Quick answer: Krill oil does contain astaxanthin, the same red pigment sold in dedicated capsules, but in far smaller amounts. Real product labels show roughly 0.08 mg to 0.75 mg of astaxanthin per gram of oil, so a typical 1 to 3 gram daily dose of krill oil delivers well under 2.3 mg. A dedicated astaxanthin supplement delivers 4 mg to 12 mg a day, several times more. Krill oil’s real selling point is its phospholipid-bound omega-3 fatty acids, not its astaxanthin content. Take krill oil for the omega-3s. Take a separate astaxanthin capsule if the pigment itself is the goal.
What Astaxanthin and Krill Oil Actually Are
Astaxanthin is a red-orange carotenoid pigment. It is produced naturally by the microalga Haematococcus pluvialis, and it shows up in salmon, shrimp, and krill because those animals eat algae, or eat smaller creatures that already concentrated it, and store it in their tissue and shells.
Krill oil is a different product entirely. It is oil extracted from Antarctic krill (Euphausia superba), a small shrimp-like crustacean harvested from the Southern Ocean. Its main selling point is omega-3 fatty acids, EPA and DHA, delivered mostly as phospholipids rather than the triglyceride form found in standard fish oil. Astaxanthin is what gives krill and krill oil their reddish color, but by weight it is a minor trace component, not the reason people buy krill oil. For a full walkthrough of astaxanthin on its own, see what astaxanthin actually is and where it comes from.
Astaxanthin vs Krill Oil: How Much Pigment Is Actually in the Oil?
This is where the astaxanthin vs krill oil comparison gets concrete. Astaxanthin content in krill oil is not fixed. It depends on the extraction method, the krill batch, and how the product is standardized, and published figures for krill oil and krill meal range from about 40 mg per kg up to several thousand mg per kg for concentrated extracts, according to a comparative review of krill and fish oil research (PMC).
Retail labels tell a more useful story than that wide research range. Two real Antarctic krill oil products list astaxanthin at 40 mcg per 500 mg softgel and 750 mcg per 1,000 mg softgel, which work out to about 0.08 mg and 0.75 mg per gram of oil. A 2014 safety study on Superba krill powder measured 115.5 mg of astaxanthin per kg of powder, about 0.12 mg per gram, in the batch it tested (Toxicology Reports).
| Source | Astaxanthin content | What it is based on |
|---|---|---|
| Retail Antarctic krill oil softgel, product A | 40 mcg per 500 mg softgel (about 0.08 mg per gram of oil) | Published product label |
| Retail krill oil softgel, product B | 750 mcg per 1,000 mg softgel (about 0.75 mg per gram of oil) | Published product label |
| Superba krill powder, tested batch | 115.5 mg per kg (about 0.12 mg per gram) | 2014 rat safety study, Toxicology Reports |
| Typical krill oil dose, 1 to 3 grams a day | Roughly 0.08 mg to 2.3 mg of astaxanthin a day | Calculated from the label range above |
| Dedicated astaxanthin capsule | 4 mg to 12 mg a day | Standard consumer dosing range |
Do the math on a normal krill oil dose and even the high end of that range does not reach what one dedicated astaxanthin capsule provides at its low end. If your goal is a measured astaxanthin dose, for example one used in a specific trial, krill oil is not the vehicle for it. See how astaxanthin dosing is set by goal for the ranges researchers actually test.
The briefing
One honest health-science email a week
Plain-English breakdowns of supplement trials, biomarkers, and what the evidence does and does not support. Written for people who want the caveats, not the hype.
Krill Oil vs Fish Oil: Does the Phospholipid Form Actually Matter?
Krill oil’s omega-3 fatty acids are bound mostly to phospholipids, while standard fish oil delivers them as triglycerides or, in concentrated products, as ethyl esters. This structural difference is the actual argument for krill oil, separate from astaxanthin entirely.
A 2011 crossover study in 12 healthy men gave a single dose of 1,680 mg combined EPA and DHA from krill oil, fish oil triglycerides, or fish oil ethyl esters, then tracked blood levels for 72 hours. Krill oil produced the highest incorporation of EPA and DHA into plasma phospholipids of the three forms, though the difference was not statistically significant because individual responses varied widely (Lipids in Health and Disease, 2011).
A separate 2013 trial in 24 healthy adults compared 3 grams a day of krill oil against fish oil and corn oil over 4 weeks, with each treatment providing about 600 mg of combined EPA and DHA. The omega-3 index rose more with krill oil than with fish oil, a roughly twofold difference (1.04 percentage points versus 0.47), in a longer trial matching daily doses rather than a single dose (Lipids in Health and Disease, 2013).
