Krill Oil

• Cardiovascular health
• Anti-inflammatory
• Cognitive function support
• Metabolic health

• Joint health
• Women’s health (PMS symptoms)
• Eye health
• Skin health
• Liver health

Krill oil exerts its biological effects through a unique combination of bioactive components, primarily phospholipid-bound omega-3 fatty acids (eicosapentaenoic acid/EPA and docosahexaenoic acid/DHA), astaxanthin, and choline. The distinctive phospholipid structure of krill oil, where approximately 30-65% of omega-3 fatty acids are bound to phospholipids (primarily phosphatidylcholine) rather than triglycerides, is central to its mechanism of action and differentiates it from fish oil. This phospholipid structure enhances the incorporation of EPA and DHA into cell membranes, as phospholipids are the primary structural components of all cellular membranes. When integrated into cell membranes, these omega-3 fatty acids alter membrane fluidity, organization of lipid rafts, and function of membrane proteins, including receptors, ion channels, and enzymes.

The phospholipid delivery system also facilitates more efficient transport of EPA and DHA across the blood-brain barrier, potentially enhancing neurological benefits. Like fish oil, krill oil’s omega-3 fatty acids compete with arachidonic acid (AA) for cyclooxygenase (COX) and lipoxygenase (LOX) enzymes, reducing the production of pro-inflammatory eicosanoids derived from AA while promoting the synthesis of less inflammatory or actively anti-inflammatory eicosanoids. EPA and DHA also serve as precursors for specialized pro-resolving mediators (SPMs), including resolvins, protectins, and maresins, which actively resolve inflammation. Krill oil’s omega-3s modulate gene expression through interaction with transcription factors, particularly peroxisome proliferator-activated receptors (PPARs) and sterol regulatory element-binding proteins (SREBPs), affecting genes involved in lipid metabolism, inflammation, and cellular differentiation.

They also inhibit the activation of nuclear factor-kappa B (NF-κB), a key transcription factor that regulates the expression of pro-inflammatory cytokines. A unique aspect of krill oil is its natural content of astaxanthin, a potent antioxidant carotenoid that protects the highly unsaturated fatty acids from oxidation and provides additional anti-inflammatory effects through multiple pathways, including inhibition of NF-κB activation and reduction of pro-inflammatory cytokine production. Astaxanthin also crosses the blood-brain barrier, potentially providing neuroprotective effects. The high phosphatidylcholine content in krill oil provides a bioavailable source of choline, an essential nutrient for liver function, neurotransmitter synthesis, cell membrane integrity, and methylation reactions.

Choline is a precursor to acetylcholine, a neurotransmitter involved in memory and muscle control, and is essential for the transport and metabolism of lipids and cholesterol from the liver. In cardiovascular health, krill oil reduces triglyceride synthesis in the liver, improves endothelial function, reduces platelet aggregation, and may help maintain healthy cholesterol levels through effects on PPAR activation and hepatic lipid metabolism. For brain function, the phospholipid-bound DHA in krill oil may be particularly effective at supporting neuronal membrane structure and function, influencing neurotransmission, synaptic plasticity, and potentially supporting cognitive health.

The optimal dosage of krill oil is typically expressed in terms of the combined EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) content, with consideration for the phospholipid delivery system that enhances bioavailability. For general health maintenance, 250-500 mg of combined EPA and DHA from krill oil daily is recommended. Due to the enhanced bioavailability of phospholipid-bound omega-3s, these doses may provide effects comparable to higher doses of fish oil. For therapeutic purposes, higher doses ranging from 1,000-2,000 mg of EPA+DHA daily from krill oil are often used, depending on the specific condition being addressed.

It’s important to note that a 1,000 mg krill oil capsule typically contains only 200-300 mg of combined EPA and DHA, so multiple capsules may be needed to reach therapeutic doses.

Krill oil demonstrates enhanced bioavailability compared to conventional fish oil, primarily due to its unique phospholipid structure. While fish oil contains omega-3 fatty acids primarily in triglyceride or ethyl ester forms, approximately 30-65% of the omega-3 fatty acids in krill oil are bound to phospholipids, predominantly phosphatidylcholine. This structural difference significantly impacts absorption and cellular uptake. Human and animal studies suggest that the phospholipid-bound omega-3s in krill oil may have 1.5-3 times greater bioavailability than triglyceride or ethyl ester forms found in fish oil.

