How much krill oil per day is appropriate depends on your individual health needs, dietary omega-3 intake, and the specific EPA and DHA content of your chosen supplement. Krill oil, derived from Antarctic krill, provides omega-3 fatty acids in a phospholipid form that may enhance absorption. Whilst there is no official UK recommended daily allowance for krill oil specifically, most clinical studies use doses between 500 mg and 2,000 mg daily. The key consideration is the actual EPA and DHA content rather than total oil weight. This article examines evidence-based dosing guidance, factors affecting individual requirements, safety considerations, and how to select a quality supplement in the UK market.

What Is Krill Oil and Why Do People Take It?

Krill oil is a marine-derived supplement extracted from Antarctic krill (Euphausia superba), small crustaceans that form a crucial part of the ocean food chain. Unlike standard fish oil, krill oil contains omega-3 fatty acids—primarily eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)—bound to phospholipids rather than triglycerides. This structural difference may enhance absorption, though the clinical significance of this potential advantage remains uncertain. Krill oil also naturally contains astaxanthin, a carotenoid antioxidant that gives the oil its characteristic red colour and may offer additional cellular protection.

People take krill oil primarily as a source of omega-3 fatty acids. Some research suggests omega-3s may help maintain cardiovascular health, though it's important to note that in the UK, NICE does not recommend omega-3 supplements for cardiovascular disease prevention. Some individuals use krill oil for joint health or inflammatory conditions, though evidence remains limited and mixed. Others take it for potential benefits related to cognitive function, mood regulation, and dry eye syndrome, although research in these areas is still emerging and inconsistent.

Common reasons people consider krill oil supplementation:

• As a source of omega-3 fatty acids for those with low dietary fish intake

• Joint health support

• General wellbeing maintenance

• Dry eye syndrome (though evidence is limited)

• Cognitive health (though evidence is inconsistent)

Whilst krill oil is widely available as an over-the-counter supplement in the UK, it is important to recognise that it is not a medicine and has not undergone the same rigorous regulatory approval process as pharmaceutical products. The Medicines and Healthcare products Regulatory Agency (MHRA) does not evaluate food supplements for efficacy, though manufacturers must comply with food safety regulations.

Recommended Daily Dosage of Krill Oil in the UK

There is no officially established recommended daily allowance (RDA) for krill oil specifically in the UK, as it is classified as a food supplement rather than a medicine. However, guidance can be drawn from research studies and recommendations for omega-3 fatty acid intake. The European Food Safety Authority (EFSA) suggests that a combined EPA and DHA intake of 250 mg per day is adequate for general health maintenance in adults. Many clinical trials investigating krill oil have used doses ranging from 500 mg to 3,000 mg daily, with most studies employing doses between 1,000 mg and 2,000 mg.

When considering krill oil dosage, it is essential to focus on the actual EPA and DHA content rather than the total oil weight. A typical 1,000 mg krill oil capsule may contain approximately 120–250 mg of combined EPA and DHA, depending on the brand. Therefore, to achieve the levels of omega-3 fatty acids used in research, individuals may need to take multiple capsules daily. Always check product labels for the specific EPA and DHA content per serving.

Doses commonly seen on supplement labels and in studies:

• General health maintenance: 500–1,000 mg krill oil daily (providing approximately 60–250 mg combined EPA/DHA)

• Higher intake levels: 1,000–2,000 mg daily (providing approximately 120–500 mg combined EPA/DHA)

• Upper ranges used in some studies: 2,000–3,000 mg daily (providing approximately 240–750 mg combined EPA/DHA)

It is advisable to start with a lower dose and gradually increase as tolerated. Krill oil can be taken with or without food, though taking it with meals may enhance absorption and reduce the likelihood of gastrointestinal discomfort. Always follow the manufacturer's instructions on the product label, and consult a GP or registered dietitian before exceeding recommended doses, particularly if you have existing health conditions or take prescribed medications. EFSA indicates that total supplemental EPA and DHA intake up to 5,000 mg per day is generally considered safe for adults, though such high doses should only be taken under medical supervision.

Factors That Affect How Much Krill Oil You Should Take

Individual krill oil requirements vary considerably based on several physiological, dietary, and clinical factors. Dietary omega-3 intake is perhaps the most significant consideration—individuals who regularly consume oily fish (such as salmon, mackerel, sardines, or herring) may require less supplementation. The NHS recommends at least two portions of fish per week, including one portion of oily fish, but many UK adults fall short of this target.

Body weight and metabolic factors also influence optimal dosing. Larger individuals may require higher absolute doses to achieve similar tissue concentrations of omega-3 fatty acids. People with certain metabolic conditions may wish to discuss omega-3 supplementation with their GP, as prescription options like icosapent ethyl (rather than over-the-counter supplements) may be recommended in specific clinical circumstances. Age-related changes in absorption and metabolism mean that older adults might benefit from adjusted dosing, though there is no official guidance establishing specific age-based recommendations for krill oil.

