This article is for informational purposes only and does not replace medical advice. Consult your doctor or pharmacist before starting, stopping, or changing any supplement while on blood thinners.
Several common supplements increase bleeding risk when combined with blood thinners like warfarin, Eliquis, or Xarelto. The biggest ones to watch: fish oil at high doses, vitamin E above 400 IU, ginkgo biloba, garlic supplements, turmeric/curcumin, and St. John's Wort. Some supplements are perfectly safe. The key is knowing which category yours falls into before you start taking them together.
Why blood thinners and supplements interact
Blood thinners work by slowing your body's clotting process. Warfarin blocks vitamin K, which your body needs to form clots. Newer blood thinners like Eliquis (apixaban) and Xarelto (rivaroxaban) inhibit specific clotting factors directly. Plavix (clopidogrel) prevents platelets from sticking together.
Any supplement that also thins the blood, interferes with clotting factors, or changes how your body processes these drugs can tip the balance. The result: either too much blood thinning (bleeding risk) or too little (clotting risk).
This is not a "maybe it matters" situation. Supplement-blood thinner interactions send people to the emergency room. The National Institutes of Health and the NIH Office of Dietary Supplements both flag supplement-drug interactions as a serious concern.
Supplements to avoid or use with extreme caution
These supplements have documented interactions with blood thinners. Either avoid them entirely or use only under direct medical supervision.
Fish oil / omega-3 fatty acids
Fish oil has its own antiplatelet effect, and the honest version is more mixed than most lists suggest. The NIH Office of Dietary Supplements says doses of 2 to 15 g/day of EPA and/or DHA might increase bleeding time by reducing platelet aggregation, and that fish oil might prolong clotting times when taken with warfarin. The same fact sheet then reports that most research indicates doses of 3 to 6 g/day do not significantly affect the anticoagulant status of patients taking warfarin, and that a 2014 review concluded omega-3s do not affect the risk of clinically significant bleeding. What it does not drop is monitoring: FDA-approved package inserts for omega-3 medicines say patients taking them with anticoagulants should be monitored periodically for changes in INR. Treat fish oil as something to clear with your doctor or pharmacist, and report any unusual bruising.
For timing details on fish oil specifically, see our guide on fish oil: morning or night.
Vitamin E (above 400 IU)
Vitamin E inhibits platelet aggregation. At standard multivitamin doses (30 IU), this is not a concern. At supplemental doses above 400 IU, the antiplatelet effect is strong enough to add meaningful bleeding risk on top of your blood thinner. A meta-analysis in the Annals of Internal Medicine also linked high-dose vitamin E to increased all-cause mortality. Unless your doctor has specifically prescribed high-dose vitamin E, keep it under 400 IU.
Ginkgo biloba
Ginkgo is one of the most well-documented supplement risks for blood thinner users. It inhibits platelet-activating factor (PAF), which means it directly interferes with blood clotting. Case reports have linked ginkgo to spontaneous bleeding events, including subdural hematoma, in patients on anticoagulants. Avoid ginkgo entirely while on any blood thinner.
Garlic supplements (concentrated)
Regular food-quantity garlic in cooking is fine. Concentrated garlic supplements (allicin extract, aged garlic) are a different story. They inhibit platelet aggregation and may increase the activity of blood thinners. The National Center for Complementary and Integrative Health specifically warns about garlic supplement interactions with anticoagulants.
Turmeric / curcumin (high-dose supplements)
A 1985 brief communication in Thrombosis Research reported an antithrombotic effect of curcumin. That is a preclinical finding rather than a trial in people taking anticoagulants, so it shows a mechanism, not a measured bleeding risk. NCCIH says conventionally formulated oral turmeric or curcumin is likely safe in the recommended amounts for up to 2 or 3 months, and does not list an anticoagulant interaction. Turmeric in food is a different thing from a concentrated curcumin capsule, and the concentrated form is the one to raise with your doctor or pharmacist before adding it to a blood thinner.
