NutriStack
Chondroitin and Warfarin, a caution.
Chondroitin is structurally a heparan-like sulfated glycosaminoglycan and is commonly taken with glucosamine for joint pain. Combined glucosamine-chondroitin use has been linked to INR elevation in warfarin patients across multiple case reports and pharmacovigilance databases, with at least one fatal intracerebral bleed reported.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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What the row says.
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At a glance
- Substances
- Chondroitin and Warfarin
- Pair type
- Caution
- Evidence (highest tier)
- Moderate
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Moderate evidence
Caution
What is happening. Chondroitin is structurally a heparan-like sulfated glycosaminoglycan and is commonly taken with glucosamine for joint pain. Combined glucosamine-chondroitin use has been linked to INR elevation in warfarin patients across multiple case reports and pharmacovigilance databases, with at least one fatal intracerebral bleed reported.
Mechanism. Chondroitin sulfate is structurally similar to heparan sulfate and may have intrinsic mild anticoagulant activity. Combined with glucosamine, it has been linked clinically to INR elevation in warfarin users, although the precise pharmacological mechanism is not fully defined.
Recommendation. Avoid chondroitin (including glucosamine-chondroitin combinations) while on warfarin. If you need joint support, tell your anticoagulation clinic before starting any new supplement and ask for an INR check within 1-2 weeks.
Sources (2)
- Knudsen JF, Sokol GH. Potential glucosamine-warfarin interaction resulting in increased international normalized ratio: case report and review of the literature and MedWatch database. Pharmacotherapy. 2008;28(4):540-8. PMID 18363538
- Tan CSS, Lee SWH. Warfarin and food, herbal or dietary supplement interactions: A systematic review. Br J Clin Pharmacol. 2021;87(2):352-374. PMID 32478963
Stack Score
How this pair moves the number.
Effect on the composite score
If both Chondroitin and Warfarin are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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