Certain health conditions and treatment goals may influence dosing considerations. However, it's important to note that krill oil supplements are not approved treatments for any medical conditions in the UK. People with bleeding disorders or those taking anticoagulant medications should consult their GP before taking krill oil due to omega-3's mild antiplatelet effects. Pregnancy and breastfeeding represent special circumstances where omega-3 requirements increase, but specific guidance should be sought from a midwife or GP. Pregnant women should avoid cod liver oil and other supplements high in vitamin A (retinol).

Medication interactions must be carefully considered. Krill oil may potentiate the effects of anticoagulants (warfarin, DOACs), antiplatelet agents (aspirin, clopidogrel), and some antihypertensive medications. Individuals taking these medications should consult their GP or pharmacist before starting supplementation. Those with shellfish allergies should exercise particular caution, as krill are crustaceans (shellfish) and may trigger allergic reactions in susceptible individuals.

Potential Side Effects and Safety Considerations

Krill oil is generally well tolerated by most individuals when taken at recommended doses, but like all supplements, it can cause adverse effects in some people. The most commonly reported side effects are gastrointestinal in nature, including mild nausea, diarrhoea, indigestion, and abdominal discomfort. These effects are typically dose-dependent and often resolve with continued use or by taking the supplement with food. Some individuals report a fishy aftertaste or burping, though this tends to be less pronounced with krill oil compared to traditional fish oil supplements.

Allergic reactions represent a more serious concern, particularly for individuals with known shellfish allergies. Krill are crustaceans (shellfish) and are recognised as a major allergen under UK food labelling law. Symptoms may range from mild skin reactions (rash, itching) to severe anaphylaxis in rare cases. Anyone with a history of seafood allergies should consult their GP or an NHS allergy clinic before using krill oil. If signs of an allergic reaction develop—such as facial swelling, difficulty breathing, or widespread urticaria—emergency medical attention should be sought immediately.

The antiplatelet effects of omega-3 fatty acids warrant careful consideration. Whilst this property may contribute to cardiovascular benefits, it can increase bleeding risk, particularly in individuals taking anticoagulant or antiplatelet medications. Caution is advised when total supplemental EPA and DHA intake exceeds 3,000 mg daily. Patients should inform their GP and dentist about krill oil use before surgical or dental procedures.

When to contact your GP:

• Persistent gastrointestinal symptoms lasting more than two weeks

• Signs of allergic reaction (rash, swelling, breathing difficulties)

• Unusual bruising or bleeding

• Before starting krill oil if you take anticoagulants, have a bleeding disorder, or are scheduled for surgery

• If you are pregnant, breastfeeding, or planning pregnancy

If you experience any suspected side effects from krill oil, you can report them through the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk). Krill oil supplements are not suitable for everyone, and professional medical advice should always take precedence over general supplementation guidance.

How to Choose a Quality Krill Oil Supplement

Selecting a high-quality krill oil supplement requires careful evaluation of several key factors, as the UK supplement market is not subject to the same stringent pre-market approval as medicines. Third-party testing and certification provide the most reliable assurance of quality. Look for products certified by independent organisations such as the Marine Stewardship Council (MSC) for sustainable sourcing, or those that have undergone testing by reputable laboratories or UKAS-accredited facilities. These certifications verify that the product contains what the label claims and is free from contaminants such as heavy metals, PCBs, and other marine pollutants.

The EPA and DHA content should be clearly stated on the label in milligrams per serving, not just the total krill oil weight. Quality products will provide transparent information about the omega-3 concentration, typically expressed as a percentage. Higher-quality krill oil supplements generally contain 20–30% omega-3 fatty acids by weight. Additionally, check for astaxanthin content, as this antioxidant is a natural component of krill oil that contributes to its stability and may offer additional benefits.

Manufacturing standards and traceability are crucial quality indicators. Reputable manufacturers should follow Good Manufacturing Practice (GMP) standards and provide information about the source of their krill (ideally Antarctic waters with sustainable harvesting practices). The product should be packaged in opaque or dark containers to protect the oil from light-induced oxidation, and capsules should be sealed in blister packs or bottles with desiccants to prevent moisture exposure.

Key quality markers to look for:

• Clear labelling of EPA and DHA content per serving (to compare across brands)

• Third-party testing certification (MSC, UKAS-accredited labs, or equivalent)

• Evidence of sustainable sourcing practices

• Manufactured to GMP standards

• Appropriate packaging to prevent oxidation

• Reasonable expiry date (indicating freshness)

• Transparent company information and contact details

• Proper allergen labelling (must declare crustaceans/shellfish)

• For pregnant women: check vitamin A (retinol) content is not excessive

Be cautious of products making exaggerated health claims or those significantly cheaper than comparable alternatives, as these may indicate inferior quality or inadequate omega-3 content. When in doubt, consult a pharmacist or registered dietitian who can recommend reputable brands available in the UK market.

Frequently Asked Questions