Krill oil

Q: What is krill oil?

It is an oil made from Antarctic krill, tiny crustaceans. It supplies the marine omega-3 fats EPA and DHA, mostly as phospholipids, according to NCCIH.

Q: Is krill oil better absorbed than fish oil?

The studies disagree. A 4-week trial with matched EPA and DHA found no real difference, a 12-week trial found about a 1.5-fold bigger rise with krill oil, and a pooled analysis leaned towards krill oil with high differences between studies. These are blood levels, not health results.

Q: Does krill oil lower cholesterol or triglycerides?

Pooled trials found lower triglycerides, about as much as fish oil. Results on LDL and HDL cholesterol conflict between reviews. These are lab markers, not fewer heart attacks.

Q: Does krill oil help the heart?

Not shown. No krill oil trial of heart attacks or strokes was read. A Cochrane review of mostly fish oil trials found little or no effect on death, heart events or stroke, with a possible slight fall in coronary heart disease events (low certainty).

Q: Does krill oil help knee pain?

Mixed. The largest independent trial (JAMA 2024, 262 people) found no pain benefit over placebo. A smaller 2022 trial found a modest gain, and pooled analyses disagree. Ask your doctor about arthritis care.

Q: Does krill oil help depression?

Evidence is thin. One small trial of 50 adults found lower depression scores with krill oil than placebo; a year-long trial in healthy teenagers found no effect. NCCIH says it is uncertain whether omega-3 supplements help depression. Depression needs medical care.

Q: Which foods have EPA and DHA?

Fatty fish have the most. By USDA data, 3 oz of cooked farmed salmon has about 1.24 g DHA and 0.59 g EPA, and herring about 0.94 g and 0.77 g. Canned light tuna and shrimp have much less.

Q: Can people with a shellfish allergy use krill oil?

Ask an allergist first. Krill are crustaceans, and a shellfish allergen protein was tentatively found in krill oil products in a 2013 laboratory test. No study of allergic reactions to krill oil was read.

Q: Does krill oil interact with blood thinners?

It may. A prescription EPA fish-oil label warns of more bleeding with aspirin, clopidogrel or warfarin. No krill oil study was read, so this is by analogy. Ask your doctor or pharmacist.

Q: Can omega-3 supplements affect the heart rhythm?

In a 2021 meta-analysis of large trials of marine omega-3 supplements, atrial fibrillation was more common (HR 1.25), and more so above 1 g a day. Krill oil was not tested separately. A bigger Cochrane review found no difference in arrhythmia overall (low certainty).

Euphausia superba (oil) · also called Antarctic krill oil, aceite de kril

Krill oil is a supplement made from tiny Antarctic crustaceans. It supplies the marine omega-3 fats EPA and DHA, mostly as phospholipids. Trials show it raises blood omega-3 and lowers triglycerides about as fish oil does, but the largest knee-pain trial found no benefit and no krill oil heart-attack trial was found. Ask a doctor or pharmacist first if you take blood thinners, have a shellfish allergy or have heart rhythm problems.

General information, not medical advice. Last substantive update October 26, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

Get your Krill oil today. Order now from Amazon and have it delivered to your door.Shop Krill oil on AmazonSupport our free guides: as an Amazon Associate we earn from qualifying purchases.

About Krill oil

Krill oil is a marine omega-3 supplement made from tiny Antarctic crustaceans. It reliably raises blood EPA and DHA and lowers triglycerides, but it has not been shown to prevent heart disease, and the best knee-pain trial found no benefit.

What krill oil is

Krill oil is an oil taken from Antarctic krill (Euphausia superba), a small marine crustacean. NCCIH says it contains omega-3 fats in the form of phospholipids. The two omega-3s that research focuses on are EPA and DHA. Fish oil, cod liver oil and algal oil are other supplement sources; each has its own page.

Some krill oil products also contain the red pigment astaxanthin; the oil used in one knee trial had 0.45 g astaxanthin in 4 g of oil.

^{23 22 16}

Where EPA and DHA come from in food

Fatty fish are the richest food sources. By USDA data, 3 oz (85 g) of cooked farmed Atlantic salmon has about 1.24 g DHA and 0.59 g EPA, Atlantic herring about 0.94 g DHA and 0.77 g EPA, Atlantic mackerel about 0.59 g DHA and 0.43 g EPA, canned light tuna in water about 0.17 g DHA and 0.02 g EPA, and cooked shrimp about 0.12 g DHA and 0.11 g EPA. Krill oil itself is not in the database.

NCCIH says that for some conditions the evidence for seafood is stronger than for omega-3 supplements. The US Dietary Guidelines for Americans 2020-2025 advise adults to eat 8 ounces or more of a variety of seafood a week.

^{25 23}

Is it absorbed better than fish oil?

Krill oil carries its omega-3 mostly as phospholipids, while most fish oil carries it as triglycerides or ethyl esters. The studies disagree about whether that matters. A 2015 trial of 66 healthy adults, run mostly by an omega-3 company, found similar blood levels when the EPA and DHA were matched. A 2026 trial of 72 healthy adults found krill oil raised EPA and DHA about 1.5 times more than fish oil. A 2024 pooled analysis leaned towards krill oil at lower amounts but warned of high differences between studies.

These are blood levels in healthy people. They do not show better health results.

^{20 11 14}

What the research shows

Krill oil lowers triglycerides in the short term, about as fish oil does, and the reviews disagree on cholesterol. No trial of heart attacks or strokes with krill oil was read. For knee osteoarthritis, a large 2024 trial found no pain benefit, though an earlier smaller trial found a small one. Evidence for depression is very thin, and nothing krill-specific was read for memory or the eyes.

Almost all results are from short trials in adults, and several were paid for or run by krill oil companies.

^{18 7 9 10 16 2 13 3}

Seafood versus capsules

Eating seafood gives omega-3 together with protein, vitamins and minerals. No trial compared krill oil with eating fish. This page gives no amounts to take; if you wonder about your own needs, ask a doctor, pharmacist or dietitian.

²³

At a glance

Traditional uses history, not proof

A modern marine oil supplement; no long traditional use as a medicine was found

Studied for research

Raising blood EPA and DHA, mixed certainty
Seafood sources of EPA and DHA, high certainty
Blood triglycerides, moderate certainty
LDL and HDL cholesterol, low certainty
Very high triglycerides (purpose-made extract), low certainty
Knee osteoarthritis pain, mixed certainty
Heart attacks and strokes, insufficient evidence
Mood and depression, insufficient evidence
Omega-3 in breast milk, very-low certainty

Main compounds

EPA (eicosapentaenoic acid)
DHA (docosahexaenoic acid)
Phospholipid-bound omega-3
Astaxanthin (in some products)

Common forms

Softgel capsules and oils
Some products also contain astaxanthin

Research links: 2017 meta-analysis: krill oil and blood fats (7 trials) · 2020 network meta-analysis: krill oil versus fish oil (64 trials) · 2024 JAMA trial: krill oil for knee osteoarthritis · 2026 trial: krill oil versus fish oil, blood omega-3 · 2021 meta-analysis: marine omega-3 and atrial fibrillation · Research Library · Genes & Biomarkers Library

What it is and its history

Accepted scientific name: Euphausia superba (Antarctic krill); krill oil is the oil extracted from it
Naming authority: Dana, 1850
Common names: Krill oil (English); Antarctic krill oil (English); Aceite de kril (Spanish)
Family or group: Krill are small marine crustaceans (family Euphausiidae). Krill oil is a marine omega-3 supplement; NCCIH says it contains omega-3s in the form of phospholipids.
Classification: Animalia > Arthropoda > Malacostraca > Euphausiacea > Euphausiidae > Euphausia > Euphausia superba
Native range: The name "Antarctic krill" points to the Southern Ocean; the range was not looked up in a source.
Habitat: Not looked up.
Harvest and processing: Not researched.
Look-alikes and adulterants: Name: Fish oil; Note: Carries EPA and DHA mostly as triglycerides or ethyl esters. Has its own page.; Name: Cod liver oil; Note: A fish liver oil that also contains vitamins A and D (NCCIH). Has its own page.; Name: Algal oil; Note: A vegetarian source of DHA, sometimes with EPA (NCCIH). Has its own page.; Name: Calanus oil; Note: Oil from another small marine animal (a copepod). One 12-week trial compared Calanus, fish and krill oil; it was not read in full here.
Sustainability and conservation: Not assessed.

What is inside, and how it may work

What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.

Main compounds

Compound	Family	Where it is concentrated	Activity studied	Level of evidence
Eicosapentaenoic acid (EPA) PubChem 5282847	omega-3 fatty acid	Oil from Euphausia superba, mostly in phospholipids 0.60 g in 4 g of the krill oil tested in the 2022 knee trial (product-specific).	Marine omega-3 fat; raises blood and red blood cell EPA when taken. Named by NCCIH as one of the two main studied omega-3s. ^{16 23 11}	Human data
Docosahexaenoic acid (DHA) PubChem 445580	omega-3 fatty acid	Oil from Euphausia superba, mostly in phospholipids 0.28 g in 4 g of the krill oil tested in the 2022 knee trial (product-specific).	Marine omega-3 fat; found in the brain and eye. PubChem lists it as doconexent. ^{16 23 11}	Human data
Astaxanthin PubChem 5281224	carotenoid pigment	Some krill oil products 0.45 g in 4 g of the krill oil tested in the 2022 knee trial (product-specific).	Red pigment present in the krill oil used in that trial. No separate effect of astaxanthin was tested. ¹⁶	Human data
Phospholipid-bound omega-3	phospholipid	Krill oil Not read from a source.	NCCIH says krill oil contains omega-3s in the form of phospholipids. Whether this makes it better absorbed than fish oil is mixed (see Benefits). ^{23 20 11}	Human data

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Raising blood EPA and DHA	Not specified in the sources read	Krill oil raises plasma and red blood cell EPA and DHA in people. Whether the phospholipid form raises them more than fish oil is disputed: no difference in one 4-week trial, about 1.5-fold more in a 12-week trial. ^{20 11 14}	Human data
Lowering blood triglycerides	Not specified in the sources read	The drop in triglycerides depends on how much omega-3 is taken; in the 2020 analysis 1 g of omega-3 from krill oil lowered median triglycerides by 9.8 mg/dL and from fish oil by 9.0 mg/dL. ⁹	Human data
Knee pain and joint inflammation	Not specified	A trial team describes krill oil as "rich in anti-inflammatory" omega-3s, but the knee trials did not show the mechanism and the largest trial found no pain benefit. ^{16 10}	Proposed, not shown

Absorption, metabolism and elimination

Absorption: Plasma EPA plus DHA after 4 weeks was similar for krill oil and two fish oil forms when matched (within 24%). A 12-week trial found a roughly 1.5-fold larger rise with krill oil. A network meta-analysis reported better absorption at lower amounts. Studies disagree.
Distribution: Red blood cell omega-3 (omega-3 index) rose from 6.0% to 8.9% with krill oil in the 2022 trial.
Metabolism: Not read.
Elimination: Not read.
Bioavailability: Mixed, as above. Women had a larger EPA rise than men in the 2026 trial; APOE4 carriers and non-carriers responded alike.

^{20 11 14 16}

Isolated compounds versus whole extracts

Seafood and supplements are not the same. NCCIH says that for some health conditions the evidence for eating seafood is stronger than for omega-3 supplements, because seafood has other nutrients and because people who eat seafood tend to have healthier lifestyles. Krill oil is an extract, and no study compared it with eating fish.

Nutritional composition

USDA FoodData Central SR Legacy (April 2018 release), read 2026-10-26 from a saved local copy: per 3 oz (85 g) cooked, farmed Atlantic salmon has about 1.24 g DHA and 0.59 g EPA; wild Atlantic salmon about 1.21 g DHA and 0.35 g EPA; Atlantic herring about 0.94 g DHA and 0.77 g EPA; Atlantic mackerel about 0.59 g DHA and 0.43 g EPA; canned light tuna in water about 0.17 g DHA and 0.02 g EPA; cooked shrimp about 0.12 g DHA and 0.11 g EPA. Krill oil is not in this database. These are food facts, not advice.