This enhanced absorption is attributed to several factors: phospholipids are amphipathic molecules (having both hydrophilic and hydrophobic regions) that can form micelles in the aqueous environment of the digestive tract without requiring bile salts, making them less dependent on fat digestion for absorption; phospholipids are integral components of cell membranes, facilitating direct incorporation of the attached omega-3 fatty acids into cellular membranes; and the phospholipid structure may protect the omega-3 fatty acids from oxidation and enzymatic degradation during digestion. Additionally, the natural presence of astaxanthin in krill oil may further protect the omega-3 fatty acids from oxidation, preserving their bioactivity during digestion and metabolism.

Taking with a meal containing some fat may still improve absorption, though the phospholipid structure makes krill oil less dependent on dietary fat for absorption compared to fish oil, Ensuring the product contains a significant proportion of phospholipid-bound omega-3s (look for products specifying phospholipid content), Selecting products with adequate astaxanthin content, which helps protect the omega-3s from oxidation during storage and digestion, Emulsified krill oil products may further enhance absorption by increasing the surface area available for enzymatic action, Liposomal delivery systems may improve cellular uptake of the fatty acids, though the natural phospholipid structure already provides similar benefits, Dividing larger doses throughout the day may improve overall absorption compared to a single large dose, Ensuring adequate vitamin D status, as vitamin D may enhance the cellular effects of omega-3 fatty acids, Avoiding simultaneous intake with high-fiber supplements, which might bind to the oil and reduce absorption

Krill oil can be taken with or without food, though taking it with meals may reduce the potential for digestive discomfort and slightly enhance absorption. Unlike ethyl ester forms of fish oil, which show significantly reduced bioavailability when taken on an empty stomach, the phospholipid structure of krill oil makes it less dependent on concurrent fat consumption for effective absorption. For larger therapeutic doses (>1 gram EPA+DHA), dividing the dose between two or three meals throughout the day may improve overall absorption and reduce potential gastrointestinal side effects compared to a single large dose. Morning or midday administration is often preferred over evening dosing, as some individuals report sleep disturbances or vivid dreams when taking omega-3 supplements before bed, though this effect varies between individuals.

For cardiovascular benefits, consistent daily dosing is more important than specific timing. For inflammatory conditions, maintaining steady blood levels through consistent daily dosing is recommended. For PMS symptoms, some research suggests starting supplementation 7-10 days before expected menstruation and continuing throughout the cycle may be most effective. If taking multiple supplements, separating krill oil from iron supplements by at least 2 hours may be prudent, as iron can potentially promote oxidation of the omega-3 fatty acids, though the astaxanthin in krill oil provides some protection against this effect.

• Gastrointestinal discomfort (nausea, indigestion, diarrhea, abdominal pain) – generally milder than with fish oil
• Fishy aftertaste or burping (less common than with fish oil due to astaxanthin content and phospholipid structure)
• Allergic reactions in individuals with shellfish or crustacean allergies
• Increased risk of bleeding at high doses (>2g EPA+DHA daily)
• Potential for increased LDL cholesterol in some individuals (rare)
• Mild skin reactions (rare)
• Halitosis (bad breath) – less common than with fish oil

• Shellfish or crustacean allergies (krill is a crustacean)
• Bleeding disorders or hemophilia
• Scheduled surgery (discontinue 1-2 weeks prior)
• Uncontrolled hypotension (low blood pressure)
• Severe liver disease
• Bipolar disorder manic phase (may potentially worsen manic symptoms)
• Pregnancy and breastfeeding (insufficient safety data)
• Seafood allergies (use with caution)

• Anticoagulant and antiplatelet medications (warfarin, aspirin, clopidogrel) – may increase bleeding risk
• Blood pressure medications – may enhance hypotensive effects
• Orlistat and other lipase inhibitors – may reduce absorption, though potentially less than with fish oil due to the phospholipid structure
• Vitamin E supplements – potential additive anticoagulant effects
• Glucocorticoids – may reduce the immunomodulatory effects
• Contraceptive drugs – theoretical interaction affecting hormone levels
• Diabetes medications – may enhance glucose-lowering effects, requiring monitoring
• Estrogen-containing medications – potential interaction due to effects on lipid metabolism

The upper limit for safe consumption of krill oil has not been as clearly established as for fish oil, but similar guidelines are generally applied. Doses providing up to 2 grams of EPA and DHA combined per day from krill oil are considered generally safe for most adults. Due to the enhanced bioavailability of the phospholipid-bound omega-3s in krill oil, lower doses may provide effects comparable to higher doses of fish oil, potentially reducing the risk of side effects. At higher doses, increased risk of bleeding and potential immunosuppressive effects become more significant concerns.

