Drug & supplement interaction

Coenzyme Q10 + Warfarin

Warfarin brand name: Warfarin.

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

Coenzyme Q10 has a moderate interaction with Warfarin. Coenzyme Q10 is chemically similar to menaquinone and might have vitamin K-like procoagulant effects, which could decrease the effects of warfarin.

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

Coenzyme Q10 and Warfarin

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

Moderate

WARFARIN (Coumadin)

Coenzyme Q10 is chemically similar to menaquinone and might have vitamin K-like procoagulant effects, which could decrease the effects of warfarin.
Concomitant use of coenzyme Q10 and warfarin might reduce the anticoagulant effects of warfarin. Four cases of decreased warfarin efficacy thought to be due to coenzyme Q10 have been reported. However, there is some preliminary clinical research that suggests coenzyme Q10 might not significantly decrease the effects of warfarin in patients who have a stable INR.
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

Here's the gist with CoQ10 and warfarin: CoQ10's chemical structure looks a lot like vitamin K, the very nutrient warfarin works against to thin your blood. So in theory, adding CoQ10 could nudge your blood toward clotting again and make warfarin a little less effective. That could show up as a drop in your INR, and in a worst-case situation a higher risk of a clot forming.

I want to keep this in perspective, though. The evidence here is thin, mostly a handful of anecdotal case reports, and some research found no meaningful change in people with a steady INR. Since warfarin is a narrow-margin drug where small shifts matter, please don't start or stop CoQ10 on your own. Just loop in your doctor or pharmacist first so they can check your INR a bit more closely if needed.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Spigset O. Reduced effect of warfarin caused by ubidecarenone. Lancet 1994;334:1372-3. PubMed
  2. Heck AM, DeWitt BA, Lukes AL. Potential interactions between alternative therapies and warfarin. Am J Health Syst Pharm 2000;57:1221-7. DOI
  3. Landbo C, Almdal TP. [Interaction between warfarin and coenzyme Q10]. Ugeskr Laeger 1998;160:3226-7.
  4. Porterfield LM. Why did the response to warfarin change? RN 2000;63:107.
  5. Engelsen J, Nielsen JD, Winther K. Effect of coenzyme Q10 and Ginkgo biloba on warfarin dosage in stable, long-term warfarin treated outpatients. A randomised, double blind, placebo-crossover trial. Thromb Haemost 2002;87:1075-6. DOI

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

Coenzyme Q10 Also Interacts With Other Medications

Coenzyme Q10 has 25 moderate, 172 minor known drug interactions in our database — the Warfarin one above is one of them. If you take anything else, check it against the full list below.

Moderate 25 Minor 172 No known interaction 2,633 (incl. Warfarin)
Taking anything else?

Check Another of Your Medications Against Coenzyme Q10

Covers the 2,830 medications we’ve checked against Coenzyme Q10. Pick one to open its full report.

From our Q&A

Questions About Coenzyme Q10 or Warfarin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Coenzyme Q10 or Warfarin, 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 Warfarin

This page covers Coenzyme Q10 only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Warfarin page lists 361 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Alfalfa (major), American Ginseng (major), Beer (major) and Cannabis (major).

By severity: 16 major · 301 moderate · 44 minor.

From our pharmacist’s overview on the Warfarin page

“People take warfarin to prevent dangerous clots, and many are the same people reaching for glucosamine for sore joints or a multivitamin containing vitamin K, which makes this a list that deserves genuine respect. Of the 361 supplements on file for warfarin, 16 carry a major rating, and the danger runs in both directions: some add to w…”

Reviewed by 2 · Jul 18, 2026

Open the Warfarin interaction page

One more smart check

Taking Coenzyme Q10 as Part of a Dietary Supplement Product? Check It for Interactions

We hold 6,926 real supplement products containing Coenzyme Q10, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Coenzyme Q10. Your product may carry other ingredients that interact with Warfarin too, on top of Coenzyme Q10 — 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 Coenzyme Q10 and Warfarin 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 Coenzyme Q10
Top 5%

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

29 days ago today
Medication Warfarin
Top 10

#4 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 Coenzyme Q10

What is Coenzyme Q10?

  • Heart health
  • Statin-related muscle aches
  • Migraine prevention
  • Energy and fatigue
  • Aging and antioxidant support

CoQ10 is a vitamin-like substance your body makes naturally that helps cells produce energy and acts as an antioxidant. It is generally well tolerated and is most studied for heart conditions, statin-related muscle symptoms, and migraine prevention, though the strength of the evidence varies. Talk with your pharmacist or doctor before starting it, especially if you take heart or blood pressure medicines.

Read the full Coenzyme Q10 monograph & all interactions
Medication

About Warfarin

What Is Warfarin Used For?

Brand name: Warfarin

Warfarin sodium tablets and Jantoven tablets are both used to prevent and treat venous thrombosis (blood clots in the veins) and pulmonary embolism (a clot in the lungs). They are also used to prevent clot-related complications in people with atrial fibrillation (an irregular heart rhythm) or who have had a heart valve replaced.

In people who have had a heart attack, warfarin is used to reduce the risk of death, another heart attack, stroke, or other clotting events. It does not dissolve an existing clot, but it helps prevent the clot from growing and stops new dangerous clots from forming.

See full Warfarin drug information
Keep checking

Other Drugs & Coenzyme Q10

Browse every other medication we’ve checked against Coenzyme Q10 — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
25Moderate
172Minor
2,632No known interaction
25 Moderate 172 Minor 2,632 No interaction
Moderate

25 interactions

Minor

172 interactions

Showing 60 of 172 minor interactions — see all 172 on the Coenzyme Q10 page.

No interaction 2,632 drugs checked — show the list

We also checked Coenzyme Q10 against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,632 medications checked with no known interaction — see the full Coenzyme Q10 list.

See the full Coenzyme Q10 interactions page
See every supplement checked against Warfarin, 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
Coenzyme Q10 monograph › Uses, safety, and every drug interaction in one place Warfarin supplement interactions › Every supplement checked against Warfarin, ranked by severity Warfarin 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 Coenzyme Q10 and Warfarin Together: Common Questions

Can you take Coenzyme Q10 with Warfarin?
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 Coenzyme Q10 and Warfarin 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 Warfarin and Coenzyme Q10?

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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.