10benefits and uses looked at

26studies and sources checked

High certaintybest evidence rating found

7lab markers tracked in trials

1 high certainty1 moderate certainty2 mixed findings2 low certainty1 very low certainty3 not enough evidence

What was looked at

The 10 benefits and uses checked for Krill oil, each with how strong the evidence is. Tap one to open it.

Raising EPA and DHA in the bloodMixed findings
Omega-3 EPA and DHA from seafoodHigh certainty
Blood triglyceridesModerate certainty
LDL and HDL cholesterolLow certainty
Very high triglycerides (a purpose-made krill extract)Low certainty
Heart attacks, strokes and deathNot enough evidence
Knee osteoarthritis painMixed findings
Mood and depressionNot enough evidence
Omega-3 in breast milkVery low certainty
Memory, eyes, skin and other usesNot enough evidence

Lab markers tracked in the studies

Blood EPA and DHATriglyceridesLDL cholesterolHDL cholesterolOmega-3 index (red blood cell EPA plus DHA)Knee pain scoreHamilton Depression Rating Scale score

What is Krill oil good for?

The main studied uses and how strong the human evidence is for each. Most results are from short trials in adults, and several were run or paid for by krill oil companies.

Raising EPA and DHA in the bloodMixed findingsKrill oil raises blood EPA and DHA. Whether it does so better than fish oil is disputed: no difference in a 4-week trial of 66 adults, about 1.5 times the rise in a 12-week trial of 72 adults, and a pooled analysis leaning towards krill oil with high differences between studies. Omega-3 EPA and DHA from seafoodHigh certaintyBy USDA data, 3 oz (85 g) of cooked farmed Atlantic salmon has about 1.24 g DHA and 0.59 g EPA, herring about 0.94 g and 0.77 g, mackerel about 0.59 g and 0.43 g, and canned light tuna in water about 0.17 g and 0.02 g. Krill oil is not in the database. Blood triglyceridesModerate certaintyPooled trials found lower triglycerides with krill oil (about 14 mg/dL lower in a 2017 review of 662 people). A 2020 comparison found no significant difference from fish oil, and the drop depends on how much omega-3 is taken. This is a lab marker, not fewer heart attacks. LDL and HDL cholesterolLow certaintyOne review found lower LDL and higher HDL with krill oil, but the comparison with fish oil found no clear difference. NCCIH says omega-3s lower triglycerides but not other blood fats. The reviews conflict. Very high triglycerides (a purpose-made krill extract)Low certaintyTwo pooled sponsor-run trials of 520 people with triglycerides of 500 to 1,500 mg/dL found a krill-derived agent lowered triglycerides about 11 percentage points more than placebo. It is a specialised product, not an ordinary supplement. Heart attacks, strokes and deathNot enough evidenceNo krill oil trial of heart attacks or strokes was read. A Cochrane review of 86 mostly fish oil trials found little or no effect on death, heart events or stroke, with a possible slight fall in coronary heart disease events (low certainty). Knee osteoarthritis painMixed findingsThe largest independent trial (262 people, JAMA 2024) found no pain benefit over placebo. An earlier trial of 235 people found a small extra gain in pain, stiffness and function. Two meta-analyses disagree. Mood and depressionNot enough evidenceOne very small trial in adults with depression found lower scores with krill oil than placebo over 8 weeks; a year-long trial in healthy teenagers found no effect. NCCIH says it is uncertain whether omega-3s help depression. Omega-3 in breast milkVery low certaintyIn a 16-woman pilot, krill oil raised DHA and EPA in breast milk over 30 days. No baby outcome was measured. Memory, eyes and other usesNot enough evidenceNo krill oil trial was read. For omega-3 supplements in general, NCCIH reports no benefit over placebo for dry eye in a large trial and no extra benefit when EPA and DHA were added to the AREDS2 eye vitamins.

Benefits, one by one

Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.

Raising EPA and DHA in the blood

Mixed findings

Krill oil raises the blood levels of the marine omega-3 fats EPA and DHA. The open question is whether it does so better than fish oil. Three studies disagree: one found no difference when the EPA and DHA amounts were matched, a newer one found krill oil raised levels about 1.5 times more, and a pooled analysis leaned towards krill oil at lower amounts.

4 studiesKrill oil capsules, omega-3 mostly as phospholipids, compared with fi…

Studies, doses and limits

What the trials found

In 66 healthy adults given matched amounts of EPA plus DHA for 4 weeks, plasma and red blood cell levels did not differ significantly between krill oil and two fish oil forms (krill 118.5 versus 108 and 90.9 micrograms per mL; p = 0.052); most authors work for an omega-3 company. In 72 healthy adults given about 1.1 g a day of omega-3 for 12 weeks, krill oil raised plasma EPA and DHA about 1.5-fold more than fish oil, in men and women, with or without the APOE4 gene. A 2024 network meta-analysis of 26 studies reported better absorption from krill oil, especially under 2,000 mg, but flagged high differences between studies. NCCIH describes krill oil as omega-3 in phospholipid form.

Results

Krill oil reliably raises blood EPA and DHA. Whether it raises them more than fish oil is mixed: two studies and one pooled analysis point to a bigger rise, one industry-linked trial found no real difference.

Effect sizes as reported

Krill versus fish oil, 4 weeks: no significant difference (p = 0.052). 12 weeks: about 1.5-fold greater rise in EPA and DHA with krill oil. Network meta-analysis: pooled figures not in the abstract.

Why this rating

Mixed. All studies agree the levels rise. They disagree on krill oil versus fish oil, and the studies differ in design, length and who paid.

Form and dose studied

Krill oil capsules, omega-3 mostly as phospholipids, compared with fish oil triglycerides or ethyl esters in healthy adults.

Who was studied

Healthy adults.

Limits

Healthy people only. Blood levels are not a health result. Doses were matched differently in each study. Two of the studies are small.

Why researchers looked

Krill oil carries its omega-3 mostly in phospholipids, while most fish oil carries it as triglycerides or ethyl esters. People wonder whether the phospholipid form is absorbed better.

Traditional use

Krill oil is a supplement made from small Antarctic crustaceans. It has no long traditional use as a medicine; what is known comes from modern trials, and a normal job for omega-3 fats in the body is not proof that a pill adds benefit.

Proposed mechanism Human biomarker

EPA and DHA from the oil enter the blood and red blood cells. Whether the phospholipid form is taken up better is the question these studies test. This is a measured blood response, not a health effect.

A proposed mechanism does not show that the effect happens in people.

See the Safety tab for bleeding, allergy and heart rhythm cautions.

^{20 11 14 23}

Omega-3 EPA and DHA from seafood

High certainty

The same marine omega-3 fats come from seafood. By USDA data, 3 oz (85 g) of cooked farmed Atlantic salmon has about 1.24 g DHA and 0.59 g EPA, Atlantic herring about 0.94 g DHA and 0.77 g EPA, Atlantic mackerel about 0.59 g DHA and 0.43 g EPA, and canned light tuna in water about 0.17 g DHA and 0.02 g EPA. Krill oil is not in this database.

2 studiesFoods only. This is not a recommendation to eat any food or to take k…

Studies, doses and limits

What the trials found

No trial was read that compares krill oil with eating fish. NCCIH says EPA and DHA are found in seafood, especially cold-water fish such as salmon, mackerel and tuna, and in shellfish; the US Dietary Guidelines for Americans 2020-2025 advise adults to eat 8 ounces or more of a variety of seafood a week. NCCIH also says that for some conditions the evidence for seafood is stronger than for omega-3 supplements, partly because seafood brings other nutrients and because people who eat seafood tend to have healthier lifestyles. Other plant omega-3 (ALA) comes from flaxseed, soybean and canola oils, chia seeds and walnuts, but it is a different fat.

Results

Fatty fish carry far more EPA and DHA per portion than the lean fish and shellfish listed. Seafood evidence is separate from supplement evidence.

Effect sizes as reported

USDA per 3 oz (85 g) cooked: farmed salmon DHA 1.24 g, EPA 0.59 g; wild salmon DHA 1.21 g, EPA 0.35 g; herring DHA 0.94 g, EPA 0.77 g; mackerel DHA 0.59 g, EPA 0.43 g; light tuna in water DHA 0.17 g, EPA 0.02 g; shrimp DHA 0.12 g, EPA 0.11 g.

Why this rating

High that foods contain these amounts (USDA tables, 2018 release). It does not tell you how well you absorb them or what you need.

Form and dose studied

Foods only. This is not a recommendation to eat any food or to take krill oil.

Who was studied

General adult diet.

Limits

SR Legacy values come from a 2018 release; cooking, species and farming change the amounts. Mercury in fish was not researched here.

Why researchers looked

Many people ask how a krill oil capsule compares with simply eating fish.

Traditional use

Proposed mechanism Nutrient database

These are nutrient amounts in foods taken from USDA tables.

A proposed mechanism does not show that the effect happens in people.

People with a fish or shellfish allergy need to avoid those foods; see the Safety tab.

^{25 23}

Blood triglycerides

Moderate certainty

In pooled trials of krill oil, blood triglycerides fell by about 14 mg/dL (2017 review) and a later analysis again found lower triglycerides. A large comparison found krill oil and fish oil did not differ, and the drop depended on how much omega-3 people took. A fall in blood fat is a lab result, not fewer heart attacks.

5 studiesKrill oil capsules; amounts varied and are in the studies table.

Studies, doses and limits

What the trials found

A 2017 meta-analysis of 7 trials (662 people) found triglycerides 14.03 mg/dL lower with krill oil (95% CI -21.38 to -6.67). A 2023 meta-analysis of 14 trials (1,458 people) also found lower triglycerides (p = 0.0005), mainly in trials shorter than 8 weeks. A 2020 network meta-analysis of 64 trials found krill oil lowered triglycerides compared with control (-23.26 mg/dL) with no significant difference from fish oil (-4.07, CI -15.22 to 7.08). In a 12-week trial of 300 adults with borderline-high or high triglycerides, pooled krill oil groups had triglycerides 10.2% lower than placebo; the authors work for a krill oil company. NCCIH says EPA and DHA lower triglycerides by about 15 percent.

Results

Krill oil lowers triglycerides in the short term, about as fish oil does. Effects were mostly seen in short trials, and none tested heart attacks.

Effect sizes as reported

Triglycerides -14.03 mg/dL (2017); lower with p = 0.0005 (2023); -23.26 mg/dL versus control, no difference from fish oil (2020); 10.2% lower than placebo in one industry-linked trial.

Why this rating

Moderate: four sources agree on a fall in triglycerides. The authors of these reviews did not give a formal certainty grade in the abstracts, so this rating is ours; most trials were small and short.

Form and dose studied

Krill oil capsules; amounts varied and are in the studies table.

Who was studied

Adults, from healthy to borderline-high triglycerides.

Limits

Short trials; many were small; one is industry-linked. The benefit seen was in a lab marker, not in outcomes.

Why researchers looked

High triglycerides raise heart risk, and marine omega-3 fats are known to lower them.

Traditional use

Proposed mechanism Human biomarker

Marine omega-3 fats change how the liver handles blood fats. The 2020 analysis found the size of the drop depends on how much omega-3 was taken.

A proposed mechanism does not show that the effect happens in people.

Atrial fibrillation and bleeding cautions apply to marine omega-3 supplements as a group; see the Safety tab.

^{18 7 9 3 23}

LDL and HDL cholesterol

Low certainty

The pooled results on cholesterol are not consistent. A 2017 review found lower LDL ("bad") cholesterol and higher HDL ("good") cholesterol with krill oil. A 2023 review also found lower LDL and total cholesterol. But the 2020 comparison with fish oil found no clear difference, and NCCIH says EPA and DHA lower triglycerides but do not affect other blood fats.

5 studiesKrill oil capsules in trials of varied amounts.