Individuals with specific health conditions (particularly bleeding disorders, compromised immune function, shellfish allergies, or uncontrolled hypotension) should avoid krill oil or use only under medical supervision. The astaxanthin content in krill oil provides antioxidant protection that may reduce the risk of lipid peroxidation compared to fish oil, potentially improving the safety profile at equivalent omega-3 doses. Quality is a critical safety consideration, as with all marine oils. Products should be tested for environmental contaminants including heavy metals, PCBs, and dioxins, with levels below established safety thresholds.

Sustainable harvesting practices are also an important consideration, as krill is a keystone species in the Antarctic ecosystem.

In the United States, krill oil is regulated as a dietary supplement under the Dietary Supplement Health and Education Act (DSHEA) of 1994. Under this framework, manufacturers cannot make specific claims about treating, curing, or preventing diseases, but can make structure/function claims about effects on normal body functions (e.g., ‘supports heart health’). These claims must be accompanied by a disclaimer stating they have not been evaluated by the FDA. The FDA has not established a specific recommended daily allowance for krill oil, but generally applies the same safety guidelines as for other marine omega-3 supplements, considering doses up to 3 grams of EPA and DHA combined per day from supplements to be generally safe.

In 2004, the FDA acknowledged a qualified health claim for conventional foods and dietary supplements containing EPA and DHA omega-3 fatty acids, stating that ‘supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease.’ This claim can be applied to krill oil products that provide EPA and DHA. Unlike fish oil, which has been granted Generally Recognized as Safe (GRAS) status for certain applications, krill oil does not currently have FDA GRAS status. However, several krill oil manufacturers have received FDA ‘no questions’ letters in response to their GRAS notifications for specific krill oil ingredients, effectively allowing their use in certain food applications beyond supplements.

Eu: In the European Union, krill oil is regulated as a food supplement under the Food Supplements Directive (2002/46/EC). The European Food Safety Authority (EFSA) has approved several health claims for EPA and DHA under Regulation (EC) No 1924/2006, which can be applied to krill oil products that provide sufficient amounts of these omega-3 fatty acids. These include claims related to normal heart function, blood pressure, triglyceride levels, and brain development. Specifically, foods providing at least 250 mg of EPA and DHA per day can claim to contribute to ‘normal heart function,’ and foods with 250 mg DHA can claim to contribute to ‘normal brain function’ and ‘normal vision.’ The EU has established a tolerable upper intake level of 5 grams of combined EPA and DHA per day from all sources. Krill harvesting is also subject to regulations under the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), which sets catch limits and monitors the sustainability of the Antarctic krill fishery.

Canada: Health Canada regulates krill oil as a Natural Health Product (NHP). Krill oil products must have a Natural Product Number (NPN) on the label, indicating they have been assessed by Health Canada for safety, efficacy, and quality. Health Canada has approved specific claims for krill oil products, including supporting cardiovascular health and reducing serum triglycerides. The recommended intake for general health is similar to other omega-3 sources, at approximately 500 mg of combined EPA and DHA per day. Health Canada has also recognized the enhanced bioavailability of krill oil’s phospholipid-bound omega-3 fatty acids in some of its product licensing decisions.

Australia: The Therapeutic Goods Administration (TGA) regulates krill oil as a listed complementary medicine. Products must be included in the Australian Register of Therapeutic Goods (ARTG) and comply with quality and safety standards. The TGA allows certain health claims for krill oil supplements based on evidence levels, including claims related to cardiovascular health, anti-inflammatory effects, and brain function. The TGA has also recognized the unique phospholipid structure of krill oil in its evaluation of these products.

Japan: In Japan, krill oil is regulated under the Foods with Function Claims (FFC) system, which allows for certain health claims based on scientific evidence without the strict approval process required for Foods for Specified Health Uses (FOSHU). Krill oil products can make claims related to triglyceride reduction and cardiovascular health if they provide sufficient scientific evidence. Japan has particularly strict standards regarding oxidation parameters for marine oils, including krill oil.

Norway: As a major producer of krill oil products, Norway has specific regulations for krill oil quality and sustainability. The Norwegian Food Safety Authority (Mattilsynet) regulates krill oil as a food supplement and has established quality standards for these products. Norwegian companies are also subject to strict sustainability requirements for krill harvesting under international agreements.