Read those two results together and the pattern is consistent, not proven. The direction favors krill oil for absorption efficiency at matched EPA and DHA doses, but the sample sizes are small (12 and 24 people) and neither trial ran long enough to tell you whether that absorption edge changes a hard health outcome. For a side by side on the omega-3 question specifically, see astaxanthin and fish oil compared directly.
Krill Oil for Cholesterol: What the Trials Actually Show
Krill oil for cholesterol has real trial support, though it is mixed at the level of individual studies. A 2017 systematic review and meta-analysis pooled 7 randomized controlled trials with 662 participants and found krill oil supplementation significantly reduced LDL cholesterol by about 15.5 mg per dL and triglycerides by about 14 mg per dL, and raised HDL cholesterol by about 6.7 mg per dL. Total cholesterol dropped too, but that change did not reach statistical significance across the pooled trials (Nutrition Reviews, 2017).
That pooled result sits on top of individual trials that disagree with each other. Some smaller trials reported krill oil outperforming fish oil for LDL reduction, and at least one larger trial in people with high triglycerides found no significant lipid improvement at all after 12 weeks. A meta-analysis smooths that inconsistency into an average, it does not erase it. If cholesterol is your main reason for considering either supplement, that is a conversation for your own clinician using your own lipid panel, not a supplement label.
Antarctic Krill Oil Benefits Beyond Cholesterol
Antarctic krill oil benefits studied in humans and animals extend past lipids into inflammation and oxidative stress markers, though this evidence is earlier stage. A comparative analysis of krill oil and fish oil research describes both oils producing similar reductions in inflammatory and oxidative stress markers in animal models, with one 2024 rat study of induced ulcers finding astaxanthin itself, dosed separately, outperformed either whole oil on markers like malondialdehyde and myeloperoxidase activity (PMC).
That last point matters for this comparison specifically: when a benefit is driven by astaxanthin’s antioxidant action rather than by omega-3 fatty acids, krill oil’s trace astaxanthin content is unlikely to deliver it at a meaningful dose. General krill oil benefits research, separate from astaxanthin, includes small trials on joint comfort and knee pain, and animal work on fat metabolism. None of this rises to the level of a treatment claim, and most trials remain small, short, or funded by ingredient suppliers.
Krill Oil Dangers and Side Effects Worth Knowing
Krill oil dangers that are actually documented are limited and mostly predictable. Krill is a crustacean, so anyone with a shellfish or seafood allergy should avoid krill oil the same way they would avoid shrimp. Mild digestive effects, including a fishy aftertaste or loose stool, are reported with krill oil the same way they are with fish oil, usually easing when taken with food.
A 13 week toxicology study in rats fed krill powder at doses equivalent to roughly 5,000 to 6,000 mg per kg of body weight per day found no adverse effects on blood chemistry or overall health, and set the no observed adverse effect level at the highest dose tested. Minor findings, like small liver cell changes in males, were judged non-adverse by the study authors (Toxicology Reports, 2014). That is animal safety data at doses far above typical human supplement use, not a human safety trial, and it says nothing about astaxanthin specifically since astaxanthin was a trace component of the powder tested. Anyone on blood thinners should also know that omega-3 fatty acids, from krill oil or fish oil, can add to bleeding risk at high doses, which is a conversation to have with a prescriber before combining them. For a broader rundown of what is documented versus rumored for astaxanthin itself, see astaxanthin side effects that are actually documented.
Should You Take Astaxanthin, Krill Oil, or Both?
Match the supplement to the goal instead of assuming one covers the other.
- If you want measured astaxanthin, at a dose that matches what a trial actually tested, take a dedicated astaxanthin capsule. Krill oil cannot reliably get you there. See the full astaxanthin supplement guide for dose ranges by goal.
- If you want omega-3 fatty acids and you tolerate a phospholipid-bound form well, or you have struggled with fishy burps on standard fish oil, krill oil is a reasonable choice, at a typically higher price per gram of EPA and DHA than fish oil.
- If you want both effects, taking a fish oil or krill oil product for omega-3s and a separate astaxanthin capsule for pigment dose is the only way to control both numbers independently. Nothing stops you from taking both; they are not known to interact.
- If you have a shellfish allergy, krill oil is off the table regardless of which benefit you are chasing. Algae-derived astaxanthin and algae-derived omega-3 products avoid that specific risk.
