Supplements and blood thinners: warfarin, Eliquis and Xarelto

September 28, 2026By VitOptics Staff

Can you take vitamin K2, fish oil or other supplements with a blood thinner?

Short answer: it depends on which blood thinner you take, so ask the person who manages it before you start, stop or change any supplement, because some supplements can alter a blood thinner's effect or increase bleeding risk. With warfarin, vitamin K (K1 or K2) changes how well the medicine works, so keep your intake steady, and bring fish oil, vitamin E and herbal products into the same conversation. With Eliquis (apixaban) or Xarelto (rivaroxaban), vitamin K doesn't need to stay steady the way it does with warfarin, but both labels say to avoid St. John's wort, and large doses of vitamin E can add to bleeding risk with any anticoagulant.

Start with the name on your prescription bottle. The question to bring to your next conversation is specific: “Can I take this ingredient, at this amount, with this medicine?”

First, identify your blood thinner

Warfarin (Coumadin, Jantoven) is an anticoagulant. Apixaban (Eliquis), rivaroxaban (Xarelto), dabigatran (Pradaxa) and edoxaban (Savaysa) belong to a newer group called direct oral anticoagulants, often shortened to DOACs. A scientific statement from the American Heart Association explains how these medicines differ from warfarin.

Aspirin and clopidogrel (Plavix) are antiplatelet medicines, another category often described as blood thinners. If one is on your medication list, include it when you ask about supplements.

Ask the pharmacy to explain an unfamiliar medicine name. Avoid choosing a supplement from a general “safe with blood thinners” list without discussing your particular prescription and product with a health professional.

With warfarin, vitamin K consistency matters

Vitamin K helps the body make proteins involved in normal blood clotting. Warfarin works against vitamin K, so changes in vitamin K intake can change warfarin's effect.

Keep the amount of vitamin K you get from food and supplements about the same each day. You don't have to give up vegetables, but avoid sudden large amounts and keep your usual amount steady from week to week. Talk with your care team before making a major dietary change.

Check a proposed multivitamin or combination supplement for vitamin K, including K1 and K2. On a label, vitamin K may appear as phylloquinone or phytonadione (K1), or MK-4 or MK-7 (K2). “D3 + K2”, bone-support and multivitamin products often contain it. A K2 label does not put it outside this discussion.

In one small study of healthy volunteers given a warfarin-type blood thinner (acenocoumarol), even 10 mcg a day of MK-7 lowered INR enough to matter in at least 4 in 10 of them, which means the blood thinner was working less well. This is a reason to bring the full label, rather than rely on the product's name or assume a small amount is harmless.

Vitamin K can appear in more than one product in your routine. Our guide explains how to check for duplicate supplement ingredients, including those in multivitamins.

Ask before stopping a vitamin K supplement as well as before starting one. Stopping one suddenly can raise bleeding risk; starting one can make warfarin less protective against clots. Warfarin monitoring uses a blood test reported as an INR. Ask the clinician managing your warfarin whether a planned change calls for another test.

If you also take allopurinol, our guide to allopurinol and supplements covers what its label says about warfarin.

MedlinePlus's instructions for taking warfarin say not to drink alcohol and list cranberry juice, green tea and herbal teas among items to keep in small, steady amounts.

Know when to get urgent help

After a head injury while taking an anticoagulant, go to an emergency department for assessment, even if you initially feel well. Tell the staff you take a blood thinner, and carry a card or wear a bracelet that says so. Bleeding inside the head can show up hours or days later, so call 911 for a worsening headache, repeated vomiting, confusion, unusual sleepiness, weakness or trouble speaking.

Call 911 for bleeding that won't stop, coughing up or vomiting blood, fainting, confusion, chest pain or discomfort lasting two minutes or more, or trouble breathing.

Call 911 right away for signs of a stroke: one side of the face drooping, one arm drifting down or feeling weak, slurred or strange speech, sudden numbness or weakness (especially on one side), sudden trouble seeing or walking, or a sudden severe headache with no known cause.

Swelling, pain, warmth or redness in one leg or arm can mean a blood clot; see your doctor as soon as possible. Get emergency help right away for sudden trouble breathing, chest pain that gets worse when you breathe in or cough, a fast or irregular heartbeat, or coughing up blood.

Call your doctor right away, or get emergency care, for red, pink or brown urine; red or black tarry stools; vomiting material that looks like coffee grounds; nose or gum bleeding that won't stop; unusual bruising; much heavier periods; or feeling dizzy or faint.

Eliquis, Xarelto and other DOACs: a different check

With a DOAC, you don't need to keep your vitamin K intake steady the way warfarin users do. The American Heart Association scientific statement describes that difference. It does not establish that every supplement is suitable with a DOAC.