Other supplements to avoid
- Ginger supplements (concentrated capsules, not kitchen ginger): mild antiplatelet effect
- Dong quai: contains coumarins that can potentiate warfarin
- Feverfew: inhibits platelet aggregation
- St. John's Wort: does not increase bleeding directly, but it induces liver enzymes that can dramatically reduce the effectiveness of warfarin, Eliquis, and Xarelto. This is equally dangerous in the opposite direction: your blood thinner may stop working.
Pillo includes a Drug-Drug Interaction Checker that lets you plug in your blood thinner and each supplement to see flagged interactions before you buy anything new.
The warfarin-specific vitamin K rule
If you take warfarin, vitamin K deserves its own section because the interaction is unique and widely misunderstood.
You do not need to avoid vitamin K. You need to keep your vitamin K intake consistent from day to day.
Warfarin works by blocking vitamin K's role in the clotting process. Your doctor sets your warfarin dose based on your typical vitamin K intake. If you suddenly eat a large salad or start a vitamin K supplement, your INR drops and your blood thickens. If you suddenly stop eating greens, your INR rises and your bleeding risk increases.
The fix: eat roughly the same amount of vitamin K-rich foods each week. Do not start or stop vitamin K supplements without telling your doctor. Do not go on a kale binge one week and then eat no greens the next.
This rule does not apply to Eliquis, Xarelto, or Plavix. Those drugs do not interact with vitamin K.
For more on vitamin K interactions, see our guide on vitamin D and K2 together, which covers when K2 supplementation makes sense and when it does not.
CoQ10 and warfarin
CoQ10 (ubiquinone) has a chemical structure similar to vitamin K2. Several case reports suggest it can reduce warfarin's effectiveness, lowering your INR. If you take warfarin and want to add CoQ10, tell your doctor so they can monitor your INR more closely during the transition. This interaction is less of a concern with Eliquis or Xarelto.
What the warfarin vitamin K rule does not mean for Eliquis or Xarelto
The rule above is a warfarin rule. If your blood thinner is Eliquis (apixaban) or Xarelto (rivaroxaban), it is not your rule, and both labels say why.
Both drugs are factor Xa inhibitors. Warfarin works by interfering with vitamin K's role in clotting; these two do not. Each label states it plainly in its bleeding section: protamine sulfate and vitamin K "are not expected to affect the anticoagulant activity of apixaban", and the Xarelto label says the same for rivaroxaban. Those sentences describe vitamin K given as an emergency reversal agent rather than vitamin K on your dinner plate, but the underlying point is the one you came for: the effect of these drugs does not run through vitamin K.
There is a second difference that matters more than most people realize. On warfarin, the INR blood test is your safety net, so if a supplement nudges your clotting, a lab draw can catch it. On Eliquis, the label takes that net away: monitoring "using a clotting test (PT, INR, or aPTT) or anti-factor Xa (FXa) activity is not useful and is not recommended". The familiar advice to watch your INR after adding a supplement has nothing to watch here. That is a reason to be more careful about what you add, not less.
The labels do name one supplement, and it runs in the opposite direction from what most people assume: St. John's wort. Both list it among the enzyme inducers to avoid because it lowers how much drug reaches your bloodstream. The risk there is a clot, not a bleed.
Can you take magnesium with Eliquis?
Neither label lists a magnesium supplement as an interaction. Magnesium shows up in both only as magnesium stearate, an inactive ingredient in the tablet itself. The closest thing to a test sits in the Xarelto label's pharmacology section, where an antacid containing aluminum hydroxide and magnesium hydroxide "did not show an effect on the bioavailability and exposure of rivaroxaban". That was an antacid, not a magnesium supplement, so treat it as a hint rather than an answer. NIH's Office of Dietary Supplements lists magnesium's medication interactions as oral bisphosphonates, tetracyclines, and quinolone antibiotics, plus diuretics and proton pump inhibitors that can affect magnesium status. Anticoagulants are not on that list. Not listed is not the same as studied and cleared, so tell your prescriber before you start.