How to Choose Between Krill Oil Products, If You Want One
Looking for the best krill oil supplement or the best krill oil for a specific goal comes down to reading the label carefully rather than trusting marketing claims about astaxanthin content, since this article shows how widely that number swings between products. Check the milligrams of EPA and DHA per serving first, since that is what most of the trial evidence actually measured. Check whether the astaxanthin amount is even disclosed. Many krill oil labels list only “astaxanthin” as a natural component without a milligram figure, which tells you it is present but not how much. Look for third-party testing for heavy metals and oxidation (a rancid, overly fishy smell out of the bottle is a practical warning sign). Source species matters too: Antarctic krill (Euphausia superba) from a certified fishery is the species behind almost all the human trial data cited here, so a product naming a different or unspecified krill species is harder to evaluate against the research.
What Would Change This Answer
A trial that measured astaxanthin blood levels after a normal krill oil dose, rather than just the omega-3 fatty acid levels, would settle the pigment-dose question with real numbers instead of label math. A head to head trial testing krill oil against a combination of fish oil plus a separate astaxanthin capsule, on the same inflammation or cholesterol outcomes, would also clarify whether krill oil’s “two benefits in one” pitch holds up against just taking both ingredients separately. Until those trials exist, this comparison rests on published label data and separate lines of research on omega-3 absorption and astaxanthin dosing, not on a single study that tested the exact question “astaxanthin vs krill oil” head to head.
Frequently Asked Questions
Does krill oil have enough astaxanthin to matter?
Not usually, based on the same milligrams researchers use in astaxanthin-specific trials. Real product labels show roughly 0.08 mg to 0.75 mg of astaxanthin per gram of krill oil, so a typical 1 to 3 gram daily dose delivers under 2.3 mg. Most human astaxanthin trials use 4 mg to 12 mg a day, a dose krill oil alone does not reach.
Is krill oil better than fish oil?
For omega-3 absorption at matched doses, small trials suggest krill oil’s phospholipid form may be incorporated into blood phospholipids somewhat more efficiently than fish oil’s triglyceride or ethyl ester forms, though results vary between trials and sample sizes are small. For cholesterol, a pooled analysis of 7 trials found meaningful LDL, triglyceride, and HDL improvements with krill oil. Neither oil has been shown to prevent disease.
Can you take astaxanthin and krill oil together?
Yes. They are not known to interact, and taking both simply means you are separately controlling your omega-3 dose and your astaxanthin dose rather than hoping one product covers both. This is the practical answer for anyone who wants a specific, trial-matched astaxanthin amount alongside omega-3s.
What are the main krill oil benefits supported by human trials?
The strongest human evidence is for lipid markers: a 2017 meta-analysis of 662 people across 7 trials found reduced LDL cholesterol and triglycerides and increased HDL cholesterol with krill oil supplementation. Smaller trials have looked at joint comfort and omega-3 blood levels. Evidence for other claimed benefits remains preliminary or animal-based.
What are the real krill oil dangers to know about?
Krill is a crustacean, so a shellfish allergy is a real contraindication. Mild digestive upset and a fishy aftertaste are the most commonly reported effects. High-dose omega-3 intake, from krill oil or fish oil, can add to bleeding risk in people on blood thinners. A 13-week animal safety study found no adverse effects at doses far above typical human use, which is reassuring but is not human safety data.
Does krill oil help cholesterol more than fish oil?
Some individual trials found krill oil outperformed fish oil for LDL reduction, while at least one larger trial found no significant lipid change with krill oil after 12 weeks. A 2017 meta-analysis found krill oil overall reduced LDL and triglycerides and raised HDL, but did not directly rank it against fish oil across all included trials. The honest answer is that the evidence favors krill oil having a real lipid effect, not that it has been proven superior to fish oil.
How do I know how much astaxanthin is in my krill oil?
Check the supplement facts panel for a specific milligram or microgram figure next to “astaxanthin.” Many labels list astaxanthin as present without a number, which means you cannot calculate a dose from that product. If the label gives no figure, assume you are getting a trace amount, well under 1 mg per typical serving based on the labeled products reviewed here.
Should I pick krill oil or a dedicated astaxanthin supplement?
Pick based on which number you are trying to control. If you want a specific astaxanthin dose matching what a trial tested, use a dedicated astaxanthin capsule. If you want omega-3 fatty acids and prefer a phospholipid-bound form, krill oil fits that goal. They solve different problems even though both come from the same reddish pigment family.
This article is for informational purposes and does not replace medical advice. Astaxanthin and krill oil are dietary supplements, not treatments for any disease. Talk with your own doctor or pharmacist before starting either one, especially if you are pregnant, breastfeeding, have a shellfish allergy, take blood thinners or blood pressure medication, or manage a chronic health condition.