Studies, doses and limits

What the trials found

The 2017 meta-analysis (7 trials, 662 people) found LDL cholesterol 15.52 mg/dL lower (CI -28.43 to -2.61) and HDL 6.65 mg/dL higher (CI 2.30 to 10.99); total cholesterol did not change significantly. The 2023 meta-analysis (14 trials, 1,458 people) found lower total cholesterol (p = 0.01) and LDL (p = 0.006). The 2020 network meta-analysis found krill oil and fish oil did not differ on LDL (+3.01 mg/dL, CI -5.49 to 11.51), HDL or total cholesterol. In the 12-week trial of 300 adults with higher triglycerides, LDL did not rise with krill oil. NCCIH, reviewing omega-3s in general, says they reduce triglycerides but do not affect other lipids.

Results

Mixed and low-certainty. Some pooled trials show lower LDL and higher HDL, but the findings are not steady across reviews and may be no different from fish oil.

Effect sizes as reported

LDL -15.52 mg/dL and HDL +6.65 mg/dL (2017); LDL p = 0.006 (2023); krill vs fish oil LDL +3.01 mg/dL, not significant (2020).

Why this rating

Low: the reviews conflict, the trials were small and short, and the changes are lab markers.

Form and dose studied

Krill oil capsules in trials of varied amounts.

Who was studied

Adults, mostly without heart disease.

Limits

Conflicting reviews; small, short trials; no event outcomes.

Why researchers looked

Some earlier work suggested krill oil might lower LDL cholesterol, unlike most fish oil, so researchers checked.

Traditional use

Proposed mechanism Not established

Not established. The reviews describe results and do not prove how krill oil would change LDL or HDL.

A proposed mechanism does not show that the effect happens in people.

No new safety concerns in these studies beyond those on the Safety tab.

^{18 7 9 3 23}

Very high triglycerides (a purpose-made krill extract)

Low certainty

In people with severely high triglycerides (500 to 1,500 mg/dL), a purpose-made krill-derived omega-3 agent lowered triglycerides by about 11 percentage points more than placebo. This is a drug-development product tested in two company-sponsored trials. It is not the same as ordinary krill oil capsules, and nothing here is advice to treat high triglycerides with a supplement.

1 studiesA purpose-made krill-derived omega-3 phospholipid and free fatty acid…

Studies, doses and limits

What the trials found

Two identical placebo-controlled trials were pooled (520 people, 26 weeks, product called CaPre, 4 g a day). Triglycerides fell 26.0% on the krill agent and 15.1% on placebo at 12 weeks, a difference of -10.9% (CI -20.4 to -1.5; p = 0.02), persisting at 26 weeks (-12.7%). LDL, HDL and VLDL cholesterol did not differ at 12 weeks. Safety was similar to placebo. The trial was sponsored by Acasti Pharma, and several authors have company ties or hold shares or a patent.

Results

A modest triglyceride drop in a very high-risk group, from a sponsored trial of a specialised product. It does not show what supplements on the shelf do.

Effect sizes as reported

Treatment difference -10.9% at 12 weeks (CI -20.4 to -1.5) and -12.7% at 26 weeks (CI -23.1 to -2.4).

Why this rating

Low: one pooled sponsor-run programme, a specialised agent, a moderate effect, and a placebo group that also improved by 15 percent.

Form and dose studied

A purpose-made krill-derived omega-3 phospholipid and free fatty acid product, not a typical supplement.

Who was studied

Adults with fasting triglycerides 500 to 1,500 mg/dL.

Limits

Industry sponsored; not a supplement product; blood marker only.

Why researchers looked

Prescription omega-3 products are used for very high triglycerides, so a krill-based version was tested.

Traditional use

Proposed mechanism Human biomarker

The product carries EPA and DHA as phospholipids and free fatty acids. No mechanism was tested beyond triglyceride change.

A proposed mechanism does not show that the effect happens in people.

People with very high triglycerides need medical care. Ask your doctor before using any supplement.

¹³

Heart attacks, strokes and death

Not enough evidence

No trial of krill oil has been read that counted heart attacks, strokes or deaths. The large heart trials tested fish oil or purified EPA. The best summary of omega-3 capsules as a group (mostly fish oil) found little or no effect on death, heart events or stroke, and a possible slight fall in coronary heart disease events (low certainty).

3 studiesKrill oil (no event data); fish oil capsules in the Cochrane review.

Studies, doses and limits

What the trials found

The 2023 meta-analysis (14 trials, 1,458 people) found no effect of krill oil on blood pressure, blood sugar, body composition or inflammation markers, and no event outcomes were pooled. A 2020 Cochrane review of 86 omega-3 trials (162,796 people, mostly fish oil capsules, at least 12 months) found little or no effect on all-cause death (RR 0.97), cardiovascular events (RR 0.96) or stroke (RR 1.02), and possibly a slight fall in coronary heart disease events (RR 0.91, low certainty). NCCIH describes some evidence of benefit in people with heart disease or high triglycerides.

Results

Not shown for krill oil. For omega-3 capsules as a group the picture is mostly "little or no effect", with a small possible benefit for coronary events.

Effect sizes as reported

Cochrane: cardiovascular events RR 0.96 (0.92 to 1.01); coronary heart disease events RR 0.91 (0.85 to 0.97, low certainty).

Why this rating

Insufficient for krill oil: no event trials. The Cochrane figures are for omega-3 capsules, almost all fish oil.

Form and dose studied

Krill oil (no event data); fish oil capsules in the Cochrane review.

Who was studied

Adults; Cochrane review covered varied heart risk.

Limits

Fish-oil results cannot be assumed to apply to krill oil. Blood-fat changes are not the same as fewer heart attacks.

Why researchers looked

People take krill oil for the heart, so the question is whether it prevents heart disease, not only whether it changes blood fats.

Traditional use

Proposed mechanism Not established

Not established for krill oil.

A proposed mechanism does not show that the effect happens in people.

Marine omega-3 supplements were linked to more atrial fibrillation; see the Safety tab.

^{7 1 23}

Knee osteoarthritis pain

Mixed findings

Results are mixed. The largest independent trial (262 people, JAMA 2024) found krill oil did no better than placebo for knee pain. An earlier trial (235 people) found a small extra gain in pain, stiffness and function. Two pooled analyses disagree with each other. The authors of one say krill oil is not yet justified for knee pain.

4 studiesKrill oil capsules, 2 g to 4 g a day in the trials (amounts as studie…

Studies, doses and limits

What the trials found

In the JAMA 2024 trial, 262 adults with knee pain and swelling on MRI took 2 g of krill oil or placebo for 24 weeks. Pain changed -19.9 points on krill oil and -20.2 on placebo (difference -0.3, CI -6.9 to 6.4); adverse events were 51% versus 54%. In the 2022 trial, 235 adults with mild to moderate knee osteoarthritis took 4 g of a commercial krill oil for 6 months. Pain improved a little more on krill oil (difference -5.18 on a 0-100 scale, CI -10.0 to -0.32), as did stiffness and function; funding was not stated in the abstract. A 2024 meta-analysis of 5 trials (700 people) found no difference for pain or stiffness and a small gain for function (SMD -0.24). A 2025 meta-analysis of 5 trials (730 people) found no benefit on the visual pain scale but benefit on WOMAC pain, stiffness and function (SMD about -0.6).

Results

Mixed, leaning towards no clear pain benefit: the best-designed large trial found none, and the pooled results depend on which pain scale is used.

Effect sizes as reported

JAMA 2024: pain difference -0.3 (-6.9 to 6.4). 2022 trial: -5.18 (-10.0 to -0.32). Meta-analyses: no change on pain (2024); WOMAC pain SMD -0.60 (2025).

Why this rating

Mixed: two trials point in different directions and two meta-analyses of the same few trials disagree. The larger, newer trial was null.

Form and dose studied

Krill oil capsules, 2 g to 4 g a day in the trials (amounts as studied, not advice).

Who was studied

Adults with knee osteoarthritis; the 2024 trial enrolled people with pain and MRI-swelling.

Limits

Few trials; different scales; one trial of a commercial product with funding not stated.

Why researchers looked

Omega-3 fats are thought to calm inflammation, so krill oil was tested for the swollen, painful knees of osteoarthritis.

Traditional use

Proposed mechanism Not established

Not shown. One trial author says krill oil is "rich in anti-inflammatory" omega-3s; the trials did not prove how or whether it works.

A proposed mechanism does not show that the effect happens in people.

Do not stop prescribed arthritis medicine without asking your doctor. See the Safety tab.

^{10 16 15 12}

Mood and depression

Not enough evidence

Two small studies point in different directions. In 50 adults with diagnosed depression, krill oil and fish oil both lowered depression scores more than placebo over 8 weeks. In healthy Dutch teenagers, a year of krill oil changed neither depressive feelings nor self-esteem. NCCIH says it is uncertain whether omega-3 supplements help depression at all.

3 studiesKrill oil capsules at 520 mg to 800 mg EPA plus DHA a day in trials (…

Studies, doses and limits

What the trials found

The 8-week trial of 57 adults with major depressive disorder (50 finished, about 17 per group) compared krill oil (520 mg EPA plus DHA), fish oil (600 mg) and soybean oil placebo. Hamilton depression scores fell more in both oil groups than placebo (p < 0.001), with no clear difference between the oils. The 1-year trial in Dutch adolescents from the general population found no significant effect on depression feelings or self-esteem, though adherence and drop-out were poor. NCCIH says a 2021 review of 35 studies found any effect of omega-3 on depression may be too small to matter, with low or very low quality evidence.

Results

Insufficient: one very small positive trial, one null trial in a different group, and a cautious overall picture for omega-3s.

Effect sizes as reported

Hamilton score fell significantly versus placebo in both oil groups; no significant effect in adolescents.

Why this rating

Insufficient: very small groups, short trials, and results that conflict.

Form and dose studied

Krill oil capsules at 520 mg to 800 mg EPA plus DHA a day in trials (as studied).

Who was studied

Adults with major depression (small trial); healthy adolescents (null trial).

Limits

About 17 people per group in the positive trial; poor adherence in the null trial.

Why researchers looked

Omega-3 levels are linked to mood in observational work, so researchers tested supplements.

Traditional use

Proposed mechanism Not established

Not established.

A proposed mechanism does not show that the effect happens in people.

Depression is serious. Do not replace treatment with a supplement; see a doctor.

^{2 26 23}

Omega-3 in breast milk

Very low certainty

In a pilot study of 16 breastfeeding mothers, krill oil raised the DHA and EPA in their milk over 30 days. No baby outcome was measured, so this does not show a benefit to infants.

2 studiesKrill oil supplement capsules, amounts as in the trial.

Studies, doses and limits

What the trials found

Mothers of babies in a neonatal intensive care unit took a krill oil supplement (250 mg DHA and 70 mg EPA a day) or nothing for 30 days (8 per group, not blinded). DHA in milk rose about 64% (median) versus a fall of 8% in controls, and EPA rose about 39% versus a fall of 26%. Arachidonic acid fell slightly. NCCIH says the 2020 review of 15 trials found limited evidence that omega-3 in pregnancy helps child development.

Results

Raises milk omega-3 in a very small trial. No benefit or safety result for babies.

Effect sizes as reported

DHA +64% (median change) versus -8%; EPA +39% versus -26%.

Why this rating

Very low: 16 women, not blinded, and a lab marker only.

Form and dose studied

Krill oil supplement capsules, amounts as in the trial.

Who was studied

Mothers of babies in a neonatal unit, 4 to 6 weeks after birth.

Limits

Tiny, open study; no infant outcome; no safety data for babies.

Why researchers looked

DHA matters for early brain and eye development, so mothers ask whether a supplement raises milk levels.

Traditional use

Proposed mechanism Human biomarker

The oil's fats appear in milk. This is a measured change in milk, not a health effect.

A proposed mechanism does not show that the effect happens in people.

Ask a doctor or midwife before using any supplement while breastfeeding.

^{4 23}

Memory, eyes, skin and other uses

Not enough evidence

No krill-oil-specific trial was read for memory or eyes. For omega-3 supplements in general, NCCIH says dry eye trials were no better than placebo in the large DREAM study, and adding EPA and DHA to the AREDS2 eye vitamins gave no extra benefit for macular degeneration. Evidence for memory and thinking is unclear.

