Krill Oil vs Fish Oil: Bioavailability, Phospholipids and What Research Shows

Krill oil and fish oil both provide the long-chain omega-3 fatty acids EPA and DHA, but they do not deliver those fatty acids in exactly the same lipid structure.

In krill oil, a substantial portion of EPA and DHA can be associated with phospholipids. Fish-oil supplements, by comparison, can provide EPA and DHA in several forms, including triglycerides, re-esterified triglycerides, ethyl esters, free fatty acids, and emulsified systems.

That difference has led to one of the most common questions in omega-3 supplementation:

Is krill oil absorbed better than fish oil?

The most accurate answer is: sometimes, depending on the formulation, dose, study design, and measurement used—but there is no universal percentage or rule that applies to every krill oil and every fish oil.

“Bioavailability is a property of a specific dose and formulation measured under specific conditions—not a permanent ranking of ‘krill oil’ over ‘fish oil.’”

What Is the Main Difference Between Krill Oil and Fish Oil?

Both krill oil and fish oil can provide EPA and DHA.

The most important structural difference is the lipid form in which those omega-3 fatty acids are delivered.

Krill Oil

Krill oil commonly contains:

• EPA
• DHA
• Phospholipids
• Naturally occurring astaxanthin
• Other components of the krill lipid matrix

A meaningful portion of EPA and DHA in krill oil can be associated with phospholipids.

Fish Oil

“Fish oil” is not one single formulation.

EPA and DHA in fish-oil supplements may occur as:

• Natural triglycerides
• Re-esterified triglycerides
• Ethyl esters
• Free fatty acids
• Emulsified or other delivery systems

This matters because comparing “krill oil” with “fish oil” without identifying the actual fish-oil form can oversimplify the evidence.

The National Institutes of Health notes that omega-3 supplements are available in several chemical forms. Re-esterified triglycerides, natural triglycerides, and free fatty acids may have somewhat higher bioavailability than ethyl esters, but all of these forms can increase plasma EPA and DHA.

What Are Phospholipids?

Phospholipids are a major class of lipids found throughout biological membranes.

They contain both a water-interacting region and a fat-interacting region. This amphiphilic structure gives them different physicochemical properties from completely nonpolar fats.

In krill oil, a portion of EPA and DHA can be associated with these phospholipids.

That is a real chemical difference—but it should not be interpreted to mean that phospholipid-bound omega-3s:

• Bypass digestion
• Move directly from a capsule into human cells
• Require no normal digestive processing
• Automatically reach organs more efficiently
• Are always absorbed at a fixed percentage more than fish oil

Dietary lipids still undergo digestion, absorption through the intestine, incorporation into transport particles, and circulation through normal physiological pathways.

What Does “Bioavailability” Actually Mean?

The word bioavailability is often used as if it represents one simple number.

In omega-3 research, however, scientists can measure several different outcomes.

AUC — Area Under the Curve

AUC estimates total blood exposure to a substance over a defined period after supplementation.

Cmax — Maximum Concentration

Cmax is the highest concentration measured after a dose.

Tmax — Time to Maximum Concentration

Tmax describes how long it takes to reach that measured peak.

Plasma EPA and DHA

Plasma fatty-acid concentrations can respond relatively quickly to recent omega-3 intake.

Red-Blood-Cell EPA and DHA

Red-blood-cell fatty acids generally reflect longer-term incorporation than a single plasma measurement.

Omega-3 Index

The Omega-3 Index refers to EPA plus DHA in red-blood-cell membranes expressed as a percentage of total red-cell fatty acids.

These outcomes are related—but they are not interchangeable.

A supplement that produces a higher short-term plasma concentration does not automatically produce stronger cardiovascular, cognitive, joint, or other clinical outcomes.

What Do Human Studies Show About Krill Oil vs Fish Oil?

Several human trials have compared krill oil with specific fish-oil formulations.

The results are useful, but they need to be interpreted according to the formulation, EPA and DHA dose, study population, duration, and biomarker measured.

2011: Similar EPA and DHA Changes Despite Different Doses

A randomized seven-week study assigned participants to krill oil, fish oil, or no omega-3 supplementation.

The daily study doses provided:

• Krill oil: 3.0 g oil providing 543 mg EPA + DHA
• Fish oil: 1.8 g oil providing 864 mg EPA + DHA

Both supplemented groups showed significant increases in plasma EPA and DHA compared with the control group.

Despite the krill-oil group receiving substantially less EPA+DHA, the study did not find a statistically significant difference between the krill- and fish-oil groups in the magnitude of the increases in plasma EPA and DHA.

This finding suggests that the krill formulation tested delivered EPA and DHA efficiently.

But it should not be converted into a rule that 543 mg from any krill oil always equals 864 mg from any fish oil.

The study used particular products, particular fatty-acid ratios, and a specific population.

2013: Krill Oil Increased the Omega-3 Index More Than the Fish Oil Used in the Trial

A double-blind randomized crossover study included 24 healthy adults.