Can you take fish oil with Eliquis?
Neither label names fish oil or omega-3s. The Office of Dietary Supplements says fish oil "can have antiplatelet effects at high doses, although it appears to be less potent than aspirin", and notes that the authors of a 2014 review "concluded that omega-3s do not affect the risk of clinically significant bleeding". The catch is that this guidance is written around warfarin, where the follow-up step is to recheck your INR. On Eliquis there is no INR to recheck. The dose-related picture is in the fish oil section above.
Can you take vitamin D with Eliquis?
Neither label names vitamin D. The Office of Dietary Supplements lists vitamin D's medication interactions as orlistat, statins, steroids, and thiazide diuretics, and anticoagulants are absent from that list. The version people actually ask about is a combined D3 + K2 product, and per the label sentence above, the K2 half is not expected to change how Eliquis works, which is the reverse of the warfarin situation. Our guide on vitamin D and K2 together covers when the combination makes sense.
None of this replaces a check with the person who prescribed your blood thinner. Consult your doctor or pharmacist for advice specific to your medications.
Supplements that are generally safe with blood thinners
Not everything is off-limits. These supplements have no significant known interactions with common blood thinners:
| Supplement | Notes |
|---|---|
| Vitamin D | Safe at standard doses. No clotting interaction. See can you take too much vitamin D for dosing guidance. |
| Calcium | Safe. No blood thinner interaction. |
| Magnesium | Safe at normal doses. Very high doses may have a mild additive effect. See best time to take magnesium. |
| B vitamins (B6, B12, folate) | Safe. May help lower homocysteine, which is good for cardiovascular health. |
| Iron | Safe. No clotting interaction. Timing matters for absorption though. See iron supplement timing. |
| Probiotics | Safe. No known blood thinner interaction. |
| Vitamin C (under 1,000 mg) | Safe at moderate doses. Very high doses (2,000+ mg) may theoretically affect warfarin, but standard supplementation is fine. |
Quick reference: the full interaction chart
| Supplement | Risk level | Interaction type | Blood thinners affected |
|---|---|---|---|
| Fish oil (high dose) | Moderate | Adds blood-thinning effect | All |
| Vitamin E (>400 IU) | Moderate to high | Inhibits platelet aggregation | All |
| Ginkgo biloba | High | Blocks platelet-activating factor | All |
| Garlic supplements | Moderate | Inhibits platelet aggregation | All |
| Turmeric/curcumin | Moderate | Antiplatelet + anticoagulant | All |
| Ginger supplements | Low to moderate | Mild antiplatelet effect | All |
| Dong quai | High (warfarin) | Contains coumarins | Warfarin especially |
| Feverfew | Moderate | Inhibits platelet aggregation | All |
| St. John's Wort | High | Reduces drug effectiveness | Warfarin, Eliquis, Xarelto |
| CoQ10 | Moderate (warfarin) | May reduce warfarin effect | Warfarin |
| Vitamin K | Context-dependent | Consistency matters | Warfarin only |
| Vitamin D, calcium, magnesium, B vitamins, iron | Low | No significant interaction | None |
If you are managing blood thinners plus supplements, setting separate timed reminders helps you keep everything spaced correctly. Pillo's persistent alarm keeps going until you confirm each dose, which prevents the kind of "did I already take that?" confusion that gets risky with anticoagulants.
What to do before adding any supplement
- Tell your doctor or pharmacist. This is not optional with blood thinners. Bring the bottle or show them the exact product.
- Check the interaction. Ask your pharmacist to screen your supplement against your blood thinner before purchasing.
- Start low. If your doctor approves a supplement, begin at the lowest dose and monitor for bruising, bleeding gums, or prolonged cuts.
- Watch your INR (warfarin users). Any new supplement warrants an INR check 1 to 2 weeks after starting.
- Do not stop supplements suddenly. If you have been taking vitamin K or another supplement regularly, stopping abruptly can shift your clotting balance just as much as starting something new.
