Can You Take Cod Liver Oil With Rivaroxaban (Xarelto)?

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Cod liver oil and rivaroxaban (brand name Xarelto) do have a documented moderate interaction, though it's largely theoretical at typical supplement doses.

Many people do take the two together without problems, but because rivaroxaban is a blood thinner and cod liver oil may have a mild blood-thinning effect of its own, this is a combination you'll want to run by your doctor or pharmacist rather than start on your own.

Why Cod Liver Oil May Add to Bleeding Risk

Cod liver oil comes from the liver of the Atlantic cod and is a rich source of the omega-3 fatty acids EPA and DHA, along with vitamins A and D. Omega-3s can make platelets, the cell fragments that help your blood clot, a little less 'sticky.'

Since rivaroxaban already reduces clotting by blocking factor Xa, one of the key proteins in the clotting cascade, the concern is that the two effects could stack and increase your risk of bleeding.

It's worth noting, though, that the studies raising this concern used quite large amounts. High doses of cod liver oil, in the range of 20 to 40 mL daily (roughly 4 to 8 teaspoons), have been associated with prolonged bleeding time and reduced platelet aggregation in healthy volunteers. Most cod liver oil supplements provide around one teaspoon (about 5 mL) or a capsule or two per day, which is well below the doses studied.

What the Research Actually Shows

The human data here are genuinely mixed, which is why this interaction is considered theoretical rather than proven.

In one study of patients taking 30 mL of cod liver oil daily for six weeks, researchers found reduced collagen-induced platelet aggregation, yet the primary bleeding time was not significantly prolonged.

Studies of DHA on its own paint an even more reassuring picture; one controlled trial that gave healthy men 6 grams of DHA daily for 90 days found it produced no observable changes in blood coagulation, platelet function, or thrombotic tendencies.

Other research suggests DHA may modestly reduce platelet clumping in certain patients, so the effect isn't zero, but at everyday supplement doses it appears to be small.

What to Watch for If You Take Them Together

If your doctor is on board with the combination, stay alert for any signs of increased bleeding, especially in the first few weeks. That includes easy or unusual bruising, nosebleeds, bleeding gums, cuts that take longer than usual to stop, or blood in the urine or stool. Any of those warrant a prompt call to your doctor. It also helps to keep your cod liver oil dose consistent from day to day rather than varying it.

Final Words

To sum up, cod liver oil and rivaroxaban have a moderate but mostly theoretical bleeding-risk interaction, and typical supplement doses are far below the amounts linked to measurable effects in studies.

Since you're on a blood thinner, check in with your doctor or pharmacist before adding it so they can weigh it against your personal bleeding risk.

Feel free to reach back out if any other questions come up; we're always happy to help!