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What Medicines Interact With Berberine? Medicine by Medicine
In this article
Berberine interacts with medicines in two ways. It slows three liver enzymes, CYP3A4, CYP2D6 and CYP2C9, that clear many common medicines, so the level of those medicines in the blood can rise; and it lowers blood glucose, so it adds to the effect of diabetes medicines. The best-documented interaction, in kidney-transplant patients, raised blood levels of ciclosporin by about 29%.1, 2 "What to do" never means stopping or changing a dose, which belong to the prescriber; the first step with every row is a conversation with your pharmacist, before you start or as soon as possible if you already have.
Sources checked on 30 October 2026.
- Strongest evidence: ciclosporin, trough levels about 29% higher; tacrolimus shares the enzyme
- Mechanism evidence: two weeks of berberine reduced CYP3A4, CYP2D6 and CYP2C9 activity in healthy men
- Additive effect: insulin, gliclazide and other glucose-lowering medicines
How does berberine interact with medicines?
Very little berberine reaches the blood, but concentrations in the gut wall and liver are high, and that is where it meets your medicines. In healthy men, 300 mg three times a day for two weeks increased the metabolic ratio of a CYP2D6 test drug nine-fold, doubled the ratio for a CYP2C9 test drug and raised exposure to a CYP3A4 test drug by 40%.2 It also inhibits transporters, including P-glycoprotein and the organic cation transporters that carry metformin.3, 4 The second mechanism is additive: berberine lowers glucose in trials, so it stacks with medicines that do the same; pooled placebo-controlled trials found no blood-pressure effect.4, 11 A 2026 review concluded that in people on several medicines berberine should be treated as an active pharmacological agent rather than an inert supplement.4 The enzyme effect was measured after two weeks of daily berberine, so a problem may appear weeks after starting; tell whoever monitors your medicine when you start and when you stop.2
Which medicines interact with berberine? Medicine by medicine
| Medicine (UK generic name) | What the evidence is | What to do and who to tell |
|---|---|---|
| Ciclosporin, tacrolimus (transplant and autoimmune medicines) | In 52 kidney-transplant patients, three months of berberine left ciclosporin trough levels about 29% higher than in 52 patients without it.1 | Do not start berberine without the transplant team's agreement; if you already take both, tell the team now so levels can be checked. |
| Metformin | Cell studies show berberine blocks the transporters that carry metformin; a human study of goldenseal, a berberine-containing plant, found no meaningful change in metformin exposure overall and a fall of about 20% at low metformin doses.3, 5 The practical concern is additive glucose lowering. | Tell the diabetes team or GP; keep monitoring as they advise; do not alter the metformin. |
| Gliclazide, glimepiride, insulin | These can cause low blood sugar on their own; berberine's glucose lowering adds to theirs. Pooled trials did not show more hypoglycaemia, but under trial supervision.6 | Tell the diabetes team before starting; know the hypo symptoms (shaking, sweating, hunger, confusion) and test if they appear.7 |
| Empagliflozin, dapagliflozin; semaglutide, tirzepatide, liraglutide | No interaction study. The concern is the same additive glucose lowering, and for the injectable medicines, additive gut symptoms. | Tell your prescriber or diabetes team before adding it. |
| Sertraline, citalopram, fluoxetine and other SSRIs; amitriptyline and other tricyclics | Berberine reduced CYP2D6 activity nine-fold by test-drug ratio; many antidepressants are cleared partly by CYP2D6, CYP2C19 or CYP3A4, so levels may rise.2 No clinical study. | Tell your GP or pharmacist before starting; report new side effects (agitation, sweating, tremor, palpitations) promptly; never stop an antidepressant on your own. |
| Warfarin | Cleared by CYP2C9, whose activity berberine roughly halved by test-drug ratio.2 No INR trial. | Tell the anticoagulant clinic before starting or stopping, and ask for an INR check within a week or two of either. |
| Apixaban, rivaroxaban, edoxaban, dabigatran | Cleared partly by CYP3A4 and P-glycoprotein, both reduced by berberine.2, 4 No clinical study. | Tell the GP or anticoagulant clinic; report unusual bruising or bleeding at once. |
| Clopidogrel, ticagrelor, aspirin (after a stent or stroke) | No interaction study with berberine. | Tell the cardiology team and follow their call. |
| Simvastatin, atorvastatin and other statins | A seven-day study in 60 healthy adults found no meaningful change in simvastatin or fenofibrate levels; reassuring but short and in healthy people, and the CYP3A4 effect still applies to simvastatin and atorvastatin.8 | Tell your pharmacist; report unexplained muscle pain or weakness. |
| Amlodipine, felodipine and other calcium-channel blockers; bisoprolol, propranolol, metoprolol and other beta-blockers | CYP3A4 and CYP2D6 substrates respectively; whether berberine lowers blood pressure is unproven.2, 4, 11 No clinical study. | Tell your GP or pharmacist; report dizziness, faintness or a slow pulse. |
| Levothyroxine | No pharmacokinetic study; in a 12-week pilot in obese adults, TSH and free T4 did not change.14 | Take levothyroxine on its own as the label says and berberine with meals hours later; tell the GP if thyroid tests change. |
| Iron (ferrous sulfate, ferrous fumarate) | No human study. | Leave a gap between the two and ask the pharmacist how long, as the NHS advises for iron with other supplements; tell the GP if ferritin is being tracked.9 |
| The combined pill and other hormonal contraception | No interaction study; two studies gave berberine to women already on a combined pill without measuring an interaction.12, 13 Berberine is unsuitable in pregnancy regardless. | Tell your pharmacist; use the contraception as prescribed and seek advice about any unexpected bleeding. |
What should you do if you already take berberine with one of these?
