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 we hold evidence for is with diabetes medication: silymarin may lower blood sugar, so alongside metformin, gliclazide, glimepiride or insulin the effects can add up and glucose is worth monitoring. A mild effect on medicines cleared by the CYP2C9 or CYP3A4 enzymes is possible but we hold no specific pairing for it, so mention silymarin if you take several drugs rather than treating that as a known clash. 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 lists the evidence its assessment drew on: some rest on studies of the exact pair, others on mechanism evidence, where a citation may support one part of the reasoning rather than the exact combination. The evidence line on each entry says which.
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, from small studies or case reports, alongside 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, from small studies or case reports, alongside 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, from small studies or case reports, alongside 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, from small studies or case reports, alongside 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.
Read the full methodologyA full supplement review, built around you, not a generic stack.
The free checker answers one interaction question at a time. A Distil report reviews the bigger picture: your goals, diet, medications, current supplements and any blood results you provide, then shows what appears worth keeping, changing, adding or leaving out.
- what your diet already covers, so you are not adding a capsule for something food is already handling
- which evidence-graded compounds are worth considering for your goals, and which were considered but left out
- what to keep, change or stop from what you already take, plus the order to introduce anything new
- how your medications and complete supplement stack fit together, with daily timing and a clear point for reassessment
The interaction check is one section of the full report. You also get the reasoning behind each recommendation and the evidence references used.
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