1 studiesOmega-3 supplements in general, from NCCIH.

Studies, doses and limits

What the trials found

NCCIH (November 2024) says a 2018 NIH-sponsored study (DREAM, 535 people) found omega-3 supplements no better than placebo for moderate-to-severe dry eye, that AREDS2 (over 4,000 people) found adding EPA and DHA gave no additional benefit, and that a 2022 review of 33 studies suggested omega-3s may protect against cognitive decline in healthy people but had no effect in people with Alzheimer's disease. These are general omega-3 findings, not krill oil results.

Results

Insufficient for krill oil. The general omega-3 evidence is mixed or null for the eye and unclear for thinking.

Effect sizes as reported

No krill-specific numbers.

Why this rating

Insufficient: no krill oil trial read; general omega-3 evidence is mixed.

Form and dose studied

Omega-3 supplements in general, from NCCIH.

Who was studied

Adults.

Limits

Not about krill oil. Do not read these as krill oil results.

Why researchers looked

Omega-3 fats are present in the brain and the retina, so they are studied for memory and eyes.

Traditional use

Proposed mechanism Not established

Not established for krill oil.

A proposed mechanism does not show that the effect happens in people.

None specific.

²³

Connections to the rest of health

How Krill oil connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.

Explore every connection: goals, body systems, organs, symptoms, genes

Kind of connection Connected to Search

A. Wellness goals

Connected to	Evidence status	Context	Studies
Heart Health	Mixed findings	Raising EPA and DHA in the blood: Krill oil raises the blood levels of the marine omega-3 fats EPA and DHA. The open question is whether it does so better than fish oil. Three studies disagree: one found no difference when the EPA and DHA amounts were matched, a newer one found krill oil raised levels about 1.5 times more, and a pooled analysis leaned towards krill oil at lower amounts. Blood triglycerides: In pooled trials of krill oil, blood triglycerides fell by about 14 mg/dL (2017 review) and a later analysis again found lower triglycerides. A large comparison found krill oil and fish oil did not differ, and the drop depended on how much omega-3 people took. A fall in blood fat is a lab result, not fewer heart attacks.	^{20 11 14 23 18 7 9 3 1}
Heart Health	High certainty	Omega-3 EPA and DHA from seafood: The same marine omega-3 fats come from seafood. By USDA data, 3 oz (85 g) of cooked farmed Atlantic salmon has about 1.24 g DHA and 0.59 g EPA, Atlantic herring about 0.94 g DHA and 0.77 g EPA, Atlantic mackerel about 0.59 g DHA and 0.43 g EPA, and canned light tuna in water about 0.17 g DHA and 0.02 g EPA. Krill oil is not in this database.	^{25 23}
Cholesterol Balance	Moderate certainty	Blood triglycerides: In pooled trials of krill oil, blood triglycerides fell by about 14 mg/dL (2017 review) and a later analysis again found lower triglycerides. A large comparison found krill oil and fish oil did not differ, and the drop depended on how much omega-3 people took. A fall in blood fat is a lab result, not fewer heart attacks. LDL and HDL cholesterol: The pooled results on cholesterol are not consistent. A 2017 review found lower LDL ("bad") cholesterol and higher HDL ("good") cholesterol with krill oil. A 2023 review also found lower LDL and total cholesterol. But the 2020 comparison with fish oil found no clear difference, and NCCIH says EPA and DHA lower triglycerides but do not affect other blood fats.	^{18 7 9 3 23 13}
Joint Support	Mixed findings	Knee osteoarthritis pain: Results are mixed. The largest independent trial (262 people, JAMA 2024) found krill oil did no better than placebo for knee pain. An earlier trial (235 people) found a small extra gain in pain, stiffness and function. Two pooled analyses disagree with each other. The authors of one say krill oil is not yet justified for knee pain.	^{10 16 15 12}
Mood Balance	Not enough evidence	Mood and depression: Two small studies point in different directions. In 50 adults with diagnosed depression, krill oil and fish oil both lowered depression scores more than placebo over 8 weeks. In healthy Dutch teenagers, a year of krill oil changed neither depressive feelings nor self-esteem. NCCIH says it is uncertain whether omega-3 supplements help depression at all.	^{2 26 23}
Womens Wellness	Very low certainty	Omega-3 in breast milk: In a pilot study of 16 breastfeeding mothers, krill oil raised the DHA and EPA in their milk over 30 days. No baby outcome was measured, so this does not show a benefit to infants.	^{4 23}
Memory Support	Not enough evidence	Memory, eyes, skin and other uses: No krill-oil-specific trial was read for memory or eyes. For omega-3 supplements in general, NCCIH says dry eye trials were no better than placebo in the large DREAM study, and adding EPA and DHA to the AREDS2 eye vitamins gave no extra benefit for macular degeneration. Evidence for memory and thinking is unclear.	²³
Healthy Aging	Not enough evidence	Memory, eyes, skin and other uses: No krill-oil-specific trial was read for memory or eyes. For omega-3 supplements in general, NCCIH says dry eye trials were no better than placebo in the large DREAM study, and adding EPA and DHA to the AREDS2 eye vitamins gave no extra benefit for macular degeneration. Evidence for memory and thinking is unclear.	²³

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Heart Circulation	Biological association	Mixed findings	Studied for: Raising EPA and DHA in the blood Studied for: Omega-3 EPA and DHA from seafood	^{20 11 14 23 25 18 7 9 3 13 1}
Cardiovascular System	Biological association	Mixed findings	Studied for: Raising EPA and DHA in the blood Studied for: Blood triglycerides	^{20 11 14 23 18 7 9 3 1}
Nutrition	Biological association	High certainty	Studied for: Omega-3 EPA and DHA from seafood	^{25 23}
Bones Joints Muscles	Biological association	Mixed findings	Studied for: Knee osteoarthritis pain	^{10 16 15 12}
Musculoskeletal System	Biological association	Mixed findings	Studied for: Knee osteoarthritis pain	^{10 16 15 12}
Stress Mood	Biological association	Not enough evidence	Studied for: Mood and depression	^{2 26 23}
Nervous System	Biological association	Not enough evidence	Studied for: Mood and depression Studied for: Memory, eyes, skin and other uses	^{2 26 23}
Reproductive Health	Biological association	Very low certainty	Studied for: Omega-3 in breast milk	^{4 23}
Eyes	Biological association	Not enough evidence	Studied for: Memory, eyes, skin and other uses	²³

E. Health conditions

Connected to	Kind of connection	Evidence status	Context	Studies
Atrial fibrillation	Adverse effect or risk	Documented risk (marine omega 3, not krill specific)	More atrial fibrillation in large trials, stronger above 1 g a day. More atrial fibrillation in large trials of marine omega-3 supplements, stronger above 1 g a day. Preparation or compound: Marine omega-3 supplements	^{6 1}
Shellfish allergy		Laboratory finding and label caution	A shellfish allergen was tentatively detected in krill oil products. A shellfish allergen protein was tentatively detected in krill oil products. Preparation or compound: Krill oil	^{19 21}
Knee osteoarthritis		Mixed findings	The largest trial found no pain benefit; a smaller trial found a modest one. Preparation or compound: Krill oil	^{10 16}

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
Blood EPA and DHA	Biological association	Mixed findings	Measured in trials: higher. A lab change is not the same as a health benefit.	^{11 20 14}
Triglycerides	Biological association	Moderate certainty	Measured in trials: lower. A lab change is not the same as a health benefit.	^{18 9 7 3}
LDL cholesterol	Biological association	Low certainty	Measured in trials: mixed (lower in some reviews, no difference from fish oil). A lab change is not the same as a health benefit.	^{18 7 9}
HDL cholesterol	Biological association	Low certainty	Measured in trials: higher in one review (not in the comparison with fish oil). A lab change is not the same as a health benefit.	^{18 9}
Omega-3 index (red blood cell EPA plus DHA)	Biological association	Moderate certainty	Measured in trials: higher. A lab change is not the same as a health benefit.	¹⁶
Knee pain score	Biological association	Mixed findings	Measured in trials: mixed. A lab change is not the same as a health benefit.	^{10 16 15 12}
Hamilton Depression Rating Scale score	Biological association	Not enough evidence	Measured in trials: lower (very small trial). A lab change is not the same as a health benefit.	^{2 26}

J. Genes, receptors and enzymes

Connected to	Kind of connection	Evidence status	Context	Studies
APOE4	Preliminary mechanism	Human	In a 2026 trial, carriers and non-carriers of the APOE4 gene variant had similar rises in EPA and DHA with krill or fish oil.	¹¹

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Eicosapentaenoic acid (EPA)	Biological association	Human	Marine omega-3 fat; raises blood and red blood cell EPA when taken. Named by NCCIH as one of the two main studied omega-3s. Preparation or compound: Oil from Euphausia superba, mostly in phospholipids	^{16 23 11}
Docosahexaenoic acid (DHA)	Biological association	Human	Marine omega-3 fat; found in the brain and eye. PubChem lists it as doconexent. Preparation or compound: Oil from Euphausia superba, mostly in phospholipids	^{16 23 11}
Astaxanthin	Biological association	Human	Red pigment present in the krill oil used in that trial. No separate effect of astaxanthin was tested. Preparation or compound: Some krill oil products	¹⁶
Phospholipid-bound omega-3	Biological association	Human	NCCIH says krill oil contains omega-3s in the form of phospholipids. Whether this makes it better absorbed than fish oil is mixed (see Benefits). Preparation or compound: Krill oil	^{23 20 11}

Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 26, 2026).

Evidence at a glance: what changed in 1 lab markers

Tap a number to show only those markers. Counts are markers, not people.

Other1

The evidence

The research centre for Krill oil. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.

Evidence by outcome

Raising EPA and DHA in the blood 4 studies Mixed findings Omega-3 EPA and DHA from seafood 2 studies High certainty Blood triglycerides 5 studies Moderate certainty LDL and HDL cholesterol 5 studies Low certainty Very high triglycerides (a purpose-made krill extract) 1 study Low certainty Heart attacks, strokes and death 3 studies Not enough evidence Knee osteoarthritis pain 4 studies Mixed findings Mood and depression 3 studies Not enough evidence Omega-3 in breast milk 2 studies Very low certainty Memory, eyes, skin and other uses 1 study Not enough evidence

Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).

How we rate evidence

High certainty

Several well-run trials or reviews agree; further research is unlikely to change the picture much.

Moderate certainty

Good trials point the same way, but some doubt remains.

Low certainty

Small, short or inconsistent trials. The finding could change with better research.

Very low certainty

Very little or very weak human data. Treat as a possibility only.

Mixed findings

Trials or reviews disagree with each other.

Not enough evidence

Not enough human research to say either way.

Evidence against

Good research found no benefit, or found harm.

We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We started from our existing krill oil summary, then re-opened every study. We read the NCCIH omega-3 page and the FDA label text for a prescription EPA drug, re-checked food values in saved USDA FoodData Central tables, checked names in GBIF and PubChem, and re-read PubMed abstracts. Only abstracts were read for studies. The NIH Office of Dietary Supplements page was blocked and is marked unread.

