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 Saw Palmetto + Warfarin pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Interaction databaseSupplement × PrescriptionReviewed May 2026

Saw Palmetto and Warfarin, a caution.

Q: Can I take Saw Palmetto and Warfarin together?

Possibly, but with caution. Saw Palmetto and Warfarin have a documented caution-tier interaction. Saw palmetto has been linked to coagulopathy and excessive surgical bleeding in case reports, including hematuria and intraoperative hemorrhage. Pharmacokinetic data suggest mild CYP2C9 inhibition, which could slow warfarin metabolism. The signal is modest but clinically relevant given warfarin's narrow therapeutic window.

Q: How does this affect a NutriStack Stack Score?

-5 to your Stack Score per scored caution row.

Saw palmetto has been linked to coagulopathy and excessive surgical bleeding in case reports, including hematuria and intraoperative hemorrhage. Pharmacokinetic data suggest mild CYP2C9 inhibition, which could slow warfarin metabolism. The signal is modest but clinically relevant given warfarin's narrow therapeutic window.

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: Saw Palmetto 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. Saw palmetto has been linked to coagulopathy and excessive surgical bleeding in case reports, including hematuria and intraoperative hemorrhage. Pharmacokinetic data suggest mild CYP2C9 inhibition, which could slow warfarin metabolism. The signal is modest but clinically relevant given warfarin's narrow therapeutic window.

Mechanism. Saw palmetto extracts have been shown in vitro to inhibit COX and 5-lipoxygenase pathways and mildly inhibit CYP2C9. Antiplatelet activity from these pathways may add to warfarin's anticoagulation; CYP2C9 inhibition could raise warfarin levels.

Recommendation. Avoid saw palmetto while taking warfarin unless your prescriber has approved it. If you take it for prostate symptoms, tell your anticoagulation clinic, keep the dose constant, and ask for an INR check within 1-2 weeks.

Sources (2)

Stack Score

How this pair moves the number.

Effect on the composite score

If both Saw Palmetto 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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