High

Krill oil is generally more expensive than conventional fish oil, with prices typically 2-4 times higher for equivalent amounts of EPA and DHA. The cost of krill oil supplements ranges from $0.50-$1.50 per gram of oil, or approximately $1.00-$3.00 per day for a standard dose providing 250-500 mg of EPA+DHA. Premium brands with higher phospholipid content, astaxanthin levels, and sustainability certifications may cost $2.00-$4.00 per day for a similar EPA+DHA dose. When calculated based on the actual EPA+DHA content (rather than total oil), the cost ranges from $2.00-$6.00 per gram of EPA+DHA, compared to $0.50-$2.00 per gram for fish oil.

This price premium reflects the higher production costs associated with Antarctic krill harvesting, specialized extraction methods required to preserve the phospholipid structure, and the additional value of the naturally occurring astaxanthin and phospholipids.

The value proposition of krill oil depends largely on whether its unique properties—phospholipid structure, astaxanthin content, and potentially enhanced bioavailability—justify the significant price premium over conventional fish oil. For general omega-3 supplementation and primary cardiovascular prevention, standard fish oil likely offers better cost efficiency for most consumers. However, krill oil may provide better value in specific situations: For individuals who experience digestive discomfort or ‘fishy burps’ with standard fish oil, krill oil’s phospholipid structure and astaxanthin content typically result in better tolerability and reduced reflux, potentially justifying the higher cost. For those seeking enhanced absorption efficiency, particularly individuals with compromised fat digestion or absorption, the phospholipid delivery system may provide better omega-3 incorporation with lower doses.

Some clinical studies suggest that lower doses of krill oil may provide comparable benefits to higher doses of fish oil for certain conditions, particularly lipid management and women’s health (PMS symptoms). If this enhanced potency is consistently demonstrated in larger studies, it could improve krill oil’s cost-efficiency calculation. The additional benefits of astaxanthin (antioxidant protection) and phosphatidylcholine (source of choline) provide value beyond the omega-3 content alone, essentially providing multiple supplements in one product. For environmental and sustainability considerations, certified sustainable krill oil may offer better value for environmentally conscious consumers, as the Antarctic krill fishery is generally considered well-managed compared to some fish oil sources.

The phospholipid structure may provide advantages for specific applications like cognitive health due to enhanced delivery across the blood-brain barrier, potentially offering better value for this specific application despite the higher cost. Overall, krill oil represents a premium omega-3 option that may be worth the additional cost for specific populations or applications, but for general omega-3 supplementation, conventional fish oil typically offers better cost efficiency. Consumers should weigh the potential benefits of krill oil’s unique properties against the significant price premium when making purchasing decisions.

Properly manufactured and stored krill oil typically has a shelf life of 18-24 months from the date of manufacture when in softgel form. Liquid krill oil (though less common than softgels) generally has a shorter shelf life of 6-12 months after opening due to increased exposure to oxygen. The natural presence of astaxanthin in krill oil provides significant antioxidant protection, potentially extending its shelf life compared to standard fish oil without added antioxidants. However, the high polyunsaturated fatty acid content still makes krill oil susceptible to oxidation over time.

Products with higher astaxanthin content (>1.5 mg/g) generally demonstrate better stability and longer shelf life. The phospholipid structure of krill oil may provide some inherent stability advantages over triglyceride-based oils, as the phosphate head groups can form protective structures around the vulnerable fatty acid chains. However, once oxidation begins, it can progress rapidly through an autocatalytic process.

Store krill oil supplements in their original, airtight container away from direct sunlight, heat sources, and moisture. Refrigeration is recommended, particularly after opening, as lower temperatures significantly slow oxidation reactions. Even unopened softgel products benefit from refrigeration, though room temperature storage in a cool, dark place is generally acceptable if the temperature remains below 25°C (77°F). Freezing krill oil is acceptable and may further extend shelf life without damaging the oil, though it may affect the integrity of some softgel capsules.

Minimize exposure to air by keeping containers tightly closed when not in use. For liquid krill oil products, consider transferring to smaller containers as you use it to minimize the air space in the bottle. Avoid storing near strong-smelling substances as krill oil can absorb odors, though this is less of an issue than with fish oil due to the astaxanthin content, which reduces the fishy odor. If capsules develop a strong, unpleasant smell or taste extremely bitter or ‘off,’ this indicates oxidation and they should be discarded.

Dark, opaque bottles with nitrogen-flushed headspace provide the best protection for liquid krill oil products. When traveling with krill oil, consider using insulated containers if exposure to high temperatures is likely.

