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

Interaction databaseSupplement × PrescriptionReviewed May 2026

Glipizide and Quercetin, a caution.

Q: Can I take Glipizide and Quercetin together?

Possibly, but with caution. Glipizide and Quercetin have a documented caution-tier interaction. Quercetin is a flavonoid that inhibits CYP2C9 in human studies (it reduced diclofenac CYP2C9-mediated metabolism at 500 mg twice daily). Glipizide is metabolized primarily by CYP2C9. The combination can raise glipizide exposure and amplify its glucose-lowering, particularly at concentrated supplemental doses (versus dietary quercetin from fruits and vegetables).

Q: How does this affect a NutriStack Stack Score?

-5 to your Stack Score per scored caution row.

Quercetin is a flavonoid that inhibits CYP2C9 in human studies (it reduced diclofenac CYP2C9-mediated metabolism at 500 mg twice daily). Glipizide is metabolized primarily by CYP2C9. The combination can raise glipizide exposure and amplify its glucose-lowering, particularly at concentrated supplemental doses (versus dietary quercetin from fruits and vegetables).

2 primary source citations. Moderate 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: Glipizide and Quercetin
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. Quercetin is a flavonoid that inhibits CYP2C9 in human studies (it reduced diclofenac CYP2C9-mediated metabolism at 500 mg twice daily). Glipizide is metabolized primarily by CYP2C9. The combination can raise glipizide exposure and amplify its glucose-lowering, particularly at concentrated supplemental doses (versus dietary quercetin from fruits and vegetables).

Mechanism. Quercetin and other flavonols inhibit CYP2C9 (Ki ~1-2 microM) by binding the active site. CYP2C9 is the primary enzyme metabolizing glipizide, so inhibition raises plasma drug concentrations and prolongs the hypoglycemic effect.

Recommendation. Avoid concentrated quercetin supplements (>500 mg/day) on glipizide unless your prescriber agrees. If you take both, monitor fingerstick glucose more often during the first 2-4 weeks and ask whether the glipizide dose should be reduced. Dietary quercetin from foods is unlikely to matter clinically.

Sources (2)

Stack Score

How this pair moves the number.

Effect on the composite score

If both Glipizide and Quercetin 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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