Blackmores Institute

Krill oil, derived from Antarctic krill (Euphausia superba), is a nutrient-rich source of phospholipids, long-chain omega-3 polyunsaturated fatty acids, potent antioxidants, and essential micronutrients.1 Its distinctive composition and enhanced bioavailability have attracted growing clinical interest, with research exploring potential benefits across cardiovascular, cognitive, inflammatory, menstrual, metabolic, and skin health (see Figure 1).2
<img src="https://images.contentstack.io/v3/assets/blt948bd74310fc0ad0/bltd1678eed878a2cc2/6a14f874cc1508dd91e4327c/BI-Krill-Oil-A-nutrient-dense-marine-oil-with-diverse-health-benefits-Figure1.jpg" alt="BI-Krill-Oil-A-nutrient-dense-marine-oil-with-diverse-health-benefits-Figure1.jpg" class="embedded-asset" />Figure 1. Health benefits of krill oil.2<h3> Nutritional composition of krill oil</h3>Krill oil’s health benefits are attributed to its diverse, yet synergistic nutritional components:<ul><li>Lipids: Approximately 40% of krill oil fatty acids are associated with its eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content, offering significant cardiovascular, antioxidant, and anti-inflammatory health benefits.1 Krill oil also contains choline, essential for neurotransmitter synthesis (acetylcholine), and phospholipids, which aid in lipid transport, homocysteine reduction,3 and cognitive function.4</li><li>Astaxanthin: This red-pigmented carotenoid responsible for the distinctive hue of krill oil possesses potent antioxidant properties - up to ten times stronger than zeaxanthin, lutein, and β-carotene.1 With its unique molecular structure, astaxanthin can stretch through the cell membrane bilayer, stabilising membranes and protecting against oxidative stress.5 It has been studied for potential metabolic, anti-inflammatory, immune, cognitive, cardiovascular, ocular, and skin-protective effects.5</li><li>Micronutrients: Krill oil naturally contains vitamins A and E, which contribute to antioxidant defences, immune function, and cellular integrity,1 alongside key trace minerals such as calcium, magnesium, potassium, selenium, and zinc.4</li><li>Flavonoids: Krill oil features flavonoids, plant-derived polyphenols with antioxidant, antimicrobial, and anti-inflammatory properties, further enhancing its therapeutic potential.4</li></ul><h3> Bioavailability: the phospholipid advantage</h3>A distinctive feature of krill oil is the phospholipid structure of its omega-3 fatty acids. While fish oil delivers EPA and DHA predominantly in triglyceride form,4 krill oil provides 60-70% of its omega-3s bound to phospholipids, primarily phosphatidylcholine.6Phospholipids are vital components of cell membranes, supporting membrane integrity and function. When omega-3s are delivered in this form, they readily integrate into cell membranes, promoting bioavailability.7A recent meta-analysis of 26 studies assessing omega-3 bioavailability markers, including the Omega-3 Index (O3i) and area under the curve (AUC) for EPA and DHA, reported favourable absorption profiles for krill oil at lower doses (under 2000 mg/day), with phospholipid forms demonstrating superior uptake compared to triglyceride sources.7<h3> Clinical evidence for health benefits</h3>A growing body of clinical research has investigated krill oil’s therapeutic potential across multiple health domains:<table><tbody><tr><th>Health area</th><th>Evidence summary</th></tr><tr><td>Cardiovascular health</td><td>A 2023 systematic review and meta-analysis of randomised controlled trials reported that krill oil supplementation lowers total cholesterol, LDL-cholesterol, and triglycerides - key contributors to cardiovascular disease risk.8</td></tr><tr><td>Cognitive health</td><td>Evidence indicates that phospholipids improve cognition across the