe normal function, maintenance and development. None says omega-3 treats or prevents a disease, and each names a dose.
How to check a claim on a label
- Does the wording match? A paraphrase that adds a result is a different claim.
- Does a day's serving reach the dose? EFSA's news release says 2 to 4 g a day of EPA and DHA are needed for the blood pressure and triglyceride effects, and 250 mg a day for normal heart function. A product that supplies 300 mg a day does not meet the conditions for the 2 g or 3 g wordings.
- Is the condition stated? The consumer must be told the daily intake behind the effect.
- Is the audience right? The blood pressure and triglyceride wordings may not be used on foods targeting children; the maternal wording is for pregnant and breastfeeding women.
What the register does not authorise
The same register lists, as not authorised, wording that is common on supplement pages. It includes claims about joint mobility and flexibility, the immune system, emotional wellbeing and mood, concentration, healthy skin, weight control, "good" cholesterol and thinning the blood. It also lists as not authorised the general statements that omega-3 fatty acids "support a healthy heart" or help maintain a healthy cardiovascular system. The authorised wording is narrower: EPA and DHA, the normal function of the heart, and a stated daily intake. A label or advert in Great Britain cannot go beyond the register, however widely the topic is researched.
What guidance says about the limits
NICE's guideline on cardiovascular disease (NG238, December 2023) tells clinicians not to offer omega-3 fatty acid compounds to prevent cardiovascular disease, and to tell people that there is no evidence they help to prevent it. The exception is icosapent ethyl, a prescription medicine, used as described in a separate NICE appraisal. That is guidance on what clinicians offer for prevention; the authorised wordings above are about normal function and do not claim prevention. If your doctor has prescribed an omega-3 medicine, follow their directions, and if you take a supplement because of a heart or cholesterol concern, talk to your GP.
On safety, EFSA's 2012 opinion found the data insufficient to set an upper limit for EPA, DHA and DPA. It concluded that supplemental EPA and DHA together at up to 5 g a day raise no safety concern for adults, and said such intakes did not increase reported adverse effects such as bleeding episodes, impaired glucose regulation or impaired immune function. The FSA says not to exceed the label's dose, and that high-dose supplements should be taken only if a GP or healthcare specialist advises it. The NHS advises pregnant women to avoid fish liver oil supplements because of their vitamin A.
Food first
The NHS counts canned sardines, pilchards and tinned salmon as oily fish. Canned fish can be salty, depending on the brine or sauce, and our guide to salt and sodium on labels explains how to read it. The cards below come from our own product database, which is built from Open Food Facts contributors' entries and can contain errors. They show tinned sardines, lowest sodium per 100 g first. Read the label of the tin you choose, and see our list of low-sodium products.
Photos: Open Food Facts contributors, CC BY-SA 3.0
Using this when you shop
When you compare supplements, check that the EPA and DHA lines are stated, that any claim matches the wording above including its dose, and that the label carries the standard supplement warnings. Searches such as omega-3 fish oil capsules on Amazon (opens in a new tab) and vegan omega-3 algae oil on Amazon (opens in a new tab) show many listings, and the label on the pack, not the listing, is what counts. Our guide to fish oil and algae oil compares the sources, and the one on oxidation, mercury and labels covers freshness.
Your GP or pharmacist is the right person to ask if you have a health condition or take medicines, and the label is the authority on dose and warnings.