Drug & supplement interaction

Algal Oil + Heparin

Heparin brand name: Heparin.

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

Algal Oil has a minor interaction with Heparin. Theoretically, algal oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

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

Algal Oil and Heparin

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

Minor

ANTICOAGULANT/ANTIPLATELET DRUGS

Why this applies to Heparin

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

Theoretically, algal oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
The risk of interaction is highest for algal oil containing high amounts (> 2 grams daily) of eicosapentaenoic acid (EPA), or EPA and docosahexaenoic acid (DHA). High doses of EPA or oils containing EPA and DHA can reduce platelet aggregation in humans. However, most algal oil contains very little EPA and larger amounts of DHA. While some conflicting evidence exist, most research shows that DHA alone does not affect blood clotting.
Severity Minor Likelihood Unlikely Evidence D

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

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

Heparin is already a powerful blood thinner, so it makes sense to wonder whether adding algal oil tips you toward easier bleeding. The honest answer is that this concern is mostly theoretical, based on how omega-3 fats behave, not on strong real-world reports. At high doses (over about 2 grams a day) the EPA form of omega-3 can make platelets a little less sticky. But most algal oil is rich in DHA and contains very little EPA, and DHA on its own does not appear to meaningfully affect clotting.

So for the typical algal oil product, the added bleeding risk with heparin is small and unlikely. Still, since heparin itself thins your blood, it's smart to mention your supplement to your pharmacist or doctor and watch for easy bruising, nosebleeds, or bleeding that's slow to stop.

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. Terano T, Hirai A, Hamazaki T, et al. Effect of oral administration of highly purified eicosapentaenoic acid on platelet function, blood viscosity and red cell deformability in healthy human subjects. Atherosclerosis 1983;46:321-31.. PubMed
  5. Leng GC, Smith FB, Fowkes FG, et al. Relationship between plasma essential fatty acids and smoking, serum lipids, blood pressure and haemostatic and rheological factors. Prostaglandins Leukot Essent Fatty Acids 1994;51:101-8. PubMed
  6. Nelson GJ, Schmidt PS, Bartolini GL, et al. The effect of dietary docosahexaenoic acid on platelet function, platelet fatty acid composition, and blood coagulation in humans. Lipids 1997;32:1129-36. PubMed
  7. Svaneborg N, Kristensen SD, Hansen LM, et al. The acute and short-time effect of supplementation with the combination of n-3 fatty acids and acetylsalicylic acid on platelet function and plasma lipids. Thromb Res 2002;105:311-6. PubMed
  8. von Houwelingen R, Nordøy A, van der Beek E, et al. Effect of a moderate fish intake on blood pressure, bleeding time, hematology, and clinical chemistry in healthy males. Am J Clin Nutr. 1987 Sep;46(3):424-36. PubMed
  9. Goodnight SH Jr, Harris WS, Connor WE. The effects of dietary omega 3 fatty acids on platelet composition and function in man: a prospective, controlled study. Blood. 1981 Nov;58(5):880-5. DOI
  10. Woodman, R. J., Mori, T. A., Burke, V., Puddey, I. B., Barden, A., Watts, G. F., and Beilin, L. J. Effects of purified eicosapentaenoic acid and docosahexaenoic acid on platelet, fibrinolytic and vascular function in hypertensive type 2 diabetic patients PubMed
  11. Zucker, M. L., Bilyeu, D. S., Helmkamp, G. M., Harris, W. S., and Dujovne, C. A. Effects of dietary fish oil on platelet function and plasma lipids in hyperlipoproteinemic and normal subjects. Atherosclerosis 1988;73(1):13-22. 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

Algal Oil Also Interacts With Other Medications

Algal Oil has 258 moderate, 116 minor 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 258 Minor 116 No known interaction 2,456 (incl. Heparin)
Taking anything else?

Check Another of Your Medications Against Algal Oil

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

Everything else you take

See Every Supplement That Interacts With Heparin

This page covers Algal 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 Algal Oil as Part of a Dietary Supplement Product? Check It for Interactions

We hold 188 real supplement products containing Algal Oil, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Algal Oil. Your product may carry other ingredients that interact with Heparin too, on top of Algal 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 Algal 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 Algal Oil
Top 25%

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

29 days ago today
Medication Heparin
Steady interest

#1,596 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 Algal Oil

What is Algal Oil?

Algal Oil
  • Vegan/vegetarian source of omega-3s (DHA and EPA)
  • Heart and triglyceride health
  • Brain and eye support
  • Pregnancy and infant nutrition
  • General anti-inflammatory support

Algal oil is a plant-based source of the omega-3 fats DHA and (in some products) EPA, making it a popular alternative to fish oil for vegetarians, vegans, and people who dislike fish. There is reasonable evidence that omega-3s can lower triglycerides and support heart and brain health, though more research is needed for many specific uses. It is generally well tolerated, but check with your pharmacist or doctor before starting, especially if you take blood thinners or are pregnant.

Read the full Algal 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 & Algal Oil

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

0Major
258Moderate
116Minor
2,455No known interaction
258 Moderate 116 Minor 2,455 No interaction
Moderate

258 interactions

Showing 60 of 258 moderate interactions — see all 258 on the Algal Oil page.

Minor

116 interactions

Showing 60 of 116 minor interactions — see all 116 on the Algal Oil page.

No interaction 2,455 drugs checked — show the list

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

Showing the 60 most looked-up of 2,455 medications checked with no known interaction — see the full Algal Oil list.

See the full Algal 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
Algal 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 Algal Oil and Heparin Together: Common Questions

Can you take Algal Oil with Heparin?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Algal Oil and Heparin interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Heparin and Algal 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.