Study library: every study we checked 26

Design Research type Year from Search

Study	Design	People	Product, dose, length	Result
Abdelhamid 2020 Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev · PMID 32114706 · DOI	Systematic review meta analysis	162796 86 randomised trials of at least 12 months in adults at varied heart risk	Long-chain omega-3 (EPA and DHA, mostly fish oil capsules) and plant omega-3 (ALA); krill oil not tested separately Mostly capsules 0.5 g to over 5 g a day of EPA plus DHA across trials 12 to 88 months · vs Placebo or usual diet	Raising EPA and DHA made little or no difference to all-cause death, heart events or stroke (high or moderate certainty) and may slightly lower heart-disease events and deaths (low certainty). The abstract reports arrhythmia as no difference (low certainty). Cardiovascular events RR 0.96; stroke RR 1.02; arrhythmia RR 0.99; coronary heart disease events RR 0.91 (Cardiovascular events 0.92 to 1.01; stroke 0.94 to 1.12; arrhythmia 0.92 to 1.06; CHD events 0.85 to 0.97) Methods, limits and funding Outcomes: Death, heart and circulation events, stroke, irregular heartbeat Limitations: Not a krill oil review. It is the best available picture for omega-3 capsules as a group, almost all fish oil. Funding and conflicts: Cochrane review; authors list no industry funding in the abstract. Read: abstract
Açik 2025 The effect of fish oil versus krill oil intervention on clinical symptoms and cardiometabolic risk factors in patients with major depressive disorder: A randomized placebo-controlled double-blind trial. J Affect Disord · PMID 40118278 · DOI	Randomised controlled trial	57 Adults diagnosed with major depressive disorder (50 finished)	Krill oil or fish oil Capsules Krill oil 520 mg EPA plus DHA or fish oil 600 mg EPA plus DHA a day (trial amounts) 8 weeks · vs Soybean oil placebo	Depression scores fell more in both oil groups than on placebo, with no clear difference between krill and fish oil. HDL rose in both oil groups. Scores fell significantly versus placebo (p < 0.001) in both oil groups (Not given in the abstract) Methods, limits and funding Outcomes: Hamilton Depression Rating Scale; anxiety and distress; blood fats and sugar Limitations: Very small groups (about 17 per group); 8 weeks; the authors say krill and fish oil could be an add-on, not a replacement, for treatment. Another krill trial in adolescents found no effect. Funding and conflicts: The authors report no competing interests. Read: abstract
Berge 2014 Krill oil supplementation lowers serum triglycerides without increasing low-density lipoprotein cholesterol in adults with borderline high or high triglyceride levels. Nutr Res · PMID 24461313 · DOI	Randomised controlled trial	300 Adults with borderline high or high triglycerides (150 to 499 mg/dL) who eat little fish	Krill oil Krill oil capsules 0.5, 1, 2 or 4 g a day groups (pooled for analysis) 12 weeks · vs Olive oil placebo	With the four krill oil groups pooled, triglycerides were 10.2% lower than placebo and LDL cholesterol did not rise. The authors say the large day-to-day swings in triglycerides mean a bigger study is needed. Triglycerides 10.2% lower than placebo (pooled) (Not given in the abstract) Methods, limits and funding Outcomes: Fasting triglycerides and LDL cholesterol Limitations: The four krill oil doses were pooled for the analysis because triglycerides vary a lot from day to day. Blood marker only. Funding and conflicts: Authors work for Aker BioMarine, a krill oil company, and a consulting firm; the trial is industry-linked. Read: abstract
Cimatti 2018 Maternal Supplementation With Krill Oil During Breastfeeding and Long-Chain Polyunsaturated Fatty Acids (LCPUFAs) Composition of Human Milk: A Feasibility Study. Front Pediatr · PMID 30622936 · DOI	Randomised controlled trial	16 Breastfeeding mothers of babies in a neonatal intensive care unit, 4 to 6 weeks after delivery	Krill oil supplement Krill oil capsules 250 mg DHA and 70 mg EPA a day (trial amounts) 30 days · vs No supplement (open study)	DHA and EPA in breast milk rose in the krill oil group and did not change in the control group. Arachidonic acid fell slightly. No baby outcome was measured. DHA +64% (median change) vs -8% in controls; EPA +39% vs -26% (Not given in the abstract) Methods, limits and funding Outcomes: EPA, DHA and arachidonic acid in breast milk Limitations: A feasibility study of 16 women, not blinded. It shows milk changes, not any benefit or safety for babies. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
EFSA Panel on Nutrition 2026 Scientific Opinion on the tolerable upper intake level for supplemental docosahexaenoic acid. EFSA J · PMID 41542352 · DOI	Regulator opinion n/a	EFSA scientific opinion on supplemental DHA alone (EPA to DHA ratio below 0.3)	DHA from fish oil concentrates, algal oils and krill oils with DHA alone or mostly DHA Supplements	EFSA chose the risk of spontaneous bleeding as the critical effect, could not set an upper limit, and kept a safe level of 1 g a day of supplemental DHA alone for all groups including pregnant and breastfeeding women. It applies to products with DHA alone or mostly DHA. Safe level 1 g a day of supplemental DHA alone (a regulator statement, not advice) (Not applicable) Methods, limits and funding Outcomes: Upper intake level or safe level of supplemental DHA; critical effect Limitations: It does not cover EPA-rich mixes. The krill oil in a 2022 knee trial had about twice as much EPA as DHA, so this opinion does not directly set a limit for it. Funding and conflicts: Regulator opinion (EFSA Panel on Nutrition, Novel Foods and Food Allergens). Read: abstract
Gencer 2021 Effect of Long-Term Marine ɷ-3 Fatty Acids Supplementation on the Risk of Atrial Fibrillation in Randomized Controlled Trials of Cardiovascular Outcomes: A Systematic Review and Meta-Analysis. Circulation · PMID 34612056 · DOI	Systematic review meta analysis	81210 7 large cardiovascular outcome trials of marine omega-3 supplements (average follow-up 4.9 years)	Marine omega-3 fatty acids (mostly fish oil or purified EPA; krill oil not separated) Capsules Trials at or below 1 g a day and above 1 g a day (trial amounts only) Average 4.9 years · vs Placebo	Marine omega-3 supplements were linked to a higher risk of atrial fibrillation, greater in trials above 1 g a day. All trials HR 1.25; above 1 g a day HR 1.49; 1 g a day or less HR 1.12 (All 1.07 to 1.46; above 1 g 1.04 to 2.15; 1 g or less 1.03 to 1.22) Methods, limits and funding Outcomes: New atrial fibrillation (a heart rhythm problem) Limitations: These trials did not test krill oil, so the size of the risk for krill oil is not known. Funding and conflicts: Supported in part by the US National Institutes of Health (publication type); no conflict details in the abstract. Read: abstract
Huang 2023 Clinical effectiveness of krill oil supplementation on cardiovascular health in humans: An updated systematic review and meta-analysis of randomized controlled trials. Diabetes Metab Syndr · PMID 38039646 · DOI	Systematic review meta analysis	1458 14 randomised trials (18 treatment arms)	Krill oil Krill oil supplements Trial amounts varied Varied · vs Placebo or control	Krill oil lowered total cholesterol, LDL cholesterol and triglycerides. No effect on blood pressure, blood sugar, body composition or inflammation markers. The effects were seen mainly in parallel-design trials shorter than 8 weeks and in people with BMI under 28. Total cholesterol p = 0.01; LDL p = 0.006; triglycerides p = 0.0005; no effect on other risk factors (numbers not in the abstract) (Not given in the abstract) Methods, limits and funding Outcomes: Lipid profile; blood pressure, blood sugar, body composition and inflammation markers Limitations: Lab markers only. No heart attack, stroke or death outcomes. The benefit was clearest in short trials, which may not last. Funding and conflicts: The authors declare no competing interests. Read: abstract
Jackowski 2015 Oxidation levels of North American over-the-counter n-3 (omega-3) supplements and the influence of supplement formulation and delivery form on evaluating oxidative safety. J Nutr Sci · PMID 26688721 · DOI	Laboratory analysis laboratory	171 171 over-the-counter omega-3 supplements sold in Canada (fish, krill, plant and other oils)	Omega-3 supplements including krill oil Supplements	Half of the products exceeded voluntary recommended limits for oxidation. Krill oil products had higher secondary oxidation levels than plant-based products. Capsules without flavouring had lower levels than bulk oils and flavoured products. 50% of products over voluntary limits; another 18% near the limits (Not applicable) Methods, limits and funding Outcomes: Oxidation markers (rancidity) against voluntary industry limits Limitations: Canadian products, paper published in 2015; today's products may differ. The abstract does not give a krill-only result. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Kim 2020 Lipid-modifying effects of krill oil vs fish oil: a network meta-analysis. Nutr Rev · PMID 32073633 · DOI	Network meta analysis	64 randomised trials of krill oil or fish oil; participant total not given in the abstract	Krill oil and fish oil Capsules Trial amounts varied Varied · vs Control supplements and each other	Krill oil lowered triglycerides compared with control, but krill oil and fish oil did not differ significantly on any blood fat. Triglyceride lowering depended on the amount of omega-3 consumed. Krill oil vs control: triglycerides -23.26 mg/dL. Krill vs fish oil: triglycerides -4.07, LDL +3.01, HDL +1.37, total cholesterol +1.69 mg/dL (all not significant) (Krill vs control triglycerides -38.84 to -7.69; krill vs fish oil triglycerides -15.22 to 7.08) Methods, limits and funding Outcomes: Triglycerides, LDL, HDL and total cholesterol; dose-response Limitations: Indirect comparison across many different trials. Blood markers only. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Laslett 2024 Krill Oil for Knee Osteoarthritis: A Randomized Clinical Trial. JAMA · PMID 38776073 · DOI	Randomised controlled trial	262 Adults (mean age 61.6) with knee osteoarthritis, significant knee pain and fluid or swelling in the knee on MRI; 5 Australian cities	Krill oil Krill oil capsules 2 g a day (studied in the trial) 24 weeks · vs Matching placebo	Krill oil did not improve knee pain more than placebo. Adverse events were similar (51% krill oil, 54% placebo). The authors say the findings do not support krill oil for knee pain in this group. Between-group difference in pain -0.3 points (krill oil -19.9, placebo -20.2) (-6.9 to 6.4) Methods, limits and funding Outcomes: Knee pain (0 to 100 scale) over 24 weeks Limitations: People with pain and swelling on MRI only; one dose; 15% did not finish. Funding and conflicts: No industry funding or conflicts are listed for the krill oil question in the disclosures shown; publication type lists non-US government research support. Read: abstract
Loukil 2026 Krill oil increases plasma omega-3 fatty acids more than fish oil in healthy adults: a double-blind randomized controlled trial. Am J Clin Nutr · PMID 42144109 · DOI	Randomised controlled trial	72 Healthy adults (53 women, 19 men) matched for age and BMI	Krill oil versus fish oil Krill oil (omega-3 mostly as phospholipids) or fish oil (triglycerides) About 1.1 g a day of omega-3 in both groups (amount given in the trial) 12 weeks · vs Fish oil	Krill oil raised plasma EPA and DHA about 1.5-fold more than fish oil. Women had a larger EPA rise than men. APOE4 carriers and non-carriers responded alike. About 1.5-fold greater rise in EPA and in DHA with krill oil (time-by-treatment p = 0.0001 for EPA, 0.005 for DHA) (Not given in the abstract) Methods, limits and funding Outcomes: Change in plasma EPA and DHA from baseline at weeks 1, 2, 4 and 12; effect of sex and APOE4 gene Limitations: Small trial in healthy adults; plasma levels only, no health outcome. Both groups got about 1.1 g a day of omega-3; the abstract does not say whether the EPA and DHA content matched exactly. Funding and conflicts: The authors report no conflicts of interest; funding is not stated in the abstract. Read: abstract
Meng 2025 Krill oil for knee osteoarthritis: A meta-analysis of randomized controlled trials. Medicine (Baltimore) · PMID 39960912 · DOI	Systematic review meta analysis	730 5 randomised trials in knee osteoarthritis	Krill oil Krill oil supplements Trial amounts varied Varied · vs Usual care or placebo	No significant improvement on the pain visual analogue scale, but significant gains on WOMAC pain, stiffness and function. No difference in blood markers or adverse events. The authors say the pain result needs more research. WOMAC pain SMD -0.60; stiffness -0.59; function -0.68 (Pain -0.99 to -0.21; stiffness -1.04 to -0.14; function -1.09 to -0.27) Methods, limits and funding Outcomes: Pain, stiffness and function (VAS and WOMAC), blood markers, adverse events Limitations: Some trials compared krill oil with usual care rather than placebo. The two pain scales gave different answers. Funding and conflicts: The authors declare no conflicts of interest. Read: abstract
Mozaffarian 2022 Effectiveness of a Novel ω-3 Krill Oil Agent in Patients With Severe Hypertriglyceridemia: A Randomized Clinical Trial. JAMA Netw Open · PMID 34989797 · DOI	Randomised controlled trial	520 Adults with severe hypertriglyceridemia (fasting triglycerides 500 to 1,500 mg/dL); two identical trials pooled (TRILOGY 1 and 2) in the US, Canada and Mexico	CaPre: a krill-derived omega-3 agent with EPA and DHA as phospholipids and free fatty acids (a drug-development product, not a typical supplement) Capsules 4 g a day (studied in the trial) 26 weeks · vs Placebo (cornstarch)	Triglycerides fell 26.0% on the krill agent and 15.1% on placebo at 12 weeks, a difference of 10.9 percentage points that persisted at 26 weeks. LDL, HDL and VLDL cholesterol did not differ at 12 weeks. Safety was similar to placebo. Treatment difference -10.9% at 12 weeks and -12.7% at 26 weeks (12 weeks: -20.4% to -1.5%; 26 weeks: -23.1% to -2.4%) Methods, limits and funding Outcomes: Change in fasting triglycerides at 12 and 26 weeks; other cholesterol measures; safety Limitations: A purpose-made krill extract in people with very high triglycerides, so it does not show what ordinary krill oil capsules do. Placebo group also improved by 15%. Funding and conflicts: Sponsored by Acasti Pharma. Several authors received grants or consulting fees from the sponsor; some own company stock; one holds a patent for the product. Read: abstract
Pham 2024 Comparison of Omega-3 polyunsaturated fatty acids bioavailability in fish oil and krill oil: Network Meta-analyses. Food Chem X · PMID 39974718 · DOI	Network meta analysis	26 studies (2003 to 2023) comparing omega-3 forms in people; number of participants not given in the abstract	Krill oil and fish oil in several forms Capsules, emulsions; krill oil phospholipid or free fatty acid forms Studied doses 100 to 1,900 mg for krill oil (trial amounts only) Varied · vs Fish oil forms	The authors report krill oil absorbed better than fish oil, especially at lower doses (under 2,000 mg), and warn that the results come with high heterogeneity and limited statistical significance for some measures. Krill oil (100 to 1,900 mg) and fish oil (3,000 mg and above) raised the omega-3 index; no single pooled number in the abstract (Not given in the abstract) Methods, limits and funding Outcomes: Omega-3 index, absorption measures (AUC, Cmax, Tmax) Limitations: High differences between studies. The abstract gives no pooled figures. Bioavailability, not health outcomes. Funding and conflicts: The authors declare no competing financial interests. Read: abstract
Pimentel 2024 Krill oil supplementation for knee pain: a systematic review and meta-analysis with trial sequential analysis of randomized controlled trials. Inflammopharmacology · PMID 39126570 · DOI	Systematic review meta analysis	700 5 randomised trials in people with knee pain	Krill oil Krill oil supplements Trial amounts varied Varied · vs Placebo	No significant difference from placebo for knee pain, stiffness or blood fats. A small gain in knee function. The authors conclude krill oil is not yet justified for knee pain. Function SMD -0.24; no significant effect on pain or stiffness (Function -0.41 to -0.08 (I2 = 0%)) Methods, limits and funding Outcomes: Knee pain, stiffness, function, blood fats Limitations: Only five trials. The authors say the stiffness result needs to be confirmed. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Stonehouse 2022 Krill oil improved osteoarthritic knee pain in adults with mild to moderate knee osteoarthritis: a 6-month multicenter, randomized, double-blind, placebo-controlled trial. Am J Clin Nutr · PMID 35880828 · DOI	Randomised controlled trial	235 Adults aged 40 to 65 with mild to moderate knee osteoarthritis, regular knee pain, low fish intake	A commercial krill oil supplement (with astaxanthin) Capsules 4 g krill oil a day, giving 0.60 g EPA, 0.28 g DHA and 0.45 g astaxanthin (studied in the trial) 6 months · vs Mixed vegetable oil placebo	Knee pain, stiffness and function improved in both groups, with a modest extra gain on krill oil. Omega-3 index rose from 6.0% to 8.9% on krill oil and did not change on placebo. NSAID use, blood fats and safety markers did not differ. Pain difference -5.18 points at 6 months; stiffness -6.45; function -4.67 (Pain -10.0 to -0.32; stiffness -12.1 to -0.9; function -9.26 to -0.05) Methods, limits and funding Outcomes: Knee pain, stiffness and function (WOMAC, 0 to 100); omega-3 index; safety markers Limitations: The pain result was only just significant (p = 0.04). A later, larger trial (JAMA 2024) found no benefit. Funding and conflicts: Funding is not stated in the abstract; a commercial product was tested, so ask who paid. Read: abstract
Taylor 2022 Exposure to arsenolipids and inorganic arsenic from marine-sourced dietary supplements. Chemosphere · PMID 35182530 · DOI	Laboratory analysis laboratory	32 32 marine-sourced supplements tested for arsenic; plus a pregnancy cohort survey (1,997 women)	Marine supplements including krill oil, seaweed, fish oil and Calanus oil Supplements	Total arsenic was above 1,000 ng/g in seaweed, krill and Calanus oil products. Inorganic arsenic was found only in seaweed products. Arsenic hydrocarbons were not detected in krill oil samples. Total arsenic above 1,000 ng per g in krill oil products (Not applicable) Methods, limits and funding Outcomes: Total arsenic, inorganic arsenic and arsenic hydrocarbons in supplements Limitations: Only 32 products in total, so only a few krill oil samples; the abstract does not say how many. Total arsenic includes harmless forms, so it is not a health risk figure. Funding and conflicts: The authors declare no competing interests. Read: abstract
Ursoniu 2017 Lipid-modifying effects of krill oil in humans: systematic review and meta-analysis of randomized controlled trials. Nutr Rev · PMID 28371906 · DOI	Systematic review meta analysis	662 7 randomised trials (14 treatment arms) of at least 2 weeks	Krill oil Krill oil supplements Trial amounts varied At least 2 weeks · vs Control supplements	Krill oil lowered LDL cholesterol and triglycerides and raised HDL cholesterol. Total cholesterol did not change significantly. LDL -15.52 mg/dL; triglycerides -14.03 mg/dL; HDL +6.65 mg/dL; total cholesterol -7.50 mg/dL (not significant) (LDL -28.43 to -2.61; triglycerides -21.38 to -6.67; HDL 2.30 to 10.99; total cholesterol -17.94 to 2.93) Methods, limits and funding Outcomes: Blood LDL cholesterol, HDL cholesterol, total cholesterol and triglycerides Limitations: Only 7 small trials; search ended in March 2016. Blood fats are markers, not heart attacks or strokes. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Vang 2013 Detection of tropomyosin and determination of proteins in crustacean oils. Food Chem · PMID 23768329 · DOI	Laboratory analysis laboratory	Commercial oils from Antarctic krill and the zooplankton Calanus finmarchicus (laboratory test, no people)	Krill oil products Oil	A protein tentatively identified as tropomyosin was detected in krill oil products, but not in Calanus oils. The authors say their extraction method was not ideal. Detected in krill oil products (Western blot); amount not given (Not applicable) Methods, limits and funding Outcomes: Whether tropomyosin, the main crustacean allergen, can be found in the oils Limitations: Laboratory test only; it does not show that anyone has had an allergic reaction to krill oil, and the protein amount was not measured. Funding and conflicts: No conflicts stated in the abstract. Read: abstract
Yurko-Mauro 2015 Similar eicosapentaenoic acid and docosahexaenoic acid plasma levels achieved with fish oil or krill oil in a randomized double-blind four-week bioavailability study. Lipids Health Dis · PMID 26328782 · DOI	Randomised controlled trial	66 Healthy adults, 22 per group, 28 days	Krill oil, fish oil ethyl esters or fish oil triglycerides, matched for EPA plus DHA Capsules (6 a day) About 1.3 g a day of EPA plus DHA in all three groups (amount given in the trial) 28 days · vs Two fish oil forms	No significant difference in plasma EPA plus DHA or red blood cell levels between krill oil and the two fish oil forms when the EPA and DHA amounts were matched. The authors say absorption differed by less than 24% between groups. Plasma EPA+DHA at 4 weeks: krill oil 118.5, fish oil triglyceride 108, fish oil ethyl ester 90.9 micrograms per mL (p = 0.052) (Plasma p = 0.052; red blood cells p = 0.19) Methods, limits and funding Outcomes: Plasma and red blood cell EPA plus DHA at week 4 Limitations: Only 4 weeks and 22 people per group; healthy adults only. Plasma levels, not health outcomes. Funding and conflicts: Four of the six authors work for DSM Nutritional Products, a maker of omega-3 products; the trial was run by a contract research company. Read: abstract
s-dailymed-vascepa DailyMed (FDA label): Vascepa (icosapent ethyl) prescribing information, revised 3/2026 · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-gbif-euphausia-superba GBIF Backbone Taxonomy: Euphausia superba Dana, 1850 (species key 2228010) · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-nccih-omega3 NCCIH: Omega-3 Supplements, What You Need To Know (last updated November 2024) · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-ods-omega3 NIH Office of Dietary Supplements: Omega-3 Fatty Acids fact sheet · Source	Reference database n/a			Methods, limits and funding Read: not-read
s-usda-sr-legacy-omega3 USDA FoodData Central, SR Legacy (April 2018 release): EPA and DHA in cooked fish and shrimp · Source	Reference database n/a			Methods, limits and funding Read: full-text
van der Wurff 2020 Effect of one year krill oil supplementation on depressive symptoms and self-esteem of Dutch adolescents: A randomized controlled trial. Prostaglandins Leukot Essent Fatty Acids · PMID 33232912 · DOI	Randomised controlled trial	Dutch adolescents from the general population (two cohorts); number not given in the abstract	Krill oil Krill oil capsules 400 mg then 800 mg a day of EPA plus DHA, or 800 mg from the start (trial amounts) 1 year · vs Placebo	No significant effect on depressive feelings or self-esteem after one year. The authors say poor adherence and drop-out mean the results need caution. No significant effects (Not given in the abstract) Methods, limits and funding Outcomes: Depressive symptoms (CES-D) and self-esteem Limitations: Adherence and drop-out problems. Healthy adolescents, not people with depression. Funding and conflicts: Funding is not stated in the abstract; one author was formerly with a krill oil company (Aker BioMarine). Read: abstract

