Drug & supplement interaction

Krill Oil + Heparin

Heparin brand name: Heparin.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Krill Oil has a moderate interaction with Heparin. Theoretically, krill oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Krill Oil and Heparin

Here is the interaction we found between these two, with the evidence behind it.

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

Why this applies to Heparin

Heparin falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Krill Oil interacts with.

Theoretically, krill oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Taking high doses of omega-3 fatty acids from fish oil can modestly decrease platelet aggregation. Since krill oil also contains these fatty acids, taking high doses of krill oil might also inhibit platelet aggregation. Theoretically, taking high doses of krill oil with antiplatelet or anticoagulant drugs might increase the risk of bleeding. However, the omega-3 content of krill oil is much lower than that of fish oil.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Heparin already does one big job: it thins your blood to keep clots from forming. Krill oil brings omega-3 fats (EPA and DHA) that, in high amounts, can make your platelets a little less sticky. Stack those two together and the concern is simply additive. You could, in theory, bruise more easily or bleed a bit longer from a cut, a nosebleed, or bleeding gums.

Here's the honest part: this is a theoretical worry based on how these fats behave, not strong proof. Krill oil also has far less omega-3 than regular fish oil, so the effect is usually small. Still, because heparin is a powerful blood thinner often used in hospital settings, it's worth a quick word with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Leaf A. On the reanalysis of the GISSI-Prevenzione. Circulation 2002;105:1874-5. PubMed
  2. Connor WE. n-3 Fatty acids from fish and fish oil: panacea or nostrum? Am J Clin Nutr 2001;74;415-6. PubMed
  3. Calder PC. N-3 polyunsaturated fatty acids, inflammation and immunity: pouring oil on troubled waters or another fishy tale? Nutr Res 2001;21:309-41. DOI
  4. Harris WS, Miller M, Tighe AP, et al. Omega-3 fatty acids and coronary heart disease risk: clinical and mechanistic perspectives. Atherosclerosis 2008;197:12-24. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Krill Oil Also Interacts With Other Medications

Krill Oil has 207 moderate known drug interactions in our database — the Heparin one above is one of them. If you take anything else, check it against the full list below.

Moderate 207 No known interaction 2,623 (incl. Heparin)
Taking anything else?

Check Another of Your Medications Against Krill Oil

Covers the 2,830 medications we’ve checked against Krill Oil. Pick one to open its full report.

From our Q&A

Questions About Krill Oil or Heparin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Krill Oil or Heparin, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Heparin

This page covers Krill Oil only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Heparin page lists 202 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Danshen (major), Piracetam (major), Aconite (moderate), Allspice (moderate) and Aloe (moderate).

By severity: 2 major · 183 moderate · 17 minor.

From our pharmacist’s overview on the Heparin page

“Heparin exists to keep clots from forming, and all 202 supplements on this list touch that same clotting machinery, so treat these pairings with real care. Nearly all lean the same way, adding antiplatelet or anticoagulant activity that can push a therapeutic dose toward bruising and bleeding.”

Reviewed by 2 · Jul 18, 2026

Open the Heparin interaction page

One more smart check

Taking Krill Oil as Part of a Dietary Supplement Product? Check It for Interactions

We hold 605 real supplement products containing Krill Oil, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Krill Oil. Your product may carry other ingredients that interact with Heparin too, on top of Krill Oil — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Krill Oil and Heparin Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Krill Oil
Top 25%

#356 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Heparin
Steady interest

#1,608 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Krill Oil

What is Krill Oil?

Krill Oil
  • Heart and cholesterol support
  • High triglycerides
  • Joint pain and inflammation
  • Brain and eye health
  • PMS symptoms
  • General omega-3 supplementation

Krill oil is a source of omega-3 fatty acids (EPA and DHA) bound to phospholipids, which may help absorption. It is most studied for lowering triglycerides and supporting heart health, but the evidence for many other uses is limited. It is generally well tolerated, but people with shellfish allergy should avoid it, and anyone pregnant, breastfeeding, or on blood thinners should check with a pharmacist or doctor first.

Read the full Krill Oil monograph & all interactions
Medication

About Heparin Injection

What Is Heparin Injection Used For?

Brand name: Heparin

Heparin Sodium Injection is used to prevent and treat venous thrombosis (blood clots in veins) and pulmonary embolism (clots in the lungs). It is also used to prevent blood clots after major abdominothoracic surgery, to manage atrial fibrillation with embolization (a heart rhythm problem that can cause clots), and to treat disseminated intravascular coagulation (DIC), a serious condition where the blood clots too much throughout the body.

Additional uses include preventing clotting during arterial and cardiac surgery, treating peripheral arterial embolism (clots in the arteries of the limbs), and serving as an anticoagulant during blood transfusions, dialysis, and procedures using extracorporeal circulation (machines that temporarily take over heart or lung function).

See full Heparin Injection drug information
Keep checking

Other Drugs & Krill Oil

Browse every other medication we’ve checked against Krill Oil — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
207Moderate
0Minor
2,622No known interaction
207 Moderate 2,622 No interaction
Moderate

207 interactions

Showing 60 of 207 moderate interactions — see all 207 on the Krill Oil page.

No interaction 2,622 drugs checked — show the list

We also checked Krill Oil against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,622 medications checked with no known interaction — see the full Krill Oil list.

See the full Krill Oil interactions page
See every supplement checked against Heparin, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Krill Oil monograph › Uses, safety, and every drug interaction in one place Heparin supplement interactions › Every supplement checked against Heparin, ranked by severity Heparin Injection drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Krill Oil and Heparin Together: Common Questions

Can you take Krill Oil with Heparin?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Krill Oil and Heparin interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Heparin and Krill Oil?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.