Ranked by how strong the human evidence is — best supported first.
Best supportedGut microbiomeNot enough evidence· no source yetThen, in order
The long taproot of a biennial thistle, eaten as a vegetable in Japan as gobo and sold as a dried root or extract. It contains inulin, lignans and polyphenols.
Burdock is a common ingredient in "blood purifying" and cleanse formulas, a framing with no physiological meaning. Human research is close to absent — a small Iranian trial in knee osteoarthritis and a few metabolic pilot studies. The most important practical hazard is misidentification: burdock root resembles belladonna root, and burdock tea contaminated with belladonna has caused anticholinergic poisoning.
The amounts, forms and durations published trials of Burdock root actually administered.
These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.
Studied for General supplement use
500–2000 mg
Dried root or extract capsule
Trial dosing is not established. The few human studies used root tea or extracts at amounts that were not consistent between studies and were never dose-ranged.
This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.
Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.
None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.
No timing has been studied for burdock in humans.
Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.
What each association actually rests on, and the papers behind it. A rating describes the state of the research, not how promising the supplement sounds. How we rate evidence.
There is not enough human research on burdock and the gut microbiome. Its inulin content is a plausible prebiotic source, but that has been studied for inulin rather than for burdock.
Not enough evidence. Not enough human research to say anything useful yet.
Evidence is limited for burdock and inflammation. One small trial reported reduced inflammatory markers in knee osteoarthritis; it has not been replicated.
Not enough evidence. Not enough human research to say anything useful yet.
Randomised controlled trial · JBRA assisted reproduction · 2026 · PMID 41757842
Randomised controlled trial · Helicobacter · 2018 · PMID 29520881
Randomised controlled trial · Journal of cosmetic dermatology · 2008 · PMID 19146605
Randomised controlled trial · International journal of rheumatic diseases · 2016 · PMID 25350500
Deep research mode adds each paper’s own conclusion and stated limitations.
Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.
Worth knowing
Burdock root resembles the root of deadly nightshade, and burdock tea contaminated with belladonna has caused atropine poisoning — dry mouth, blurred vision, hallucinations and rapid heart rate. Wild harvesting is genuinely dangerous.
Allergy
Burdock is a daisy-family plant and can cause reactions in people sensitised to ragweed, chrysanthemum or related species, including contact dermatitis.
Interaction
Interacts withInsulin, sulfonylureas, diuretics
Burdock has been reported to lower blood glucose and to have a mild diuretic effect, both of which may add to medication.
Avoid
Burdock has traditional uterine-stimulant use and is generally avoided in pregnancy in supplemental amounts.
Worth knowing
Burdock appears in products described as blood purifiers or cleanses. Neither describes a real physiological process, and no human trial supports either use.
The whole-food form, where one exists. The evidence for a concentrated extract rarely transfers to the food, or the other way round — these are cross-links, not equivalents.