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Supplement · Grade B

Glucosamine and medications.

Every documented pair, every citation. Below: 2 documented pairs grouped by mechanism.

Glucosamine is in the Distil supplement database, evidence Grade B. The page below lists every medication we have explicitly assessed it against.

Glucosamine is an amino sugar found in cartilage, usually paired with chondroitin sulfate and taken for the joint pain of moderate osteoarthritis. The standard dose is glucosamine sulfate 1,500mg with chondroitin sulfate 1,200mg, and the form matters: the sulfate salt is the one with trial evidence, not the HCl version. The evidence is Grade B for pain relief in moderate-to-severe OA, weaker in mild OA, and Grade C for any actual preservation of cartilage. The large GAIT trial showed mixed results overall, which is why this sits in the honest middle rather than the headline tier. On interactions, the main thing to know is the shellfish angle: most glucosamine is shellfish-derived, so anyone with that allergy should use the corn-fermentation form instead. It tends to cause mild stomach upset, so take it with food. A practical note: give it a steady eight to twelve weeks before judging whether it helps your joints.

Below are the 2 documented pairs we have explicitly assessed for Glucosamine: 2 amber. The pairs cluster around 1 mechanism: Additive anticoagulation. 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

Additive anticoagulation

Glucosamine (often with chondroitin) has been reported to increase the blood-thinning effect of acenocoumarol and raise the INR, sometimes enough to cause bleeding. If you take acenocoumarol, it is best to avoid glucosamine or only use it with your anticoagulant clinic's knowledge and extra INR checks.

PMID 18363538 · BNF: Acenocoumarol

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Glucosamine can push warfarin's blood-thinning effect higher, raising your INR and your bleeding risk. This shows up more when the glucosamine dose goes up. If you take warfarin, tell your anticoagulation clinic before starting glucosamine and ask for an INR check within a couple of weeks, especially if you change the dose.

PMID 18363538 · BNF: Warfarin

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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For adults over 18. This tool gives evidence-graded information, not medical advice. Always discuss changes with your GP, especially if you take any medication, are pregnant, breastfeeding, or have a serious health condition.
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How we grade severity, choose what's in scope, and what we exclude.

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Distil's interactions database is reviewed and updated every quarter. We grade evidence transparently and publish our methodology, including every database change, at /about/methodology. This tool is information, not a substitute for clinical judgement. If you take medication and supplements together, your GP or pharmacist can review your full regimen against your medical history. If you want a full personalised stack reasoned against this same database, the Distil report is the next step up.