Fish, algae or krill: where omega-3 comes from – and what EFSA says about DHA in 2026

Fish oil, algae oil, krill oil: all three supply the long-chain omega-3 fatty acids EPA and DHA – yet they differ in origin, structure and the evidence behind them. In January 2026, the European Food Safety Authority (EFSA) also published its assessment of supplemental DHA. This article provides a factual overview of what research has observed about the different sources and what EFSA actually states.

Fish oil, algae oil and krill oil supply the same fatty acids in different forms

EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are long-chain omega-3 fatty acids. They are originally produced by microalgae; fish and krill take them up through the food chain and store them in their tissues. Plant oils such as flaxseed oil, by contrast, contain alpha-linolenic acid (ALA), a short-chain omega-3 fatty acid – it is not the subject of this article. The basics of EPA and DHA are covered in our article on omega-3 and algae oil.

The three sources differ mainly in the chemical form in which the fatty acids occur and in the ratio of EPA to DHA:

Source	Origin	Form of the fatty acids	Typical pattern	Worth noting
Fish oil	Oily marine fish	Mainly triglycerides; in supplements also as ethyl esters or re-esterified triglycerides	Usually more EPA than DHA	Animal origin; fish allergy
Algae oil	Cultivated microalgae	Natural triglycerides	Usually more DHA; EPA content varies by product	No animal origin
Krill oil	Antarctic krill	Around 30–65% of the fatty acids as phospholipids	EPA and DHA	Crustacean; shellfish allergy

Whether these differences matter for the body has been examined in several studies using blood values. They measure how much EPA and DHA reaches the bloodstream after intake – known as bioavailability.

Algae oil and fish oil lead to comparable DHA levels in the blood in studies

In a randomised, open-label human study (RCT) with 32 healthy adults, DHA from algae oil capsules was compared over two weeks with DHA from cooked salmon, 600 mg DHA per day in each case. The DHA share in plasma phospholipids rose by about 80% in both groups, and by about 25% in red blood cells. The authors considered the two sources equivalent in this respect. Note that the comparator was salmon, not fish-oil capsules.

A more recent RCT (double-blind, placebo-controlled) with 74 adults provides a direct comparison with fish oil. After 6 and 14 weeks, the researchers measured fatty acids in plasma phospholipids. The uptake of DHA and EPA from microalgae oil was statistically non-inferior to fish oil. The authors work for a supplier of algae oil; independent comparison studies would further support the finding.

Both studies have this in common: they record blood values, not health outcomes. No conclusions about effects in the body can be drawn from them.

For krill oil, the evidence on absorption is inconsistent

Krill oil contains a large share of its fatty acids in the form of phospholipids. This led to the assumption that EPA and DHA might be absorbed better from it. The studies do not paint a uniform picture.

An RCT with 15 healthy people (single dose, cross-over, around 1,700 mg EPA and DHA) found higher plasma values over 72 hours after krill oil than after fish oil. According to an industry report, the study was sponsored by the maker of a krill product. Krill meal with an identical fat composition, however, only reached the level of fish oil – the authors themselves see this as an argument against the phospholipid explanation. A four-week, double-blind RCT concluded that fish-oil and krill-oil products achieved similar EPA and DHA levels in plasma and red blood cells; this study, too, comes from the environment of a manufacturer.

A narrative review that evaluated 14 original studies notes that absorption from krill oil and fish oil may differ, but that interpretation remains difficult because of differing doses and study designs. Whether krill oil delivers more EPA and DHA to the blood at the same dose has therefore not been conclusively settled.

In January 2026, EFSA did not set an upper limit for DHA but confirmed its safe level of intake

At the request of the European Commission, EFSA reviewed the safe level of intake for supplemental DHA that contains DHA alone or mostly DHA. To do so, it evaluated human studies in which DHA was given for at least eight weeks. As the critical effect, it selected the risk of spontaneous bleeding.

The outcome has two parts:

• A tolerable upper intake level (UL) cannot be established for any population group because data on the relationship between dose and effect are lacking.
• Instead, EFSA confirms the safe level of intake of 1 g per day already set in 2012. It applies to all population groups, including infants, children, adolescents, adults, and pregnant and breastfeeding women.

The distinction matters: the safe level describes amounts at which no adverse effects were observed in the studies evaluated. It does not name an amount above which risks begin. According to an industry report, EFSA also acknowledges that direct clinical evidence of spontaneous bleeding under DHA is limited.

