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ESRU

Krill oil

Phospholipid-bound omega-3 (EPA and DHA) with astaxanthin from Antarctic krill Euphausia superba, supplement

ATC code: C10AX-KRILL

Brand names – supplements: MegaRed Omega-3 Krill Oil, NOW Neptune Krill Oil, Source Naturals ArcticPure Krill Oil, Life Extension Krill OilSupplements are not tested in clinical trials and are not registered as medications.

Updated · Methodology

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

C

Cardiovascular prevention through supplements

Not recommended

Krill oil is an OTC supplement with claimed EPA/DHA load in fewer capsules than standard fish oil. in 2010 approved an EPA+DHA claim at 250 mg/day for normal heart function – the wording is source-agnostic (fish oil, krill oil, algal omega-3). No RCT has shown a krill-oil effect on hard cardiovascular outcomes (MI, stroke, CV death). Statins and non-pharmacological measures – blood-pressure and glucose control, smoking cessation, 150 min/week activity, Mediterranean diet – have orders-of-magnitude stronger evidence ( 2021, SEC 2022). If krill oil was bought to replace a prescribed statin, discuss with a cardiologist; stopping a statin in confirmed coronary disease multiplies infarction risk. EPA/DHA supplementation may be considered as an add-on in severe hypertriglyceridaemia above 5 mmol/L in agreement with the treating doctor.

Sources

  1. EFSA NDA Panel: Scientific Opinion on EPA and DHA contribution to the normal function of the heart (250 mg/day claim) (2010)
  2. Lipids (Ulven et al.): Metabolic effects of krill oil are essentially similar to those of fish oil, but at lower dose of EPA and DHA (2011)
  3. ESC: ESC Guidelines on cardiovascular disease prevention in clinical practice (2021)
  4. SEC: Sociedad Espanola de Cardiologia, comentario a las guias ESC 2021 de prevencion cardiovascular (2022)
D

Superfoods and adaptogens (marketing category)

Not recommended

Krill oil is marketed as a superfood and adaptogen, promising more energy, stress resilience, and general wellness from its phospholipid-bound omega-3s. The claims lack support: no good-quality studies confirm a benefit of krill oil as a "superfood" or "adaptogen". The substance itself is harmless in this use. To correct an omega-3 deficit or support heart health, talk to your doctor about approaches with real evidence, such as a diet with oily fish and, when indicated, omega-3 products with proven effects.

Sources

  1. Lipids Health Dis (Yurko-Mauro et al.): Similar omega-3 index increases with krill oil and fish oil in healthy adults (2015)
  2. Prostaglandins Leukot Essent Fatty Acids (Schuchardt et al.): Bioavailability of long-chain omega-3 fatty acids from different formulations: a review (2011)
  3. Lipids (Ulven et al.): Metabolic effects of krill oil are essentially similar to those of fish oil, but at lower dose of EPA and DHA (2011)
How to read tiers A–F
  • AStrong evidence – first or second line in international guidelines
  • BRecommended in selected cases
  • CStudy data contradict each other
  • DBenefit not proven, no documented harm
  • FDocumented harm, or risk without benefit

Mechanism of action

Krill is a small planktonic crustacean (Euphausia superba) from southern oceans. Krill oil delivers EPA and DHA bound to phospholipids (mainly phosphatidylcholine) rather than as ethyl esters or triglycerides as in standard fish oil. It also contains astaxanthin, a carotenoid that gives the red colour and protects omega-3 from oxidation. Manufacturers claim higher bioavailability of EPA/DHA from the phospholipid form, but at equivalent doses the omega-3 index (EPA+DHA fraction in red-blood-cell membranes) does not differ clinically (Yurko-Mauro 2015 RCT, Schuchardt 2011 review). approved an EPA+DHA claim at 250 mg/day for normal heart function – the wording covers all sources, not krill specifically. AEMPS has not registered krill oil as a medicine; in the EU and Spain it is a food supplement.

Safety

Contraindications

  • Known crustacean allergy (shrimp, crab, lobster, krill) – risk of anaphylaxis
  • High-dose warfarin or other anticoagulant therapy – bleeding risk
  • Severe hepatic failure
  • History of haemorrhagic stroke

Serious adverse effects

  • Anaphylaxis in crustacean-allergic users
  • Bleeding amplification when combined with high-dose anticoagulants

Common adverse effects

  • Fishy-tasting eructation
  • Gastrointestinal discomfort, mild diarrhoea
  • Taste disturbance

Pregnancy: can you take Krill oil?

Krill oil safety in human pregnancy has not been studied in RCTs. EPA and DHA are recommended in the diet during pregnancy (fish 1–2 times per week); the decision on separate supplements is made by the doctor. Crustacean allergy carries a risk of anaphylaxis. AESAN classifies krill oil as a complemento alimenticio without therapeutic indication.

Breastfeeding: can you take Krill oil?

Omega-3 fatty acids transfer into human milk during lactation; reasonable maternal intake benefits the infant. A separate krill-oil supplement is usually not needed if the mother eats a balanced diet.

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Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

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Frequently asked

What is Krill oil used for?

Krill oil is evaluated for the following indications with varying evidence strength: Cardiovascular prevention through supplements (evidence tier C), Superfoods and adaptogens (marketing category) (evidence tier D). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Krill oil?

Common side effects of Krill oil (≥ 1 in 100): Fishy-tasting eructation, Gastrointestinal discomfort, mild diarrhoea, Taste disturbance. See the Safety section for uncommon and serious reactions.

Is Krill oil safe during pregnancy?

Krill oil safety in human pregnancy has not been studied in RCTs. EPA and DHA are recommended in the diet during pregnancy (fish 1–2 times per week); the decision on separate supplements is made by the doctor. Crustacean allergy carries a risk of anaphylaxis. AESAN classifies krill oil as a complemento alimenticio without therapeutic indication.

Is Krill oil compatible with breastfeeding?

Omega-3 fatty acids transfer into human milk during lactation; reasonable maternal intake benefits the infant. A separate krill-oil supplement is usually not needed if the mother eats a balanced diet.

Who should not take Krill oil?

Krill oil is contraindicated in: Known crustacean allergy (shrimp, crab, lobster, krill) – risk of anaphylaxis; High-dose warfarin or other anticoagulant therapy – bleeding risk; Severe hepatic failure; History of haemorrhagic stroke. Full list in the Safety section.

Other drugs in this group

Lovastatin, Omega-3 triglycerides (EPA and DHA), Pitavastatin, Pravastatin, Rosuvastatin + Ezetimibe, Atorvastatin, Ezetimibe, Rosuvastatin