Supplements and Clopidogrel.
Clopidogrel, sold under the brand name Plavix, is an antiplatelet agent: it reduces platelet aggregation.
Clopidogrel is the second line antiplatelet agent in UK secondary cardiovascular prevention. It is often co-prescribed with aspirin after stent placement (dual antiplatelet therapy) or used alone where aspirin is not tolerated. Clopidogrel is a prodrug requiring CYP2C19 activation, and this is where the supplement story differs from aspirin. Inhibition of CYP2C19 can reduce clopidogrel's antiplatelet effect, leaving the patient effectively on weaker antiplatelet cover. The clearest case is omeprazole; some supplements at high concentrations show the same effect in vitro but rarely clinically. The BNF and MHRA both flag this. Additive antiplatelet interactions seen with aspirin (ginkgo, garlic extract, fish oil at higher doses, curcumin, bromelain, andrographis, nattokinase) apply to clopidogrel too. The washout window before surgery is the same. The CYP2C19 poor metaboliser genotype affects roughly 3 to 5 percent of UK patients of European ancestry and a higher proportion of East Asian ancestry. It explains some unexplained stent thromboses.
Below are the 11 documented pairs we have explicitly assessed against Clopidogrel in the Distil database: 11 amber. The pairs cluster around 1 mechanism: Additive antiplatelet effect. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not on this list is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by supplement, and the missing-item form at the bottom of the page routes any uncatalogued supplement 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 antiplatelet effect
Amber Does Andrographis interact with ?
Andrographis has a mild blood-thinning signal in laboratory studies, so in theory it could add to clopidogrel's effect on platelets and slightly raise bleeding risk. A small one-day study in healthy people found no clear change, so any real effect looks modest. If you take clopidogrel, tell your doctor or pharmacist before starting andrographis, and watch for easy bruising or unusual bleeding.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Bromelain interact with ?
Bromelain has mild blood-thinning activity that can add to clopidogrel's. Tell your GP if you take bromelain alongside clopidogrel long-term, and stop high-dose bromelain about two weeks before any planned surgery.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Curcumin interact with ?
Curcumin has a mild blood-thinning effect of its own, so taking it with clopidogrel may add to the bleeding risk. The combination is worth stopping before any planned surgery or dental work, and worth mentioning to your GP.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Fisetin interact with ?
Fisetin may mildly reduce platelet clumping, which could add a little to clopidogrel's blood-thinning effect. This is most relevant during a high-dose fisetin course. If you take clopidogrel and run a fisetin course, mention it to your GP and watch for unusual bruising or bleeding.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Garlic Extract interact with ?
Garlic has mild blood-thinning activity that can add to clopidogrel's. Stop high-dose garlic supplements at least a week before any surgery and tell your GP if you take garlic alongside clopidogrel long-term.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does Ginger interact with ?
Both ginger and clopidogrel can reduce platelet stickiness, so in theory high-dose ginger supplements could add slightly to clopidogrel's blood-thinning effect. This is based on how ginger behaves in the laboratory rather than on studies of people taking both together, so any real-world effect is likely small. Dietary ginger is not a concern. If you take high-dose ginger supplements with clopidogrel, stop them about a week before any planned surgery or dental procedure and let the team know.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Ginkgo Biloba interact with ?
Both ginkgo and clopidogrel reduce platelet aggregation, so combining them increases bleeding risk additively. The combination is worth stopping six weeks before any planned surgery or dental procedure.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does Omega-3 EPA interact with ?
Standard supplement doses of fish oil (under 1 gram of EPA+DHA per day) add only marginally to the antiplatelet effect of clopidogrel. At higher cardiology doses (3 grams per day and above), the combination meaningfully increases bleeding risk.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does Pine Bark Extract interact with ?
Pine bark extract (pycnogenol) has a mild blood-thinning effect of its own, most clearly shown in smokers, that can add to clopidogrel's. For most people the combined effect is no more than a small extra tendency to bruise or bleed. Stop high-dose pine bark extract at least a week before any planned surgery and tell your GP if you take the two together long-term or notice easy bruising.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Resveratrol interact with ?
Resveratrol can mildly reduce platelet clumping, which adds to clopidogrel's blood-thinning effect and may slightly raise bleeding risk. Concentrated supplements are the concern, not food amounts. If you take clopidogrel and use resveratrol, mention it to your GP and watch for unusual bruising or bleeding.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Vitamin E interact with ?
At low supplement doses (100 to 200 IU) vitamin E adds little to clopidogrel. At high doses (above 400 IU per day) it can add to clopidogrel's blood-thinning effect and raise bleeding risk. Keep vitamin E to modest mixed-tocopherol doses and stop high-dose vitamin E six weeks before any surgery.
Evidence: Limited human data, based on case reports and a known mechanism.
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 (food-supplement interactions only; for drug-drug interactions, the BNF is authoritative). Use the checker below to surface any supplement, 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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