The value applies regardless of the chemical form of the fatty acids (triglycerides, ethyl esters, phospholipids) and regardless of the source – fish oil concentrates, algae oils and krill oils are expressly named. The prerequisite is that the product contains DHA alone or mostly DHA, meaning the ratio of EPA to DHA is below 0.3. For combinations with a higher EPA share, this opinion does not apply in this form. For such combinations, EFSA’s 2012 assessment is the reference: supplemental intakes of EPA and DHA combined of up to 5 g per day did not raise safety concerns for adults.

Safety and use: what to look out for with omega-3 supplements

• Blood-thinning medication and surgery: Because EFSA chose the risk of spontaneous bleeding as the critical effect, it is advisable to speak to a doctor before taking supplements alongside anticoagulants or ahead of planned procedures.
• Pregnancy, breastfeeding and children: EFSA states its safe level for these groups as well. Taking supplements should nevertheless be discussed with a healthcare professional.
• Total intake: EPA and DHA are also found in fish and fortified foods. Do not exceed the daily dose stated on the packaging.
• Allergies: Fish oil comes from fish, krill oil from crustaceans. Algae oil is not affected.
• Tolerability: Digestive discomfort can occur in individual cases.
• Freshness: In 2012, EFSA assumed that the oxidative stability of the fatty acids is ensured. Light-protective packaging and manufacturer information on testing are therefore useful indicators.

Anyone wishing to avoid animal sources will find an alternative in algae oil from cultivated microalgae. How much EPA and DHA a daily dose contains is stated on the packaging and should be the main point of comparison between products.

Comparable DHA uptake from algae and fish oil is shown – much remains open for krill oil and high DHA amounts

The studies show similar blood levels of DHA and EPA for algae oil and fish oil; however, part of the work comes from the environment of manufacturers, and blood values rather than health outcomes were measured. For krill oil, the evidence is inconsistent. In January 2026, EFSA confirmed that 1 g per day is considered safe for DHA alone or mostly DHA, but that a formal upper limit cannot be derived for lack of data. Where risks begin at higher amounts remains open. The choice of a source therefore comes down mainly to personal criteria such as diet, allergies and the composition of the individual product.

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This article is for general information about omega-3 sources and EFSA’s assessment of supplemental DHA and does not replace medical advice, diagnosis or treatment. If you have health concerns, please consult a doctor or pharmacist.

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Sources

• EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) (2026): Scientific Opinion on the tolerable upper intake level for supplemental docosahexaenoic acid. EFSA Journal 24:e9858 (official scientific opinion, published 14 Jan 2026). doi:10.2903/j.efsa.2026.9858
• EFSA Panel on Dietetic Products, Nutrition and Allergies (2012): Scientific Opinion on the Tolerable Upper Intake Level of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA). EFSA Journal 10(7):2815. doi:10.2903/j.efsa.2012.2815
• Arterburn LM et al. (2008): Algal-oil capsules and cooked salmon: nutritionally equivalent sources of docosahexaenoic acid. J Am Diet Assoc 108(7):1204–1209 (RCT, human). PMID 18589030
• Bailey E et al. (2025): Comparative Bioavailability of DHA and EPA from Microalgal and Fish Oil in Adults. Int J Mol Sci 26(19):9343 (RCT, human). doi:10.3390/ijms26199343
• Köhler A et al. (2015): Bioavailability of fatty acids from krill oil, krill meal and fish oil in healthy subjects – a randomized, single-dose, cross-over trial. Lipids Health Dis 14:19 (RCT, human). PMID 25884846
• Similar eicosapentaenoic acid and docosahexaenoic acid plasma levels achieved with fish oil or krill oil in a randomized double-blind four-week bioavailability study. Lipids Health Dis 14:99 (2015) (RCT, human). doi:10.1186/s12944-015-0109-z
• Ulven SM, Holven KB (2015): Comparison of bioavailability of krill oil versus fish oil and health effect. Vasc Health Risk Manag 11:511–524 (narrative review). PMID 26357480
• NutraIngredients (23 Jan 2026): EFSA sets ‘conservative’ safe intake level for DHA (industry report). nutraingredients.com
• NutraIngredients (13 Apr 2015): Superior bioavailability? Study backs krill oil over fish oil … but not because of phospholipids (industry report, information on study funding). nutraingredients.com