lifespan, including attention, learning, and memory.9 Omega-3 fatty acids improve cognitive outcomes via mechanisms including increased brain acetylcholine levels, anti-inflammatory actions, enhanced neuroplasticity, and synaptic vesicle density.10 Astaxanthin has demonstrated neuroprotective effects, enhancing memory, reaction time, and attention.11</td></tr><tr><td>Exercise and performance</td><td>A double-blind, placebo-controlled trial found that 3 g/day krill oil increased lean body mass by approximately 2.2% over two months of resistance training.1</td></tr><tr><td>Joint and inflammatory health</td><td>A randomised controlled trial (RCT) in adults with mild to moderate knee osteoarthritis found that 4 g/day krill oil improved pain, stiffness, and function scores compared to placebo.12 Reductions in C-reactive protein (CRP), a marker of systemic inflammation, have also been documented at a dose of 500 mg twice daily.13</td></tr><tr><td>Menstrual health</td><td>A double-blind, randomised clinical trial found that 1 g/day krill oil over three months alleviated dysmenorrhea and improved both emotional and physical symptoms associated with premenstrual syndrome.1</td></tr><tr><td>Metabolic and microbiome health</td><td>Omega-3 fatty acids support metabolic health and positively influence the gut microbiome.14 In models of obesity and metabolic dysfunction, krill oil improved insulin sensitivity, lipid profiles, and increased the abundance of beneficial gut bacteria such as Bacteroides and Lactobacillus species, and short-chain fatty acid producers.4</td></tr><tr><td>Muscle mass and strength preservation alongside weight loss</td><td>A randomised trial found that krill oil supplementation during weight loss attenuated the reduction in fat-free mass and muscle strength, improved functional performance, and reduced inflammatory markers supporting its role in weight loss.15</td></tr><tr><td>Skin health</td><td>Krill oil has demonstrated skin-protective effects, including anti-ageing, anti-inflammatory, and wound healing actions. It reduces wrinkles, trans-epidermal water loss, collagen degradation, and skin oedema, while relieving inflammatory skin conditions like atopic dermatitis and psoriasis by strengthening the skin barrier.2</td></tr></tbody></table><h3> Conclusion</h3>Krill oil offers a distinctive combination of highly bioavailable omega-3 fatty acids, phospholipids, astaxanthin, flavonoids, and essential micronutrients. Whilst considered safe and well tolerated,8 it’s not suitable for those with seafood or shellfish allergies,16 and for some, minor gastrointestinal symptoms may occasionally occur at higher doses,8 and <a href="/interactions/omega-3" target="_self" style="">those taking medications should ensure interactions are reviewed prior to supplementing with krill oil</a>. Current evidence highlights the potential of krill oil across a range of health conditions, with ongoing research set to further clarify and expand our understanding of this nutrient-dense marine oil’s therapeutic applications.<h3> References</h3><ol><li>Shahidi F, Abad A. Why is Antactic krill (Euphasia superba) oil on the spotlight? A review. Food Production Processing and Nutrition. 2024 Sep 11;6(1).</li><li>Duo L, Yang J, Wang X, Zhang G, Zhao J, Zou H, et al. Krill oil: nutraceutical potential in skin health and disease. Frontiers in Nutrition. 2024 Jul 12;11.</li><li>National Institute of Health. Office of Dietary Supplements - Choline. Available from: https://ods.od.nih.gov/factsheets/Choline-HealthProfessional</li><li>Colletti A, Cravotto G, Citi V, Martelli A, Testai L, Cicero AFG. Advances in Technologies for Highly Active Omega-3 Fatty Acids from Krill Oil: Clinical Applications. Marine Drugs. 2021 May 26;19(6):306.