EPA vs DHA: the difference and which you need most

What is EPA?

EPA, eicosapentaenoic acid, is an omega-3 fatty acid with 20 carbon atoms. It is found in oily fish, shellfish and certain microalgae. In the body, EPA is used, among other things, as a raw material for signalling molecules involved in the body's normal fat metabolism.

EPA is also the fatty acid that usually dominates in natural fish oil. Together with DHA, EPA contributes to the normal function of the heart at an intake of at least 250 mg per day, and at 2 grams per day they contribute to the maintenance of normal blood triglyceride levels.

Despite the labels, EPA is not "the heart one" and DHA "the brain one" – that split is a simplification. Both are found throughout the body, and most of the authorised claims are based on the two working together. It is the whole that counts.

What is DHA?

DHA, docosahexaenoic acid, is longer – 22 carbon atoms – and is the omega-3 fatty acid the body stores most of in the brain and retina. Roughly 90 percent of the brain's omega-3 is DHA.

EFSA has authorised three claims specifically for DHA: it contributes to the maintenance of normal brain function, normal vision, and, in pregnant women, to the normal development of the brain and eyes of the foetus. That is why DHA is so often highlighted for pregnancy – more on that in our article on omega-3 during pregnancy.

Can the body convert EPA into DHA?

Partly. The body can elongate EPA into DHA and, conversely, break DHA down into EPA, but both processes are limited and vary between individuals. Women appear to convert somewhat more efficiently than men, probably linked to the demands of pregnancy. In practice, the conversion is still too small to rely on – which is why most supplements contain both EPA and DHA in ready-made form.

That is also why plant-based ALA is not enough. ALA must first become EPA and then DHA, and most of it is lost at each step. If you want to understand the whole chain, we explain it in why EPA and DHA matter so much.

EPA vs DHA – the differences at a glance

VitaNord Omega-3

Both EPA and DHA in one capsule – 180/120 mg – from MSC-certified fisheries, third-party tested.

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Which do you need most?

The answer depends on who you are, not on which fatty acid is "best":

• Pregnant or breastfeeding? DHA is the priority – the recommendation is 100–200 mg of extra DHA on top of the base intake.
• Mostly thinking about heart and blood lipids? The research has usually used EPA and DHA in combination, and the EFSA claim for the heart applies to them together.
• Focused on brain and vision? DHA carries the authorised claims here, at 250 mg of DHA per day.
• Rarely eat fish? Then you quite simply need both. Check the signs in our article on omega-3 deficiency.

What does the research say about EPA, DHA and mood?

Mood and low spirits are among the most-studied areas for omega-3, and EPA in particular has received the most attention. In several reviews, researchers have seen that formulations with a high proportion of EPA performed better than pure DHA products in studies on low mood. The findings are not clear-cut, however, and often involve higher doses than the reference intake.

Careful wording matters here: there is no authorised EFSA claim about omega-3 and mood, and supplements never replace treatment. If you find the area interesting, treat it as a developing field of research rather than an established effect.

Do you need to choose between EPA and DHA?

No. In fish they always occur together, and nearly all supplements contain both. VitaNord Omega-3 follows the natural profile with 180 mg of EPA and 120 mg of DHA per capsule. One capsule a day is therefore enough to clear the 250 mg reference intake. If you want to see how different products are composed, we have compared them in best omega-3.

How much of each should you take?

Count the total rather than fine-tuning the ratio:

• 250 mg EPA + DHA per day – the base level for adults
• 250 mg DHA per day – if you want to reach the claims for brain and vision
• 2 g EPA + DHA per day – the level EFSA links to normal triglycerides
• Max 5 g per day from supplements – the level EFSA has assessed as safe

The full reasoning, including dosing for children and pregnant women, is in omega-3 dosage: how much per day?

EPA, DHA and vegans

For those who do not eat fish, algae oil is the only direct source of ready-made EPA and DHA. Microalgae are rich in DHA, and several modern algae oils now contain EPA as well. Check the ingredient list – if it only says DHA, you are missing the EPA part.

Flaxseed, chia seeds and walnuts provide ALA but, as we have seen, only small amounts of EPA and DHA after conversion. They are good foods in other respects, but do not cover the need for long-chain omega-3 on their own. If you suspect you are running low, compare your symptoms with the list in omega-3 deficiency.

How to choose a product based on EPA and DHA

When comparing supplements, look at three things on the back of the label rather than the promises on the front:

• The amount of EPA and DHA per capsule – not the total amount of fish oil. It is EPA and DHA that count towards the reference intake.
• The balance between them – a natural fish oil often sits around 1.5:1 EPA to DHA, which suits most people.
• Purity and freshness – choose third-party tested, ideally with low oxidation values, so you avoid a rancid taste.

For most healthy adults, a standardised fish oil with both EPA and DHA is the simplest choice. If you need to prioritise DHA – during pregnancy, for example – you can pick a product with a higher DHA share, but the basic rule is that the 250 mg total is what matters most.

Frequently asked questions

Can you take only EPA or only DHA?

Concentrates with almost exclusively EPA or DHA exist, but for most people they are unnecessary. The fatty acids occur together in fish and work together in the body. EFSA's reference intake of 250 mg applies to EPA and DHA combined, so a combined supplement covers the need most easily.

Which is most important for the brain?

DHA. It is the most common omega-3 fatty acid in the brain's cell membranes, and EFSA has authorised the claim that DHA contributes to the maintenance of normal brain function at 250 mg per day. EPA is also present in the brain but at much lower levels, and has been studied more in other contexts.

Does the ratio between EPA and DHA matter?

For healthy people who want to cover the base requirement, the exact ratio matters less than the total amount. Natural fish oil often sits around 1.5:1 EPA to DHA. Researchers use different ratios when studying specific questions, but the 250 mg reference intake counts them as a whole.

Does algae oil contain both EPA and DHA?

It depends on the product. Microalgae are rich in DHA, and for a long time many algae oils contained DHA only. Today there are algae oils with both EPA and DHA – check the ingredient list. For vegans, algae oil is the only direct source of ready-made long-chain omega-3 fatty acids.

Sources

1. EFSA – Scientific Opinion on Dietary Reference Values for fats, including omega-3 (EFSA Journal 2010)
2. EFSA – Scientific Opinion on the Tolerable Upper Intake Level of EPA, DHA and DPA (EFSA Journal 2012)
3. Abdelhamid et al. – Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease (Cochrane, 2020)
4. Livsmedelsverket (Swedish Food Agency) – Fats: omega-3 and omega-6
5. Nordic Nutrition Recommendations, NNR 2023