EPA and DHA explained: how much omega-3 you actually need

Last reviewed 16 October 2026Next review April 20275 sources

EPA and DHA are the two omega-3 fatty acids that matter most in the fish-oil conversation — and the two letters worth understanding before you buy any omega-3 supplement, because a bottle can shout “1000mg of fish oil!” while quietly containing very little of either. This guide explains what EPA and DHA actually are, what the UK guidance says about fish and omega-3, how much you need for the officially recognised effects, and how to read an omega-3 label properly.

What are EPA and DHA?

EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are long-chain omega-3 fatty acids found mainly in oily fish and marine sources. They’re the forms your body puts directly to work. A third omega-3, ALA (alpha-linolenic acid), comes from plant sources like flaxseed and walnuts — but your body must convert ALA into EPA and DHA before using it that way, and the conversion is inefficient. That’s the practical reason fish sources and plant sources aren’t interchangeable, and why supplement labels list EPA and DHA separately.

These two carry officially authorised claims in Great Britain: EPA and DHA contribute to the normal function of the heart, and DHA contributes to the maintenance of normal brain function and normal vision. Each comes with a condition attached — the effect is obtained with a daily intake of 250mg of EPA and DHA (for the heart claim) or 250mg of DHA (for brain and vision). Keep that 250mg figure in mind; it’s the yardstick for reading any label.

What the NHS says about fish

The NHS guidance on fish and shellfish is the UK’s food-first position: aim for at least two portions of fish a week, at least one of which should be oily — salmon, mackerel, sardines, trout, herring. Oily fish is the guidance’s centre of gravity precisely because it’s where EPA and DHA live. If you reliably eat oily fish every week, you may not need a supplement at all. The realistic case for one is the same as ever: most people don’t consistently do the thing the guidance asks.

How much omega-3 per day?

There’s no official UK daily target for omega-3 in milligrams — the guidance is expressed in fish portions instead. But the authorised-claim conditions give you a defensible floor: 250mg of EPA and DHA a day is the intake at which the recognised heart-function effect applies. A weekly portion of oily fish averages out at roughly that order of magnitude per day, which is why the two framings broadly agree.

That figure is also your label-reading tool. Flip any omega-3 product over and find the EPA and DHA milligrams per serving — not the total fish-oil weight, which includes everything else in the oil. A “1000mg fish oil” capsule delivering 180mg EPA and 120mg DHA gives you 300mg of what counts. The front of the bottle tells you the oil; the back tells you the omega-3.

Omega-3 Plus: NeoLife’s fish oil

NeoLife Omega-3 Plus delivers 460mg of EPA and 480mg of DHA per three-capsule serving — comfortably clearing the 250mg conditions for the heart claim and the DHA brain-and-vision claims — alongside the other six omega-3 fatty acids naturally present in salmon oil.

The sourcing standard is the detail we’d point at first: the fish oils are screened for more than 200 potential contaminants, including mercury and lead, with an allowable detection limit of zero. A bottle holds 90 softgels — 30 days at the full three-capsule serving — for £38.00, which works out at £1.27 a day.

See Omega-3 Plus’s full details and order it here.

Fish oil vs. algae oil for vegans

EPA and DHA are made by marine algae; fish are rich in them because fish eat the algae. Algae-oil supplements go straight to that source, and they’re the only realistic way for vegans to get preformed EPA and DHA rather than relying on the inefficient ALA conversion. Our range doesn’t currently include an algae oil — if you’re vegan, that’s the label to look for elsewhere, and the same 250mg yardstick applies to it.

When to take omega-3

With a meal containing some fat — omega-3s are fats, and they absorb best in company. Taking fish oil on an empty stomach is also the classic cause of the “fishy burp”, so a mealtime habit solves two problems at once. If you take blood-thinning medication, speak to your GP or pharmacist before starting a fish-oil supplement — this article is general information, not medical advice.

Products in this guide

NeoLife Omega-3 Plus Fish Oil Supplement£38.00 Subscribe & save 10%View product

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