Participants received krill oil, fish oil, and placebo during separate treatment periods. Both marine-oil treatments provided 600 mg of omega-3 fatty acids per day for four weeks.

In this trial, krill oil produced greater increases in several plasma and red-blood-cell omega-3 measurements, including the Omega-3 Index, compared with the fish-oil preparation used in the study.

That provides evidence in favor of the specific krill formulation tested.

However, the study was small, and the result should not be treated as a universal ranking of every krill oil over every fish oil.

2015: A Single-Dose Study Found Higher 72-Hour Exposure With Krill Oil

A randomized crossover trial included 15 healthy participants.

Researchers compared krill oil, krill meal, and fish oil during separate single-dose test periods and measured EPA and DHA in plasma lipids over 72 hours.

The primary analysis found a greater incremental area under the curve for EPA and DHA in plasma phospholipids after the krill-oil preparation than after the fish-oil preparation.

However, the study produced an especially important caution.

Krill meal also contained phospholipid-associated EPA and DHA, yet its bioavailability did not differ significantly from fish oil.

The authors therefore concluded that the results argued against simply assuming that phospholipids themselves are always better absorbed than triglycerides.

The study also showed substantial person-to-person variability and called for longer-term trials using biomarkers that better reflect tissue omega-3 status.

2024: What Did the Network Meta-Analysis Find?

A 2024 network meta-analysis examined 26 studies involving different omega-3 sources, molecular forms, and doses.

The analysis reported favorable bioavailability findings for some lower-dose krill-oil comparisons and found that certain krill-oil formulations ranked highly for selected measures such as AUC and Omega-3 Index.

However, the results also showed why broad conclusions require caution.

The studies differed in:

• Dose
• Omega-3 chemical form
• Krill- and fish-oil formulation
• Study design
• Duration
• Bioavailability endpoint

The authors specifically noted high heterogeneity and uncertainty around some comparisons.

The analysis also found that certain fish-oil emulsions performed strongly for Cmax, again showing that fish oil is not one uniform delivery system.

2026: A New Randomized Trial Reported Higher Plasma EPA and DHA With Krill Oil

A 2026 double-blind randomized clinical trial included 72 healthy adults.

Participants received approximately 1.1 g/day of omega-3 fatty acids from either krill oil or fish oil for 12 weeks.

The krill-oil group showed greater increases from baseline in plasma EPA and DHA than the fish-oil group used in the study.

At 12 weeks, the increase in EPA was approximately 1.4 times higher and the increase in DHA approximately 1.5 times higher in the krill-oil group.

This is important recent evidence that the phospholipid-rich krill-oil formulation tested can produce higher circulating EPA and DHA than the triglyceride fish-oil formulation used as the comparator.

But it still does not establish that:

• Every krill oil is 1.5 times more bioavailable than every fish oil
• The same difference occurs at all doses
• The same difference occurs with other fish-oil forms
• Higher plasma EPA and DHA automatically produce superior clinical outcomes

The result belongs to the specific formulation, comparator, dose, population, duration, and outcome studied.

Is Krill Oil Really “48% More Bioavailable” Than Fish Oil?

There is no universal 48% bioavailability advantage that applies to every krill-oil and fish-oil supplement.

A fixed percentage removes too much important context.

Studies differ in:

• The krill-oil preparation
• The fish-oil preparation
• The EPA and DHA dose
• The ratio of EPA to DHA
• The molecular form of the omega-3s
• Whether supplements were taken with food
• Study duration
• The population studied
• The biomarker measured

A more defensible interpretation is:

“Some krill-oil formulations have produced higher EPA and DHA exposure or greater increases in selected omega-3 biomarkers than specific fish-oil formulations in human studies, but the size and clinical significance of that difference are not universal.”

Does Krill Oil Bypass Digestion?

No.

The fact that phospholipids are major components of cell membranes does not mean dietary phospholipids travel intact from a supplement directly into human cell membranes.

Dietary fats still undergo normal gastrointestinal digestion and absorption.

According to the NIH, dietary lipids are processed in the intestinal tract, incorporated into micelles, absorbed by intestinal cells, and subsequently transported through normal lipid-transport pathways.

Therefore, statements such as:

• “Krill oil bypasses digestion”
• “Phospholipid omega-3 goes directly into your cells”
• “Krill oil does not need to be digested”

should not be treated as accurate descriptions of human physiology.

Does Krill Oil Cause Fewer Fishy Burps?

Some people may find one marine-oil formulation easier to tolerate than another.

But krill oil cannot be guaranteed to prevent:

• Fishy aftertaste
• Reflux
• Heartburn
• Nausea
• Other gastrointestinal discomfort

Individual tolerance, dose, oxidation, capsule design, timing, food intake, and overall formulation can all influence the experience.

The statement that krill oil causes “no reflux because it is water-soluble” is therefore too broad.

Does Astaxanthin Make Krill Oil More Bioavailable?

Astaxanthin is a naturally occurring carotenoid responsible for much of krill oil’s characteristic reddish color.