Oxygen exposure (primary degradation pathway through oxidation of unsaturated fatty acids), Heat (accelerates oxidation reactions; each 10°C increase approximately doubles the rate of degradation), Light exposure (particularly UV light, which promotes photo-oxidation of unsaturated fatty acids), Transition metal ions (especially iron and copper, which catalyze oxidation reactions), Moisture (can promote hydrolytic rancidity and microbial growth in liquid products), Repeated opening of containers (increases oxygen exposure), Fluctuating temperatures (can cause condensation inside containers, promoting degradation), Extended storage beyond expiration date (natural antioxidants in the oil deplete over time), Improper packaging materials (some plastics may allow oxygen permeation), Pre-existing oxidation products (oxidation is autocatalytic, so products with initial oxidation degrade faster), Higher EPA and DHA concentration (more polyunsaturated fatty acids means more sites for oxidation), Depletion of astaxanthin (as this natural antioxidant is consumed protecting the oil, stability decreases), Exposure to environmental pollutants or strong odors (oil can absorb contaminants), Enzymatic degradation (more relevant in liquid products without proper preservatives)

Synthesis Methods

Natural Sources

Quality Considerations

Unlike many traditional supplements with centuries of historical use, krill oil is a relatively modern nutritional supplement that emerged in the late 20th and early 21st centuries. The commercial development of krill oil as a dietary supplement began in the 1990s, following scientific interest in the unique phospholipid structure of krill-derived omega-3 fatty acids and the natural presence of astaxanthin. The first patents for krill oil extraction methods were filed in the late 1990s, with commercial products becoming widely available in the early 2000s. While krill oil itself lacks traditional historical usage, its development was influenced by the well-established historical use of marine oils for health purposes across multiple cultures.

Traditional Arctic and coastal populations, including the Inuit, Norwegian, and Japanese cultures, have long consumed marine animals and their oils for nutritional and medicinal purposes. These traditional practices provided the foundation for scientific investigation into the health benefits of marine-derived omega-3 fatty acids. The specific interest in Antarctic krill as a source of omega-3 fatty acids began in the 1980s, when researchers observed that krill contained significant amounts of EPA and DHA in a phospholipid form, rather than the triglyceride form found in fish. This discovery coincided with growing scientific understanding of the importance of omega-3 fatty acids for human health, particularly cardiovascular and neurological function.

The commercial krill fishery in Antarctica began in the 1970s, primarily for use as aquaculture and animal feed, with human consumption developing later. Neptune Technologies & Bioressources (Canada) was among the first companies to develop and patent specific extraction methods for krill oil as a human dietary supplement in the late 1990s. Their product, Neptune Krill Oil (NKO), was introduced to the market in the early 2000s and was the subject of some of the earliest clinical studies on krill oil supplementation. The development of krill oil as a supplement also coincided with growing concerns about the sustainability of traditional fish oil sources and increasing consumer demand for alternatives with improved bioavailability and reduced contaminant levels.

Unlike fish oil, which had been used in traditional medicine for centuries before being developed into modern supplements, krill oil represents a more direct translation of scientific research into commercial products without a significant history of traditional use. This modern development pathway has meant that krill oil has been subject to scientific investigation from its earliest commercial availability, with studies specifically designed to evaluate its unique properties compared to other marine oils.

Ulven SM, Holven KB. Comparison of bioavailability of krill oil versus fish oil and health effect. Vascular Health and Risk Management. 2015;11:511-524. doi:10.2147/VHRM.S85165, Ursoniu S, Sahebkar A, Serban MC, et al. Lipid-modifying effects of krill oil in humans: systematic review and meta-analysis of randomized controlled trials. Nutrition Reviews. 2017;75(5):361-373. doi:10.1093/nutrit/nuw063, Cicero AF, Colletti A. Krill oil: evidence of a new source of polyunsaturated fatty acids with high bioavailability. Clinical Lipidology. 2015;10(1):1-4. doi:10.2217/clp.14.66

Effects of Krill Oil on Endothelial Function and Other Cardiovascular Risk Factors in Participants With Type 2 Diabetes (NCT02053415), Krill Oil for the Treatment of Premenstrual Syndrome (NCT01620593), Krill Oil Supplementation in Overweight Men and Women (NCT03482012), Krill Oil and Cognitive Function in Older Adults (NCT03613844), Krill Oil for the Treatment of Non-alcoholic Fatty Liver Disease (NCT04571060)