What we do not know yet

No krill oil trial of heart attacks, strokes or death was read.
It is not settled whether krill oil is absorbed better than fish oil; the studies disagree.
No krill-specific study of bleeding, blood-thinner interactions or atrial fibrillation was read.
No clinical report of an allergic reaction to krill oil was read.
The NIH Office of Dietary Supplements omega-3 fact sheet was blocked and not read.
Memory, eye, skin and period-pain uses with krill oil were not researched.

How new research is added

New studies are found by a saved PubMed search and placed in a review queue before the page changes.

Lab markers

What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".

Metabolic 2

●

LDL cholesterol

Mixed (lower in some reviews, no difference from fish oil) in trials

The "bad" cholesterol carried in the blood.

Low certainty

Results and what it means

Why it was measured

To see whether krill oil, unlike most fish oil, lowers LDL.

Statistical vs. clinical meaning

Reviews conflict.

Safety implication

None specific.

Study	Result	People	Product
¹⁸	-15.52 mg/dL (95% CI -28.43 to -2.61)	7 trials, 662 people	Krill oil supplements
⁹	Krill versus fish oil +3.01 mg/dL (CI -5.49 to 11.51), not significant	64 trials	Krill oil versus fish oil

^{18 7 9}

●

HDL cholesterol

Higher in one review (not in the comparison with fish oil) in trials

The "good" cholesterol carried in the blood.

Low certainty

Results and what it means

Why it was measured

To see whether krill oil changes HDL.

Statistical vs. clinical meaning

Small change, conflicting reviews.

