What kind of interaction is it?

Caution: an interaction that may reduce efficacy or raise side-effect risk and warrants monitoring.

Is this interaction backed by published research?

Yes. NutriStack lists 2 citation rows for the Pine Bark Extract + Warfarin pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Interaction databaseSupplement × PrescriptionReviewed May 2026

Pine Bark Extract and Warfarin, a caution.

Q: Can I take Pine Bark Extract and Warfarin together?

Possibly, but with caution. Pine Bark Extract and Warfarin have a documented caution-tier interaction. Pine bark extract (pycnogenol) inhibits platelet aggregation and reduces thromboxane generation. Combined with warfarin, these pharmacodynamic antiplatelet effects can additively raise bleeding risk even without changing the INR.

Q: How does this affect a NutriStack Stack Score?

-5 to your Stack Score per scored caution row.

Pine bark extract (pycnogenol) inhibits platelet aggregation and reduces thromboxane generation. Combined with warfarin, these pharmacodynamic antiplatelet effects can additively raise bleeding risk even without changing the INR.

2 primary source citations. Emerging evidence. Last verified May 30, 2026.

Open the interaction checker →Read the methodology

One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.

Sourcing standards·Evidence tiers

From the interaction database

What the row says.

Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.

At a glance

Substances: Pine Bark Extract and Warfarin
Pair type: Caution
Evidence (highest tier): Emerging
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 · Emerging evidence

Caution

What is happening. Pine bark extract (pycnogenol) inhibits platelet aggregation and reduces thromboxane generation. Combined with warfarin, these pharmacodynamic antiplatelet effects can additively raise bleeding risk even without changing the INR.

Mechanism. Procyanidins in pine bark extract inhibit platelet aggregation by reducing thromboxane A2 generation and modulating platelet receptor signaling. This is a pharmacodynamic effect that adds to warfarin's reduction of clotting factor synthesis without altering the INR.

Recommendation. Avoid pine bark extract supplements on warfarin. If you take it, keep the dose constant, watch for unusual bruising or bleeding, and tell your anticoagulation clinic before any dose change.

Sources (2)

Stack Score

How this pair moves the number.

Effect on the composite score

If both Pine Bark Extract 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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