Fish Oil vs Krill Oil

Supplement Science Editorial Team·Evidence-Based Supplement Research

Published Apr 1, 2026

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Fish oil is the better value for most people, offering higher EPA/DHA doses at a lower cost with decades of clinical...

Head-to-Head Comparison

Criteria	Fish Oil	Krill Oil	Winner
Bioavailability	Good — triglyceride form, well-absorbed with fat	Superior — phospholipid-bound, absorbed without fat	Krill Oil
Clinical Evidence	Extensive — thousands of RCTs across cardiovascular, brain, and joint health	Growing — dozens of studies, mostly small	Fish Oil
GI Tolerability	Moderate — fishy burps and aftertaste are common complaints	Excellent — phospholipid form rarely causes reflux	Krill Oil
Cost	$0.05-0.15 per gram of EPA+DHA	$0.30-0.60 per gram of EPA+DHA	Fish Oil
Phospholipid vs Triglyceride Form	Triglyceride form — requires bile salts for emulsification	Phospholipid form — self-emulsifying, plus astaxanthin antioxidant	Krill Oil

Detailed Analysis

Bioavailability

Krill oil omega-3s are bound to phospholipids, which integrate directly into cell membranes and are absorbed more efficiently than the triglyceride form in fish oil.

Clinical Evidence

Fish oil has decades of large-scale clinical trials including REDUCE-IT and VITAL. Krill oil research is promising but limited to smaller studies.

GI Tolerability

Krill oil's phospholipid structure mixes with stomach contents more readily, virtually eliminating the fishy burps that plague many fish oil users.

Cost

Fish oil delivers 3-5x more EPA+DHA per dollar. Krill oil capsules contain lower omega-3 concentrations, so you need more capsules to match a fish oil dose.

Phospholipid vs Triglyceride Form

Krill oil's phospholipid-bound omega-3s are structurally identical to cell membrane fatty acids, enabling more direct incorporation. The naturally occurring astaxanthin also protects against oxidation.

Our Verdict

Fish oil wins for most people on cost, dose flexibility, and evidence depth. Choose krill oil if you value absorption efficiency, hate fishy burps, or want the added astaxanthin antioxidant.

Frequently Asked Questions

Can I take fish oil and krill oil together?

Yes, taking both is safe and some people combine them to get the high-dose EPA/DHA from fish oil with the phospholipid delivery and astaxanthin from krill oil. Keep total omega-3 intake under 3g EPA+DHA daily unless directed by a physician, as higher doses may increase bleeding risk.

Which is better for heart health?

Fish oil has stronger evidence for heart health. The REDUCE-IT trial showed high-dose EPA (icosapent ethyl) reduced cardiovascular events by 25%. No krill oil trial has demonstrated comparable outcomes at scale, though krill oil does improve lipid markers in smaller studies.

Is krill oil worth the extra cost?

For most healthy adults, fish oil provides excellent value. Krill oil is worth the premium if you experience fishy burps with fish oil, prefer a smaller capsule, or want the antioxidant benefits of astaxanthin. The absorption advantage may also matter if you take omega-3s without a fatty meal.

Is krill oil more sustainable than fish oil?

Antarctic krill harvesting is managed by CCAMLR and takes less than 1% of estimated biomass, but krill are a keystone species for marine ecosystems. Fish oil sustainability varies widely by source. Look for MSC-certified fish oil or AKER-sourced krill oil for the best environmental standards.

References

Ulven SM, Kirkhus B, Lamglait A (2011). Metabolic effects of krill oil are essentially similar to those of fish oil but at lower dose of EPA and DHA, in healthy volunteers. Lipids. DOI PubMed
Bhatt DL, Steg PG, Miller M (2019). Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia (REDUCE-IT). New England Journal of Medicine. DOI PubMed