It has antioxidant activity and distinguishes krill oil compositionally from many conventional fish oils.

However, the presence of astaxanthin does not by itself prove that a krill-oil supplement:

• Is absorbed better
• Produces stronger clinical outcomes
• Cannot oxidize
• Protects every omega-3 molecule from degradation

The actual astaxanthin amount, preparation, storage conditions, packaging, oil composition, and outcome studied all matter.

For a broader explanation of EPA and DHA, phospholipids, astaxanthin, potential benefits, and safety, read What Is Krill Oil? Omega-3s, Phospholipids, Astaxanthin, Benefits and Safety .

Krill Oil vs Fish Oil: What Should You Actually Compare?

Which Usually Contains More EPA and DHA: Krill Oil or Fish Oil?

There is no fixed answer because formulations vary widely.

However, many concentrated fish-oil supplements can provide relatively large amounts of EPA and DHA in a small number of capsules.

Krill oil may contain a lower concentration of EPA and DHA per gram of total oil while also providing phospholipids and naturally occurring astaxanthin.

This is why comparing products only by statements such as:

“500 mg krill oil” vs “1,000 mg fish oil”

is not very informative.

The better question is:

How much EPA and DHA does each daily serving actually provide, and in what formulation?

Does a Lower Dose of Krill Oil Equal a Higher Dose of Fish Oil?

Not automatically.

Some studies have found comparable or greater changes in omega-3 biomarkers with lower EPA+DHA intakes from particular krill-oil preparations.

But there is no validated universal conversion such as:

“X mg of krill oil always equals Y mg of fish oil.”

Dose equivalence would depend on the actual EPA and DHA amount, formulation, duration, individual response, and outcome being considered.

How Does RevitaPlus Beauty Pack Compare With the Doses Used in Krill-Oil Studies?

RevitaPlus Beauty Pack includes an Antarctic krill-oil component as one of its six daily supplement components.

The current public Supplement Facts information lists:

• Antarctic Krill Oil — 500 mg
• Total Omega-3s (EPA/DHA) — 200 mg
• Phospholipids — 200 mg
• Astaxanthin — 150 mcg

Many of the krill-oil bioavailability trials discussed above used substantially higher EPA+DHA intakes than the amount provided by the Beauty Pack krill-oil component.

For example:

• The 2011 krill-oil group received 543 mg EPA+DHA per day.
• The 2013 crossover study provided 600 mg omega-3 fatty acids per day.
• The 2015 acute study used approximately 1.4 g EPA+DHA from the krill-oil treatment.
• The 2026 randomized trial provided approximately 1.1 g omega-3 fatty acids per day.

Those differences matter.

The pharmacokinetic findings from those studies should not automatically be attributed to Beauty Pack.

Ingredient Research Is Not Finished-Product Research

This distinction is particularly important in bioavailability comparisons.

A study may use:

• A proprietary krill-oil ingredient
• A specific phospholipid concentration
• A specific EPA and DHA dose
• A particular fish-oil comparator
• A standardized meal
• A defined healthy population
• A particular biomarker
• A treatment period ranging from one dose to several months

If another supplement has a different composition or substantially different EPA and DHA amount, the study result does not automatically transfer to that product.

So, Is Krill Oil Better Than Fish Oil?

There is no universal winner.

Krill oil has a distinctive phospholipid-rich lipid profile, and several human studies have reported favorable EPA and DHA bioavailability outcomes for particular krill-oil formulations.

Fish oil, however, is available in many forms and can provide high concentrations of EPA and DHA. Some modern fish-oil delivery systems also perform strongly on pharmacokinetic measures.

The more useful comparison depends on what matters to you:

• Actual EPA and DHA dose
• Chemical form
• Long-term omega-3 status
• Serving size and capsule burden
• Tolerability
• Product quality
• Cost
• The specific outcome supported by research

The label and formulation matter more than simply assuming that one marine source is always superior.

The Key Takeaway

Krill oil and fish oil both provide EPA and DHA, but their lipid structures and formulations can differ substantially.

Krill oil commonly provides a meaningful portion of its omega-3 fatty acids in association with phospholipids, while fish-oil supplements may use triglycerides, re-esterified triglycerides, ethyl esters, emulsions, or other delivery systems.

Human studies show that some krill-oil preparations can perform favorably on selected measures of EPA and DHA bioavailability.

However, the research does not justify reducing the entire comparison to statements such as:

• “Krill oil is always 48% more bioavailable.”
• “Phospholipids bypass digestion.”
• “Krill oil enters cells directly.”
• “A small krill-oil dose always replaces a larger fish-oil dose.”

Instead, compare:

• The actual EPA and DHA amount
• The omega-3 chemical form
• The complete formulation
• The dose used in the research
• The population studied
• The study duration
• The biomarker or clinical outcome measured

Those details provide a much clearer interpretation than treating all krill oils—and all fish oils—as interchangeable products.

This article is for general educational purposes and is not a substitute for medical advice, diagnosis, or treatment.