Vitamin K + Blood Thinners: Warfarin Interaction Risk

Vitamin K directly counteracts warfarin (Coumadin). Keep intake consistent, not zero. Sudden changes affect INR levels. Check your supplement stack.

Vitamin K Overdose Risk

Vitamin K affects blood clotting; high doses can interact with warfarin and similar drugs.

Verified Regional Dose References

StandardRDAUpper Limit (UL)
United States120 mcg1000 mcg
European Union120 mcg1000 mcg
Australia120 mcg1000 mcg

RDA = Recommended Dietary Allowance. UL = Tolerable Upper Intake Level. “Not established” does not mean unlimited intake is safe.

Frequently Asked Questions

Does vitamin K interact with blood thinners?

Yes. Vitamin K directly counteracts warfarin (Coumadin). If you take blood thinners, keep your vitamin K intake consistent day-to-day rather than avoiding it entirely. Sudden changes in vitamin K intake can affect your INR levels. Consult your doctor before taking vitamin K supplements.

Check if Your Vitamin K Intake Is Safe

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Related: Vitamin K full safety profile · Dosage comparison by country

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Reviewed by NutriAudit editorial team. Based on public reference data from NIH ODS, FDA, EFSA, and other cited sources. Not medical advice.

Not medical advice. Always consult a qualified healthcare professional for personal medical decisions.