If you also take a statin, the list is different again. We cover which supplements to avoid with statins, and the milligram threshold that decides it, in a separate guide.
FAQ
Can I take fish oil with Eliquis?
The NIH Office of Dietary Supplements says fish oil can have antiplatelet effects at high doses and might prolong clotting times when taken with warfarin. The same fact sheet also reports that most research indicates doses of 3 to 6 g/day do not significantly affect the anticoagulant status of patients taking warfarin, and that a 2014 review concluded omega-3s do not affect the risk of clinically significant bleeding. What it keeps is a monitoring instruction: FDA-approved package inserts for omega-3 medicines say patients taking them with anticoagulants should be monitored periodically for changes in INR. That instruction was written around warfarin, and as the Eliquis section above explains, INR is not a useful test on Eliquis. Tell your doctor or pharmacist before combining them.
Is turmeric safe with warfarin?
Turmeric in food (curries, golden milk with a pinch of turmeric) is a different question from a concentrated curcumin capsule. The evidence for an anticoagulant interaction is a 1985 preclinical antithrombotic finding rather than a trial in people taking warfarin, and NCCIH does not list an anticoagulant interaction for turmeric. That is not the same as cleared, so a concentrated curcumin supplement is one to raise with your doctor or pharmacist rather than add on your own. The picture changes when the other drug is an anti-inflammatory rather than a blood thinner, which is what turmeric and meloxicam works through.
Do I need to avoid all vitamin K on warfarin?
No. The goal is consistency, not avoidance. Eat roughly the same amount of vitamin K each week. Sudden increases or decreases in vitamin K intake will affect your INR and make your warfarin dose unreliable. Do not start or stop K supplements without talking to your doctor.
Can I take magnesium with blood thinners?
Neither the Eliquis nor the Xarelto label lists a magnesium supplement as an interaction, and the NIH Office of Dietary Supplements fact sheet on magnesium names oral bisphosphonates, tetracyclines, quinolone antibiotics, diuretics and proton pump inhibitors as the medication interactions to know, without naming anticoagulants. Not listed is not the same as studied and cleared, so raise it with your doctor or pharmacist before you start. See our full guide on magnesium timing.
Can I take magnesium with Eliquis?
The Eliquis label does not list a magnesium supplement as an interaction, and magnesium appears in it only as magnesium stearate, an inactive tablet ingredient. NIH's Office of Dietary Supplements names oral bisphosphonates, tetracyclines, quinolone antibiotics, diuretics, and proton pump inhibitors as magnesium's medication interactions, and anticoagulants are not among them. Because Eliquis is not monitored with INR, there is no routine blood test that would flag a problem, so tell your prescriber or pharmacist before starting magnesium.
What about a daily multivitamin?
Most standard multivitamins are safe with blood thinners. The vitamin K content is usually small and consistent (50 to 80 mcg), which is fine for warfarin users as long as you take the same multivitamin daily. Check the label for vitamin E content and make sure it is under 400 IU. Avoid multivitamins with added herbal blends that may include ginkgo, garlic, or ginger extracts.
Should I stop all supplements before surgery?
Most surgeons ask patients to stop supplements with blood-thinning effects (fish oil, vitamin E, ginkgo, garlic, turmeric) 7 to 14 days before surgery. Your blood thinner management around surgery is a separate decision your doctor will handle. Always provide a complete list of everything you take, including supplements.
Related guides:
- Supplement timing chart: when to take each vitamin
- Which vitamins should not be taken together
- Fish oil: morning or night?
- Best time to take magnesium
- Can you take too much vitamin D?
- Missed dose of Eliquis
- Missed dose of warfarin
- Missed dose of Xarelto
- Missed blood thinner and stroke risk
- Supplements and antidepressants: which mix safely
If remembering doses is the hard part, the Pillo medication reminder app can take that job off your plate.
This article is for informational purposes only. It is not medical advice. Consult your doctor or pharmacist before starting, stopping, or changing any supplement while taking blood thinners.
Reviewed under our Medical Review Policy.
