NutriStack
Glimepiride and Quercetin, a caution.
Quercetin inhibits CYP2C9 in human studies. Glimepiride is metabolized primarily by CYP2C9. Concentrated quercetin supplements can raise glimepiride exposure and prolong its hypoglycemic effect, especially in older adults or with missed meals.
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
- Glimepiride 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 inhibits CYP2C9 in human studies. Glimepiride is metabolized primarily by CYP2C9. Concentrated quercetin supplements can raise glimepiride exposure and prolong its hypoglycemic effect, especially in older adults or with missed meals.
Mechanism. Quercetin inhibits CYP2C9 at supplemental doses, raising plasma concentrations of CYP2C9 substrates including glimepiride. This prolongs and amplifies the hypoglycemic effect.
Recommendation. Avoid concentrated quercetin supplements (>500 mg/day) on glimepiride unless your prescriber agrees. Dietary quercetin from foods is generally fine. If you take a supplement, monitor glucose more often during the first 2-4 weeks and discuss whether glimepiride should be reduced.
Sources (2)
- Bedada SK, Neerati P. Evaluation of the effect of quercetin treatment on CYP2C9 enzyme activity of diclofenac in healthy human volunteers. Phytother Res. 2018;32(2):305-311. PMID 29168292
- Si D, Wang Y, Zhou YH, et al. Mechanism of CYP2C9 inhibition by flavones and flavonols. Drug Metab Dispos. 2009;37(3):629-634. PMID 19074529
Stack Score
How this pair moves the number.
Effect on the composite score
If both Glimepiride 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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