The prescribing information for apixaban (Eliquis) says to avoid St. John's wort, because it lowers the amount of medicine in your blood and can reduce its protection against clots.

The prescribing information for rivaroxaban (Xarelto) also says to avoid St. John's wort. If you already take St. John's wort with either medicine, tell your prescriber before you start or stop it.

DOACs do not require routine INR monitoring in the way warfarin does, but supplements and herbs can still affect their blood levels. A 2021 review of DOAC food and supplement interactions advises anyone on an anticoagulant, including dabigatran (Pradaxa) or edoxaban (Savaysa), to avoid products containing St. John's wort. Your doctor may still check your kidney function from time to time. Keep your regular medication reviews and ask about the exact product.

Vitamin E, fish oil, CoQ10 and herbs with blood thinners

Vitamin E: Large supplemental doses can increase bleeding risk when combined with anticoagulant or antiplatelet medicines. NIH says the risk is higher when vitamin K intake is low, and that the amount needed for a clinically important effect is unknown. Ask before taking any vitamin E supplement, and don't treat a dose you read about as a personal safe limit.

Herbal supplements and CoQ10: MedlinePlus lists coenzyme Q10, echinacea, garlic, ginkgo, ginseng, goldenseal and St. John's wort among products that may interact with warfarin. Include each one you use when you discuss your routine.

If you also take a statin and are considering CoQ10, our guide to supplements and statins explains the evidence and what to ask.

Fish oil: NIH notes that high doses can affect platelets and might raise INR in people taking warfarin. Most studies at 3–6 g a day found no significant change, but prescription omega-3 labels still advise periodic INR checks.

MedlinePlus's warfarin instructions list fish oil supplements among products to keep in small, steady amounts. Tell whoever manages your blood thinner before you start, stop or change a fish oil dose.

MedlinePlus's pages for warfarin, apixaban and rivaroxaban all name aspirin and NSAID pain relievers such as ibuprofen (Advil, Motrin) and naproxen (Aleve) among the medicines to tell your doctor or pharmacist about. Ask before taking them.

Bring a record, not just a bottle count

Bring a list of prescriptions, over-the-counter medicines and supplements, including each product's name, amount and timing, plus label photographs. Include occasional products and any planned change: starting, stopping, switching brands or changing an amount. Use our guide to what to review before starting a new supplement to prepare.

Ask before changing your routine

Bring these questions to your pharmacist or doctor:

Is this exact product appropriate with my full medication list?
Should I keep taking my current supplement while you review it?
If we change anything, what follow-up do I need?
Which symptoms should prompt a call?
What should I tell my dentist or surgical team?

NIH recommends professional guidance before combining supplements with prescribed medicines and disclosing supplements before procedures. Write down the agreed plan and who to contact with questions.

Do not stop your prescribed anticoagulant on your own to make room for a supplement. Stopping a blood thinner on your own can raise your risk of a stroke or a blood clot. Follow your prescriber's instructions.

Where VitOptics fits

VitOptics builds a personalized daily supplement pack from a free, three-minute assessment. If you tick the blood-thinner option in its safety screen, or name one anywhere in your answers (warfarin, Eliquis, Xarelto, Pradaxa or Plavix, for example), we never select or offer products with vitamin K, including multivitamins that contain it, or any product on our fixed bleeding-risk list, which includes fish oil and other omega-3s, vitamin E, turmeric, ginger, CoQ10, garlic, ginkgo, ginseng, St. John's wort, melatonin and glucosamine. The exception is daily aspirin on its own: if it is the only one you take and you list it with your medications, nothing is left out because of it. In that aspirin-only case, fish oil and other omega-3s, vitamin E, turmeric, ginger, garlic, ginkgo, ginseng and resveratrol can still be chosen, and each of those carries a note to watch for unusual bruising or bleeding and to tell your prescriber you take that supplement.

Your result says what was left out and why. If you asked for one of these products by name, you may be able to add it after you confirm you've checked with your prescriber, except products with vitamin K, which are never added. A bottle you already take that is on the list stays outside your pack; keep taking or stop it only as your prescriber advises. Everything else is still checked against the medications and conditions you enter, by a second automated check or by a person on our team. Your result lists every formula, the amount of each ingredient and the reason it is there, so review it with the prescriber who manages your blood thinner before you start.

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This article is for educational purposes and is not medical advice. Supplements are not intended to diagnose, treat, cure or prevent any disease.

Prepared with AI assistance using the sources linked in this article.

Last updated: October 23, 2026

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