NutriStack
Glimepiride and Milk Thistle, a caution.
Glimepiride is metabolized primarily by CYP2C9. Silymarin (milk thistle) inhibits CYP2C9 in vitro and has independent hypoglycemic activity. The combination can raise glimepiride exposure and amplify its glucose-lowering, producing hypoglycemia particularly 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 Milk Thistle
- 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. Glimepiride is metabolized primarily by CYP2C9. Silymarin (milk thistle) inhibits CYP2C9 in vitro and has independent hypoglycemic activity. The combination can raise glimepiride exposure and amplify its glucose-lowering, producing hypoglycemia particularly in older adults or with missed meals.
Mechanism. Silymarin modestly inhibits CYP2C9, the main enzyme metabolizing glimepiride, potentially raising plasma concentrations. Silymarin also improves insulin sensitivity independently. Combined pharmacokinetic and pharmacodynamic effects amplify hypoglycemia risk.
Recommendation. Tell your prescriber before adding milk thistle on glimepiride. Monitor fingerstick glucose more often during the first 4 weeks and ask whether the glimepiride dose should be reduced.
Sources (2)
- Kawaguchi-Suzuki M, Frye RF, Zhu HJ, et al. The effects of milk thistle (Silybum marianum) on human cytochrome P450 activity. Drug Metab Dispos. 2014;42(10):1611-1616. PMID 25028567
- Voroneanu L, Nistor I, Dumea R, Apetrii M, Covic A. Silymarin in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Diabetes Res. 2016;2016:5147468. PMID 27340676
Stack Score
How this pair moves the number.
Effect on the composite score
If both Glimepiride and Milk Thistle 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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