Safety implication

None specific.

Study	Result	People	Product
¹⁸	+6.65 mg/dL (95% CI 2.30 to 10.99)	7 trials, 662 people	Krill oil supplements
⁹	Krill versus fish oil +1.37 mg/dL (CI -3.73 to 6.48), not significant	64 trials	Krill oil versus fish oil

^{18 9}

Other 5

●

Blood EPA and DHA

Higher in trials

The amount of the omega-3 fats EPA and DHA in blood plasma, a direct measure of how much of the oil was absorbed.

Mixed findings

Results and what it means

Why it was measured

To see how well krill oil raises omega-3 levels and how it compares with fish oil.

Statistical vs. clinical meaning

It shows absorption. It does not show a health effect.

Safety implication

None specific.

Study	Result	People	Product
¹¹	About 1.5-fold greater rise in EPA and DHA with krill oil than with fish oil	72 healthy adults, 12 weeks	Krill oil versus fish oil, about 1.1 g omega-3 a day
²⁰	Krill oil 118.5, fish oil triglyceride 108, fish oil ethyl ester 90.9 micrograms per mL (not significantly different, p = 0.052)	66 healthy adults, 4 weeks	Matched EPA plus DHA

^{11 20 14}

●

Triglycerides

Lower in trials

A type of fat in the blood. High levels raise heart risk.

Moderate certainty

Results and what it means

Why it was measured

Marine omega-3 fats are known to lower triglycerides.

Statistical vs. clinical meaning

A lab-marker improvement that is consistent across reviews, not proof of fewer heart events.

Safety implication

None specific.

Study	Result	People	Product
¹⁸	-14.03 mg/dL (95% CI -21.38 to -6.67)	7 trials, 662 people	Krill oil supplements
⁹	-23.26 mg/dL versus control; krill and fish oil not significantly different	64 trials	Krill oil and fish oil

^{18 9 7 3}

●

Omega-3 index (red blood cell EPA plus DHA)

Higher in trials

The share of red blood cell fats that are EPA and DHA, a measure of long-term omega-3 status.

Moderate certainty

Results and what it means

Why it was measured

To show that krill oil actually raised omega-3 status in the knee trial.

Statistical vs. clinical meaning

Confirms the oil was absorbed. It is a status marker, not a health outcome.

Safety implication

None specific.

Study	Result	People	Product
¹⁶	Rose from 6.0% to 8.9% on krill oil; 5.5% to 5.4% on placebo (p < 0.001)	235 adults with knee osteoarthritis, 6 months	4 g krill oil a day (as studied)

¹⁶

↕

Knee pain score

Mixed results in trials

A rating of knee pain on a 0 to 100 scale (visual scale or WOMAC).

Mixed findings

Results and what it means

Why it was measured

To see whether krill oil eases knee osteoarthritis pain.

Statistical vs. clinical meaning

A pain score is a clinical symptom outcome, but the two trials disagree.

Safety implication

None specific.

Study	Result	People	Product
¹⁰	Difference versus placebo -0.3 points (CI -6.9 to 6.4)	262 adults, 24 weeks	2 g krill oil a day (as studied)
¹⁶	Difference versus placebo -5.18 points (CI -10.0 to -0.32)	235 adults, 6 months	4 g krill oil a day (as studied)

^{10 16 15 12}

●

Hamilton Depression Rating Scale score

Lower (very small trial) in trials

A clinician-rated score of depression severity.

Not enough evidence

Results and what it means

Why it was measured

To see whether krill oil lowers depression symptoms.

Statistical vs. clinical meaning

Very small groups; a null result in teenagers.

Safety implication

Depression needs medical care.

Study	Result	People	Product
²	Scores fell significantly more than placebo in both krill and fish oil groups (p < 0.001)	50 adults with major depression, 8 weeks	Krill oil (520 mg EPA plus DHA)

^{2 26}

Safety

What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.

Main points to know 5

Possible extra bleeding, especially with blood thinners. A prescription EPA fish-oil drug label (revised March 2026) warns of more bleeding in its trial, with the most bleeding in people also taking aspirin, clopidogrel or warfarin, and asks doctors to monitor. EFSA (2026) chose the risk of spontaneous bleeding as the key concern for DHA supplements. No krill-oil-specific bleeding study was read, so this is carried over by analogy, not shown for krill oil. If you take a blood thinner or an antiplatelet medicine, ask your doctor or pharmacist before using krill oil. Regulator label and opinion (analogy) ^{21 5}
Shellfish allergy. Krill are small crustaceans. A 2013 laboratory test found a protein tentatively identified as tropomyosin, the main shellfish allergen, in krill oil products. No study was read showing allergic reactions to krill oil in people. The prescription EPA label says it is not known whether people allergic to fish or shellfish are at higher risk and advises them to be told of possible reactions. If you have a shellfish allergy, ask an allergist before using krill oil. Laboratory test and regulator label ^{19 21}
Irregular heartbeat (atrial fibrillation) with marine omega-3 supplements. A 2021 meta-analysis of 7 large trials (81,210 people, average 4.9 years) found marine omega-3 supplements were linked to more atrial fibrillation (HR 1.25; 1.49 above 1 g a day; 1.12 at or below 1 g a day). These trials did not test krill oil. A larger Cochrane review of 86 trials found no difference in arrhythmia overall (RR 0.99, low certainty), so the picture is mixed. People with heart rhythm problems should ask their doctor. Meta analysis of fish oil and EPA trials (analogy) ^{6 1}
Common side effects are mild. NCCIH says side effects of omega-3 supplements are usually mild: unpleasant taste, bad breath, bad-smelling sweat, headache, and heartburn, nausea or diarrhoea. In the 2024 JAMA knee trial, 51% of the krill oil group and 54% of the placebo group had at least one adverse event. Authoritative guidance and randomised trial ^{23 10}
Product quality: oxidation and arsenic. A study of 171 omega-3 products sold in Canada found half exceeded voluntary limits for rancidity (oxidation); krill oil products had higher secondary oxidation than plant-based ones. A study of 32 marine supplements found total arsenic above 1,000 ng/g in krill oil, seaweed and Calanus products, but harmful arsenic hydrocarbons were not detected in krill oil samples and inorganic arsenic was found only in seaweed products. Laboratory studies ^{8 17}

Side effects 4

Effect	How often	Severity and recovery	Evidence
Unpleasant taste, bad breath, heartburn, nausea, diarrhoea, headache The 2022 knee trial reported that safety markers did not differ between krill oil and placebo.	Not given as a figure for krill oil. In the 2024 JAMA trial, 51% (krill oil) versus 54% (placebo) had at least one adverse event.	Usually mild Not stated in the sources read.	Authoritative guidance and randomised trial ^{23 10 16}
Bleeding (more likely with blood thinners) The label is for a prescription EPA drug from fish oil.	Not known for krill oil.	Can be serious Not stated.	Regulator label (analogy) ^{21 5}
Atrial fibrillation (irregular heartbeat) Cochrane found no difference in arrhythmia overall (RR 0.99, low certainty).	HR 1.25 (95% CI 1.07 to 1.46) in trials of marine omega-3 supplements; krill oil not separated.	Can be serious Not stated in the abstract.	Meta analysis (analogy) ^{6 1}
Allergic reaction in people allergic to shellfish A shellfish allergen protein was tentatively detected in krill oil products in 2013.	Not known; no case series read.	Not known Not known.	Laboratory test and regulator label ^{19 21}

Liver

No liver injury from krill oil was found in the sources read. A liver-safety reference (LiverTox) was not opened for this page.

How often. No frequency was found.

Monitoring. No agency monitoring advice was found.

This is a safety connection. It is not evidence that Krill oil supports liver health.

Medicines and supplements 2

With	Why it matters	Importance	Evidence	What to do
Blood thinners and antiplatelet medicines (warfarin, aspirin, clopidogrel) prescription	Omega-3 fats from fish oil are linked to more bleeding; the label says the most bleeding was in people also taking these medicines.	The prescription EPA label says to monitor people taking it together with anticoagulants or antiplatelet agents. This is a label for a fish-oil drug; no krill-oil study was read.	Regulator label (analogy) Low certainty ^{21 5}	Ask your doctor or pharmacist before combining.
Other omega-3 products (fish oil, cod liver oil, algal oil) supplement	Amounts of EPA and DHA add up across products.	NCCIH notes that fish liver oils such as cod liver oil also contain vitamins A and D, which can be harmful in excessive amounts.	Authoritative guidance Moderate certainty ²³	Check labels and tell your pharmacist about every omega-3 product you use.

Who should check first 6

Situation	Advice	Evidence
Shellfish allergy	Krill are crustaceans and a shellfish allergen was tentatively found in krill oil in a 2013 laboratory test. Ask an allergist before using it.	Laboratory test and regulator label ^{19 21}
Taking blood thinners, or having a bleeding problem	Prescription omega-3 labels warn of bleeding with these medicines. Ask a doctor or pharmacist; do not stop a medicine on your own.	Regulator label (analogy) ²¹
Atrial fibrillation or other heart rhythm problems	Marine omega-3 supplements were linked to more atrial fibrillation in large trials. Ask your doctor.	Meta analysis (analogy) ⁶
Pregnancy and breastfeeding	NCCIH says US guidance suggests 8 to 12 ounces of lower-mercury seafood a week in pregnancy and breastfeeding. One 16-woman pilot found krill oil raised omega-3 in breast milk, but no baby outcome or safety result was measured. EFSA (2026) kept a safe level of 1 g a day of supplemental DHA alone for pregnant and breastfeeding women, which does not directly cover EPA-rich krill oil. Ask a doctor or midwife before using any supplement.	Authoritative guidance, regulator opinion and small trial ^{23 4 5}
Infants and children	A one-year trial gave krill oil to Dutch adolescents; its abstract does not report side effects. No krill oil safety data for younger children were read. Do not give a child a supplement without a doctor or pharmacist's advice.	Randomised trial and gap ²⁶
Kidney or liver disease	No krill-oil-specific kidney or liver advice was read. Ask your doctor before using supplements.	Gap

Overdose, product quality and regulators

Summary. Mild stomach and taste effects are the usual problems. The main safety questions are bleeding, atrial fibrillation and shellfish allergy, none of which has been measured in krill oil specifically.

Animal. Not reviewed.

Human doses studied. Trial amounts appear only in the studies table.

High dose or long term signals. The atrial fibrillation signal in large trials was stronger above 1 g a day of marine omega-3. EFSA (2026) could not set an upper limit for DHA alone because the dose-response for bleeding is unclear.

Overdose response. Not described in the sources read. For a large accidental swallow or a severe reaction, call poison control or emergency services.

Genotoxicity. Not researched.

Oxidation (rancidity), arsenic and an allergen protein have been looked at; mercury and other pollutants in krill oil were not researched for this page.

Oxidation (rancidity). In 171 omega-3 products sold in Canada, half exceeded voluntary limits for oxidation markers. Krill oil products had higher secondary oxidation than plant-based products. Capsules without flavouring had lower levels than bulk oils. ⁸

Arsenic. Total arsenic was above 1,000 ng/g in krill, seaweed and Calanus products; arsenic hydrocarbons were not detected in krill oil; inorganic arsenic was found only in seaweed products. Total arsenic includes harmless forms. ¹⁷

Shellfish allergen. A protein tentatively identified as tropomyosin was detected in krill oil products and not in Calanus oils. ¹⁹

Body	Action	Date
NCCIH (US National Institutes of Health) (United States)	Says side effects of omega-3 supplements are usually mild, notes that krill oil contains omega-3s as phospholipids and that cod liver oil also contains vitamins A and D, and describes evidence on heart, triglycerides, depression, eye disease and pregnancy for omega-3 supplements in general. source	2024-11
US FDA (DailyMed label for Vascepa, icosapent ethyl) (United States)	Prescription EPA drug from fish oil. Warns of atrial fibrillation and flutter, of possible allergic reactions in people with fish or shellfish allergy (risk not known), and of bleeding, greater with aspirin, clopidogrel or warfarin. Applied to krill oil only by analogy. source	2026-03
EFSA (European Food Safety Authority) (European Union)	Scientific opinion on supplemental DHA alone (EPA to DHA ratio below 0.3; the opinion names krill oils among its example sources): no upper limit could be set, and the safe level of 1 g a day was kept for all groups including pregnant and breastfeeding women. Spontaneous bleeding was the critical effect. This is a regulator statement, not advice to take it. source	2026-01-14

When to get medical help

Swelling of the lips, face or throat, hives or trouble breathing after taking it: this can be a serious allergic reaction; call emergency services (people with shellfish allergy are at higher risk).
Unusual bleeding, black stools, blood in urine or vomit, or very easy bruising, especially if you take a blood thinner: get medical help.
A racing, pounding or irregular heartbeat, chest pain or fainting: get medical help.
Severe or ongoing stomach pain, vomiting or diarrhoea: stop and see a doctor.

Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.

General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.

Frequently asked questions

What is krill oil?

It is an oil made from Antarctic krill, tiny crustaceans. It supplies the marine omega-3 fats EPA and DHA, mostly as phospholipids, according to NCCIH.

^{23 22}

Is krill oil better absorbed than fish oil?

The studies disagree. A 4-week trial with matched EPA and DHA found no real difference, a 12-week trial found about a 1.5-fold bigger rise with krill oil, and a pooled analysis leaned towards krill oil with high differences between studies. These are blood levels, not health results.

^{20 11 14}

Does krill oil lower cholesterol or triglycerides?

Pooled trials found lower triglycerides, about as much as fish oil. Results on LDL and HDL cholesterol conflict between reviews. These are lab markers, not fewer heart attacks.

^{18 7 9}

Does krill oil help the heart?

Not shown. No krill oil trial of heart attacks or strokes was read. A Cochrane review of mostly fish oil trials found little or no effect on death, heart events or stroke, with a possible slight fall in coronary heart disease events (low certainty).

^{7 1}

Does krill oil help knee pain?

Mixed. The largest independent trial (JAMA 2024, 262 people) found no pain benefit over placebo. A smaller 2022 trial found a modest gain, and pooled analyses disagree. Ask your doctor about arthritis care.

^{10 16 15 12}

Does krill oil help depression?

Evidence is thin. One small trial of 50 adults found lower depression scores with krill oil than placebo; a year-long trial in healthy teenagers found no effect. NCCIH says it is uncertain whether omega-3 supplements help depression. Depression needs medical care.

^{2 26 23}

Which foods have EPA and DHA?

Fatty fish have the most. By USDA data, 3 oz of cooked farmed salmon has about 1.24 g DHA and 0.59 g EPA, and herring about 0.94 g and 0.77 g. Canned light tuna and shrimp have much less.

^{25 23}

Can people with a shellfish allergy use krill oil?

Ask an allergist first. Krill are crustaceans, and a shellfish allergen protein was tentatively found in krill oil products in a 2013 laboratory test. No study of allergic reactions to krill oil was read.

^{19 21}

Does krill oil interact with blood thinners?

It may. A prescription EPA fish-oil label warns of more bleeding with aspirin, clopidogrel or warfarin. No krill oil study was read, so this is by analogy. Ask your doctor or pharmacist.

^{21 5}

Can omega-3 supplements affect the heart rhythm?

In a 2021 meta-analysis of large trials of marine omega-3 supplements, atrial fibrillation was more common (HR 1.25), and more so above 1 g a day. Krill oil was not tested separately. A bigger Cochrane review found no difference in arrhythmia overall (low certainty).

^{6 1}

Is krill oil safe in pregnancy or for children?

Not enough is known. One 16-woman pilot showed krill oil raises omega-3 in breast milk but measured no baby outcome. US guidance reported by NCCIH suggests 8 to 12 ounces of lower-mercury seafood a week in pregnancy. Ask a doctor or midwife first, and do not give children supplements without advice.

^{4 23 5}

What are the side effects?

NCCIH says omega-3 supplement side effects are usually mild: unpleasant taste, bad breath, headache, heartburn, nausea or diarrhoea. In the 2024 JAMA knee trial, 51% on krill oil and 54% on placebo had an adverse event.

^{23 10}

Explore by health goal

Heart Health Cholesterol Balance Joint Support Mood Balance Womens Wellness Memory Support Healthy Aging

Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-26
Last substantive update: 2026-10-26
How we research: We started from our existing krill oil summary, then re-opened every study. We read the NCCIH omega-3 page and the FDA label text for a prescription EPA drug, re-checked food values in saved USDA FoodData Central tables, checked names in GBIF and PubChem, and re-read PubMed abstracts. Only abstracts were read for studies. The NIH Office of Dietary Supplements page was blocked and is marked unread.
How we rate evidence: See "How we rate evidence" in the Evidence tab.
Independence: No product is promoted on this page. No affiliate links are shown. Several krill oil trials were run by or paid for by krill oil companies; this is stated for each study.

Sources 26

Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.

Abdelhamid AS, Brown TJ, Brainard JS et al.. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease.. Cochrane Database Syst Rev. 2020. PMID 32114706. DOI 10.1002/14651858.CD003177.pub5. (abstract)
Açik M, Çakiroğlu FP, Tekin A et al.. The effect of fish oil versus krill oil intervention on clinical symptoms and cardiometabolic risk factors in patients with major depressive disorder: A randomized placebo-controlled double-blind trial.. J Affect Disord. 2025. PMID 40118278. DOI 10.1016/j.jad.2025.03.097. (abstract)
Berge K, Musa-Veloso K, Harwood M et al.. Krill oil supplementation lowers serum triglycerides without increasing low-density lipoprotein cholesterol in adults with borderline high or high triglyceride levels.. Nutr Res. 2014. PMID 24461313. DOI 10.1016/j.nutres.2013.12.003. (abstract)
Cimatti AG, Martini S, Munarini A et al.. Maternal Supplementation With Krill Oil During Breastfeeding and Long-Chain Polyunsaturated Fatty Acids (LCPUFAs) Composition of Human Milk: A Feasibility Study.. Front Pediatr. 2018. PMID 30622936. DOI 10.3389/fped.2018.00407. (abstract)
EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA), Turck D, Bohn T et al.. Scientific Opinion on the tolerable upper intake level for supplemental docosahexaenoic acid.. EFSA J. 2026. PMID 41542352. DOI 10.2903/j.efsa.2026.9858. (abstract)
Gencer B, Djousse L, Al-Ramady OT et al.. Effect of Long-Term Marine ɷ-3 Fatty Acids Supplementation on the Risk of Atrial Fibrillation in Randomized Controlled Trials of Cardiovascular Outcomes: A Systematic Review and Meta-Analysis.. Circulation. 2021. PMID 34612056. DOI 10.1161/CIRCULATIONAHA.121.055654. (abstract)
Huang H, Liao D, He B et al.. Clinical effectiveness of krill oil supplementation on cardiovascular health in humans: An updated systematic review and meta-analysis of randomized controlled trials.. Diabetes Metab Syndr. 2023. PMID 38039646. DOI 10.1016/j.dsx.2023.102909. (abstract)
Jackowski SA, Alvi AZ, Mirajkar A et al.. Oxidation levels of North American over-the-counter n-3 (omega-3) supplements and the influence of supplement formulation and delivery form on evaluating oxidative safety.. J Nutr Sci. 2015. PMID 26688721. DOI 10.1017/jns.2015.21. (abstract)
Kim MG, Yang I, Lee HS et al.. Lipid-modifying effects of krill oil vs fish oil: a network meta-analysis.. Nutr Rev. 2020. PMID 32073633. DOI 10.1093/nutrit/nuz102. (abstract)
Laslett LL, Scheepers LEJM, Antony B et al.. Krill Oil for Knee Osteoarthritis: A Randomized Clinical Trial.. JAMA. 2024. PMID 38776073. DOI 10.1001/jama.2024.6063. (abstract)
Loukil I, Vachon A, Çaku A et al.. Krill oil increases plasma omega-3 fatty acids more than fish oil in healthy adults: a double-blind randomized controlled trial.. Am J Clin Nutr. 2026. PMID 42144109. DOI 10.1016/j.ajcnut.2026.101346. (abstract)
Meng J, Wang X, Li Y et al.. Krill oil for knee osteoarthritis: A meta-analysis of randomized controlled trials.. Medicine (Baltimore). 2025. PMID 39960912. DOI 10.1097/MD.0000000000041566. (abstract)
Mozaffarian D, Maki KC, Bays HE et al.. Effectiveness of a Novel ω-3 Krill Oil Agent in Patients With Severe Hypertriglyceridemia: A Randomized Clinical Trial.. JAMA Netw Open. 2022. PMID 34989797. DOI 10.1001/jamanetworkopen.2021.41898. (abstract)
Pham TP, Hoang TV, Cao PT et al.. Comparison of Omega-3 polyunsaturated fatty acids bioavailability in fish oil and krill oil: Network Meta-analyses.. Food Chem X. 2024. PMID 39974718. DOI 10.1016/j.fochx.2024.101880. (abstract)
Pimentel T, Queiroz I, Florêncio de Mesquita C et al.. Krill oil supplementation for knee pain: a systematic review and meta-analysis with trial sequential analysis of randomized controlled trials.. Inflammopharmacology. 2024. PMID 39126570. DOI 10.1007/s10787-024-01543-7. (abstract)
Stonehouse W, Benassi-Evans B, Bednarz J et al.. Krill oil improved osteoarthritic knee pain in adults with mild to moderate knee osteoarthritis: a 6-month multicenter, randomized, double-blind, placebo-controlled trial.. Am J Clin Nutr. 2022. PMID 35880828. DOI 10.1093/ajcn/nqac125. (abstract)
Taylor VF, Karagas MR. Exposure to arsenolipids and inorganic arsenic from marine-sourced dietary supplements.. Chemosphere. 2022. PMID 35182530. DOI 10.1016/j.chemosphere.2022.133930. (abstract)
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.. Nutr Rev. 2017. PMID 28371906. DOI 10.1093/nutrit/nuw063. (abstract)
Vang B, Mæhre HK, Jensen IJ et al.. Detection of tropomyosin and determination of proteins in crustacean oils.. Food Chem. 2013. PMID 23768329. DOI 10.1016/j.foodchem.2013.02.125. (abstract)
Yurko-Mauro K, Kralovec J, Bailey-Hall E et al.. Similar eicosapentaenoic acid and docosahexaenoic acid plasma levels achieved with fish oil or krill oil in a randomized double-blind four-week bioavailability study.. Lipids Health Dis. 2015. PMID 26328782. DOI 10.1186/s12944-015-0109-z. (abstract)
. DailyMed (FDA label): Vascepa (icosapent ethyl) prescribing information, revised 3/2026. . . (full-text)
. GBIF Backbone Taxonomy: Euphausia superba Dana, 1850 (species key 2228010). . . (full-text)
. NCCIH: Omega-3 Supplements, What You Need To Know (last updated November 2024). . . (full-text)
. NIH Office of Dietary Supplements: Omega-3 Fatty Acids fact sheet. . . (not-read)
. USDA FoodData Central, SR Legacy (April 2018 release): EPA and DHA in cooked fish and shrimp. . . (full-text)
van der Wurff ISM, von Schacky C, Bergeland T et al.. Effect of one year krill oil supplementation on depressive symptoms and self-esteem of Dutch adolescents: A randomized controlled trial.. Prostaglandins Leukot Essent Fatty Acids. 2020. PMID 33232912. DOI 10.1016/j.plefa.2020.102208. (abstract)

Where to buy

Check the label first. Whatever you buy, look for these:

The amount of the active ingredient per serving, not just the front-label claim
A third-party testing mark (USP, NSF or ConsumerLab)
Other ingredients and allergens
Ask a pharmacist about interactions with your medicines

Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.

Browse Krill oil on Amazon

Amazon · Several brands to compare

Shop Krill oil on Amazon

Support our free guides: as an Amazon Associate we earn from qualifying purchases. Full disclosure.

Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.