Warfarin
Wondering whether you can take something with Warfarin (Coumadin)? Use this page to review interaction information.
2 supplements in this library have a recorded interaction with this medication
Dangerous combinations
Supplements recorded as risky with this medication2 listedHighest severity first
- →SupplementsChagaTheoreticalCaution
Chaga may theoretically increase bleeding risk with warfarin, but a specific CYP2C9 interaction and clinically documented elevation in INR have not been established.
- →SupplementsSea Moss (Irish Moss)TheoreticalCaution
Sea moss is not established to contain clinically significant amounts of vitamin K; any effect on warfarin is theoretical and product-dependent.
Where the evidence comes from
- Reference knowledge
Open Sea Moss (Irish Moss)Confidence
confidence 70/100
- Trade names
- Warfarin (Coumadin)
- family
- anticoagulants
Full write-up
What is it
Warfarin (Coumadin) is a medicine in the anticoagulant family, commonly described as a blood thinner. This page is an educational reference for reviewing how Warfarin may interact with other substances, including supplements and wellness products. It is not medical advice; questions about Warfarin, interactions, or any medical condition are best discussed with a clinician.
What interacts with it
Interactions with warfarin mainly fall into two opposing patterns: some supplements may weaken anticoagulation by lowering INR, while others may increase anticoagulant or antiplatelet effects and raise bleeding risk. Vitamin K-containing products are especially important because they directly oppose warfarin’s vitamin-K-antagonist effect. This includes Vitamin K1, Vitamin K2, and variable amounts of vitamin K in Chlorella. Coenzyme Q10, American Ginseng, St. John's Wort, and Vitamin C (>1g/day) may also reduce anticoagulant effect through different mechanisms. Changes in these products, including starting or stopping them, can therefore affect INR control.
A separate group may increase bleeding by adding antiplatelet activity or by increasing warfarin exposure. Examples include Garlic, Curcumin, Omega-3, Vitamin E, Black Seed Oil, and Glucosamine. CBD (Cannabidiol) and Milk Thistle (Silymarin) may increase warfarin exposure through effects on drug metabolism, while L-Carnitine, Acetyl-L-Carnitine (ALCAR), Melatonin, and Vitamin B3 (Niacin) may alter anticoagulation control through other reported effects. Dietary Fiber (Prebiotics) may affect warfarin response in some contexts, making consistent intake relevant.
Evidence is not equally strong for every combination. Chamomile is supported by an isolated case report, Holy Basil (Tulsi) has theoretical antiplatelet concerns without clinical studies or case reports demonstrating the interaction, and the effect of Panax Ginseng remains uncertain. Chondroitin Sulfate has been reported or theorized to affect bleeding risk. Because both reduced anticoagulation and excess anticoagulation can be clinically important, discuss supplement use and any changes with a prescriber or pharmacist; INR monitoring may be appropriate when certain products are started, stopped, or changed.