1–3 g/day. Provides less EPA+DHA per capsule than a concentrated fish oil.
Lowers triglycerides, similarly to fish oil at equal EPA+DHA.
View the study (RCT) →The phospholipid is absorbed somewhat better than the triglycerides in fish oil.
View the study (RCT) →⏱ 3 min read
Krill oil is the oil extracted from Antarctic krill (Euphausia superba), a small crustacean of the coldest waters on the planet that makes up the most abundant animal biomass in the ocean and the base of the Antarctic food chain; its lipid composition differs from that of conventional fish oil in a biochemically relevant respect: the omega-3 fatty acids (EPA and DHA) are bound predominantly to phospholipids (phosphatidylcholine) rather than to triglycerides, a structural feature with real implications for absorption and bioavailability.
In addition to its phospholipid omega-3 profile, krill oil contains astaxanthin (a carotenoid with potent antioxidant activity that gives krill and salmon their characteristic orange-pink color) and choline, two micronutrients with added nutritional value; these distinguishing characteristics have driven krill oil as a premium alternative to traditional fish oil, at a significantly higher cost per gram and with promises of superior bioavailability that clinical research has partially confirmed.
Several comparative pharmacokinetic studies have documented that the EPA and DHA in krill oil reach higher plasma concentrations than those in fish oil at the same total omega-3 dose, an advantage attributed to the better absorption of phospholipids compared with triglycerides, especially in people with suboptimal pancreatic or biliary function; the size of the difference varies across studies (between 10 and 60 percent more bioavailable) and does not necessarily translate into significant clinical differences when doses are properly matched.
In mild to moderate hypertriglyceridemia, several small trials have shown significant reductions in plasma triglycerides (between 10 and 25 percent) with doses of 1-4 grams daily of krill oil for 8-12 weeks, magnitudes comparable to those of conventional fish oil at equivalent EPA+DHA doses; the clinical usefulness is the same as that of fish oil, and there are no robust data showing clinical superiority of krill for this indication.
In chronic inflammatory conditions (arthritis, subclinical cardiovascular disease), krill oil has shown modest reductions in inflammatory markers (C-reactive protein, IL-6) and in symptoms in some small studies, with a profile similar to that of conventional fish oil; the added astaxanthin could provide additional antioxidant value, but the clinical effects attributable specifically to this difference are hard to isolate.
In premenstrual syndrome, a small randomized trial published in 2003 showed significant improvements on PMS scales and reduced use of pain relievers over 3 months with krill oil at 2 grams daily; the data are interesting but require independent replication in larger cohorts before this indication can be considered well established.
The doses studied range from 1 to 4 grams daily of krill oil, divided into one or two doses with meals; typical commercial products contain 500-1,000 mg of oil per capsule with approximately 100-180 mg of EPA+DHA per capsule; the total omega-3 content per capsule is usually lower than that of concentrated fish oil, which is why several capsules a day are needed to match therapeutic doses.
Generally well tolerated; the most common adverse effects are mild digestive discomfort (seafood-flavored burps, occasional dyspepsia), significantly less than with fish oil because of the phospholipid structure; people with shellfish allergy should avoid krill oil because of the risk of allergic reactions (krill is a crustacean); those taking anticoagulants such as warfarin should exercise theoretical caution because of an antiplatelet effect similar to that of fish oil; the cost per gram of omega-3 is clearly higher than that of conventional fish oil, an important practical consideration: for most omega-3 indications, pharmaceutical-grade purified fish oil offers a better cost-effectiveness ratio than krill, which is better justified in people with poor digestive tolerance of conventional fish oil or in those who specifically value the added astaxanthin; in pregnancy and breastfeeding, specific data are limited, although omega-3 intake is generally beneficial.
Information, not medical advice. Scientific evidence reflects the quality of the studies.