</li><li>Sztretye M, Dienes B, Gönczi M, Czirják T, Csernoch L, Dux L, et al. Astaxanthin: A Potential Mitochondrial-Targeted Antioxidant Treatment in Diseases and with Aging. Oxidative Medicine and Cellular Longevity. 2019 Nov 11;2019:1–14.</li><li>Ramprasath VR, Eyal I, Zchut S, Shafat I, Jones PJH. Supplementation of krill oil with high phospholipid content increases sum of EPA and DHA in erythrocytes compared with low phospholipid krill oil. Lipids in Health and Disease. 2015 Nov 4;14(1). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4632328/</li><li>Pham TPT, Hoang TV, Cao PTN, Le TTD, Ho VTN, Vu TMH, et al. Comparison of Omega-3 polyunsaturated fatty acids bioavailability in fish oil and krill oil: Network Meta-analyses. Food Chemistry X. 2024 Oct 5;24:101880–0.</li><li>Huang H, Liao D, He B, Zhou G, Cui Y. Clinical effectiveness of krill oil supplementation on cardiovascular health in humans: An updated systematic review and meta-analysis of randomized controlled trials. Diabetes &amp; Metabolic Syndrome: Clinical Research &amp; Reviews. 2023 Dec 1;17(12):102909. Available from:https://www.sciencedirect.com/science/article/abs/pii/S187140212300205</li><li>Schverer M, O’Mahony SM, O’Riordan KJ, Donoso F, Roy BL, Stanton C, et al. Dietary phospholipids: Role in cognitive processes across the lifespan. Neuroscience &amp; Biobehavioral Reviews. 2020 Apr;111:183–93.</li><li>Burri L. Krill Oil Supplementation and Cognitive Function. Diet and Nutrition in Dementia and Cognitive Decline. 2015 [cited 2025 Jul 10];1031–8. Available from: https://www.researchgate.net/publication/285531761_Krill_Oil_Supplementation_and_Cognitive_Function</li><li>Joshua J, Sparks SA, Marchant DC, McNaughton LR. The Effects of Astaxanthin on Cognitive Function and Neurodegeneration in Humans: A Critical Review. Nutrients. 2024 Mar 14;16(6):826–6.</li><li>Stonehouse W, Benassi-Evans B, Bednarz J, Vincent AD, Hall S, Hill CL. Krill oil improved osteoarthritic knee pain in adults with mild to moderate knee osteoarthritis: a 6-month multicenter, randomized, double-blind, placebo-controlled trial. The American Journal of Clinical Nutrition. 2022 Jul 26.</li><li>Cicero AFG, Rosticci M, Morbini M, Cagnati M, Grandi E, Parini A, et al. Lipid-lowering and anti-inflammatory effects of omega 3 ethyl esters and krill oil: a randomized, cross-over, clinical trial. Archives of Medical Science. 2016;3:507–12.</li><li>Fu Y, Wang Y, Gao H, Li D, Jiang R, Ge L, et al. Associations among Dietary Omega-3 Polyunsaturated Fatty Acids, the Gut Microbiota, and Intestinal Immunity. Wu M, editor. Mediators of Inflammation. 2021 Jan 2;2021:1–11. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7801035/</li><li>Mansour Alblaji, Gray SR, Taibah Almesbehi, Morrison DJ, Malkova D. Benefits of Krill Oil Supplementation During Alternate-Day Fasting in Adults With Overweight and Obesity: A Randomized Trial. PubMed. 2025 Jul 16</li><li>Albert BB, Derraik JG, Brennan CM, Biggs JB, Garg ML, Cameron-Smith D, et al. Supplementation with a blend of krill and salmon oil is associated with increased metabolic risk in overweight men. The American Journal of Clinical Nutrition. 2015 May 27;102(1):49–57.</li></ol>

<h3>Key highlights:</h3><ul><li>Krill oil is rich in highly bioavailable phospholipid-bound EPA and DHA.</li><li>Contains astaxanthin, a potent antioxidant providing cellular protection.</li><li>Delivers essential micronutrients including vitamins A, E, and minerals.</li><li>Clinically supported benefits for cardiovascular, inflammatory, cognitive, menstrual, metabolic, and skin health.</li><li>Generally safe and well-tolerated. </li></ul>Read on to learn about how krill oil’s unique composition and bioavailability translate into clinically beneficial health outcomes.

Key highlights:

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