Supplement stacks / St Johns Wort + Warfarin
Can You Take St Johns Wort with Warfarin?
St. John's Wort is known to interact with warfarin, potentially reducing its effectiveness and increasing the risk of thromboembolic events. Caution is advised when considering the use of St. John's Wort while on warfarin therapy.
Conservative, AI-assisted reading of publicly available medical sources (NIH, Mayo Clinic, WebMD, Examine.com). Informational only — it can't account for your medications, conditions, or genetics.
St. John's Wort may induce cytochrome P450 enzymes, leading to decreased warfarin levels and increased risk of clotting.
Generally considered safe for short-term use, but can interact with many medications, including warfarin.
Typical dosage: 300 mg three times daily of standardized extract
- photosensitivity
- gastrointestinal upset
- fatigue
- Avoid use with warfarin; consult healthcare provider before use.
- May cause serotonin syndrome when combined with other serotonergic agents.
Warfarin is an anticoagulant that requires careful monitoring of INR levels to prevent bleeding complications.
Typical dosage: 2-10 mg daily, adjusted based on INR results
- bleeding
- bruising
- gastrointestinal upset
- Monitor INR more frequently when starting or stopping St. John's Wort.
- Maintain consistent vitamin K intake.
These come up in questions about this combination — they are not part of the pair above.
Vitamin K
Essential for blood clotting; can counteract the effects of warfarin.
Typical dosage: 90-120 mcg daily for adults
- rare allergic reactions
- Keep intake consistent while on warfarin to avoid fluctuations in INR.
- Consult healthcare provider for dietary sources.
Omega-3 Fatty Acids
Generally safe; may have mild anticoagulant effects.
Typical dosage: 1000-3000 mg daily
- fishy aftertaste
- gastrointestinal discomfort
- Monitor for increased bleeding risk when combined with warfarin.
- Consult healthcare provider before starting.
Coenzyme Q10
Generally safe; may have a mild effect on blood pressure and anticoagulation.
Typical dosage: 100-200 mg daily
- gastrointestinal upset
- insomnia
- Consult healthcare provider before use with warfarin; may affect INR levels.
- Monitor for changes in blood pressure.
Take warfarin at the same time each day to maintain stable blood levels; avoid taking St. John's Wort.
- Do not use St. John's Wort while taking warfarin; consult healthcare provider for alternatives.
- Monitor INR levels closely if considering any new supplements.
Can you take St Johns Wort and Warfarin together?
St. John's Wort is known to interact with warfarin, potentially reducing its effectiveness and increasing the risk of thromboembolic events. Caution is advised when considering the use of St. John's Wort while on warfarin therapy.
How safe is the St Johns Wort and Warfarin combination?
Our analysis of publicly available medical sources scores this combination 3/10 (high risk). This is an informational estimate, not medical advice — always confirm with a healthcare professional.
When should you take St Johns Wort and Warfarin?
Take warfarin at the same time each day to maintain stable blood levels; avoid taking St. John's Wort.
What should you watch out for when combining St Johns Wort and Warfarin?
Do not use St. John's Wort while taking warfarin; consult healthcare provider for alternatives. Monitor INR levels closely if considering any new supplements.
Taking more than these two? Run your complete supplement list — plus any medications — through the live checker for a combined analysis.
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Analysis generated August 11, 2026 · Sources include NIH, Mayo Clinic, WebMD, and Examine.com · How our analysis works