Silymarin and medications.
Silymarin is in the Distil supplement database, evidence Grade A/B. The page below lists every medication we have explicitly assessed it against.
Silymarin, the active fraction of milk thistle, is one of the better-studied liver compounds, rated Grade A/B for liver health. It works as an antioxidant and membrane stabiliser in liver cells, and the evidence supports lower liver enzymes (ALT and AST) in fatty liver disease and a mortality benefit in cirrhosis across pooled trials. The honest limit is that benefit is clearest in established liver conditions; it is not a general detox supplement. Typical dosing is 420 to 600mg daily of standardised extract, split into two or three doses. It pairs well with NAC and phosphatidylcholine, which share complementary liver-support mechanisms. The interaction to watch is with medications cleared by the CYP2C9 or CYP3A4 enzymes, where a mild interaction is possible, so flag it if you take several drugs. It is among the safest herbal compounds, though those in the ragweed family should check for allergy. Its safety in pregnancy is not established by the trials behind this assessment, so treat that as a question for a clinician rather than an assumption. If a liver condition is the target, this is a primary candidate.
Below are the 4 documented pairs we have explicitly assessed for Silymarin: 4 amber. The pairs cluster around 1 mechanism: Additive glucose lowering. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not listed here is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by medication, and the missing-item form at the bottom of the page routes any uncatalogued medication into our next curation pass.
Documented interactions
Last reviewed 14 June 2026. Each interaction below is assessed against PubMed-indexed evidence.
Additive glucose lowering
Amber Does interact with Gliclazide?
Milk thistle (silymarin) may lower blood sugar, and gliclazide already lowers it, so taking the two together may add up and could push your glucose too low. Gliclazide is one of the diabetes tablets most likely to cause low blood sugar on its own. If you take both, monitor your blood glucose, especially in the first few weeks, and your doctor may need to adjust the gliclazide dose.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Glimepiride?
Milk thistle (silymarin) may lower blood sugar, and glimepiride already lowers it, so taking the two together may add up and could push your glucose too low. Glimepiride is a sulfonylurea, the type of diabetes tablet most likely to cause low blood sugar. If you take both, monitor your blood glucose, especially early on, and your doctor may need to adjust the glimepiride dose.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Insulin glargine?
Milk thistle (silymarin) may lower blood sugar by improving how your body responds to insulin, which can add to the insulin you inject and increase the chance of glucose going too low. If you take silymarin with insulin, monitor your blood glucose closely, especially early on, and your doctor may need to reduce your insulin dose.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Metformin?
Milk thistle (silymarin) may lower blood sugar, and metformin also lowers it, so the two may add up. The combination is generally manageable because metformin rarely causes low blood sugar on its own, but monitor your blood glucose when you start silymarin or change the dose, and your doctor may adjust the metformin if needed.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope. Use the checker below to surface any medication, and submit a missing item if you take something we have not catalogued.
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How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
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