Do not stop the medicine, and do not change its dose. Tell the pharmacist or the team that monitors the medicine, say how much berberine you take and for how long, and let them decide whether a level, an INR, a glucose review or nothing at all is needed. The symptoms that should not wait are those of the medicine working too hard: a hypo, unusual bruising or bleeding, dizziness or a slow pulse, agitation or tremor.7 Berberine vs metformin and can you take berberine with or after Mounjaro cover those two combinations.
Before you take berberine with any medicine
Berberine displaces bilirubin from its carrier protein, which is why it is avoided in pregnancy, breastfeeding and infancy: in a jaundiced newborn the freed bilirubin can damage the brain.10 The French food-safety agency's 2019 opinion found significant therapeutic effects from 400 mg a day in treated adults and advised children, adolescents, pregnant and breastfeeding women, and people with diabetes or liver or heart conditions not to take berberine supplements.16 The rest of the safety picture is in berberine side effects; dose and timing are in how to take berberine; the berberine guide has the trials.
What we don't know
Human interaction studies exist for only a handful of pairings: ciclosporin, a set of enzyme test drugs, simvastatin and fenofibrate, and metformin with goldenseal; every other row in the table rests on mechanism rather than a clinical study.1, 2, 5, 8 No study has measured berberine with warfarin, a direct oral anticoagulant, an antidepressant or a GLP-1 medicine, and how quickly the enzyme effect fades after stopping has not been measured.2, 4 Berberine's safe intake is unsettled: EFSA's opinion on berberine plant preparations was still a draft out for consultation in 2026.15
Frequently asked questions
Can I take berberine with levothyroxine, and does it affect the TSH test?
No study has tested berberine with levothyroxine; in one 12-week pilot in obese adults, TSH and free T4 did not change, and the precaution in the table applies.14
Why did the hospital say to stop berberine after a stent?
Because the antiplatelet medicines that keep a new stent open must work predictably, and no interaction study says berberine leaves them alone.
Can I take berberine with metformin and empagliflozin?
Only after telling the diabetes team. All three lower glucose, so the risk is additive lowering; the goldenseal study suggests metformin exposure does not rise.5
Can I take berberine with iron if my ferritin is low?
Leave a gap between them, ask the pharmacist how long, and tell the GP tracking your ferritin. There is no human study; the precaution is the general NHS advice for iron with other supplements.9
Can I take berberine with sertraline?
Tell your GP or pharmacist first. Sertraline is cleared partly by CYP2D6 and CYP3A4, both reduced by two weeks of berberine, so its level could rise; there is no clinical study.2 Never stop sertraline on your own.
Sources
- Wu X, et al. European Journal of Clinical Pharmacology, 2005. Randomised trial, 104 kidney-transplant recipients, 3 months; funding not stated on PubMed. PubMed 16133554.
- Guo Y, et al. Repeated administration of berberine inhibits cytochromes P450 in humans. European Journal of Clinical Pharmacology, 2012. Randomised crossover, healthy men, 2 weeks; no conflicts declared. PubMed 21870106.
- Kwon M, et al. Organic cation transporter interaction between berberine and metformin. Archives of Pharmacal Research, 2015. Cell and rat study. PubMed 25359200.
- Dumitru CN, et al. Berberine-drug interactions. Pharmaceuticals, 2026. Narrative review; no conflicts declared. PubMed 42653808.
- Nguyen JT, et al. The pharmacokinetic interaction between metformin and goldenseal. Clinical and Translational Science, 2025. Three-arm crossover, adults with type 2 diabetes on metformin; no conflicts declared. PubMed 39943692.
- Xie W, et al. Glucose-lowering effect of berberine on type 2 diabetes. Frontiers in Pharmacology, 2022. Meta-analysis, 37 randomised trials, 3,048 adults with type 2 diabetes; no conflicts declared. PubMed 36467075.
- NHS. Low blood sugar (hypoglycaemia). nhs.uk/conditions/low-blood-sugar-hypoglycaemia. Read 30 October 2026; page last reviewed 3 August 2023 (review overdue).
- Li G, et al. Berberine chloride with simvastatin and fenofibrate. Drug Design, Development and Therapy, 2019. Randomised open-label study, 60 healthy adults, 7 days; no conflicts declared. PubMed 30587933.
- NHS. Taking ferrous sulfate with other medicines and herbal supplements. nhs.uk/medicines/ferrous-sulfate. Read 30 October 2026; page last reviewed 9 February 2023 (review overdue).
- Chan E. Displacement of bilirubin from albumin by berberine. Biology of the Neonate, 1993. Laboratory and rat study. PubMed 8513024.
- Liu D, et al. Efficacy and safety of berberine on the components of metabolic syndrome. Frontiers in Pharmacology, 2025. Meta-analysis of randomised placebo-controlled trials in metabolic syndrome; no conflicts declared. PubMed 40740996.
- Wei W, et al. European Journal of Endocrinology, 2012. Randomised trial, 89 women with PCOS on a cyproterone acetate pill, 3 months; funding not stated on PubMed. PubMed 22019891.
- Cicero AF, et al. High Blood Pressure and Cardiovascular Prevention, 2014. Uncontrolled study, 84 women on combined pills, berberine with monacolins, 3 months; funding not stated on PubMed. PubMed 24728953.
- Hu Y, et al. Phytomedicine, 2012. Uncontrolled pilot, obese adults, 500 mg three times a day for 12 weeks; funding not stated on PubMed. PubMed 22739410.
- EFSA NDA Panel. Draft scientific opinion on the safety of plant preparations containing berberine, endorsed 29 January 2026, public consultation 3 March to 11 May 2026. efsa.europa.eu. Read 30 October 2026.
- ANSES. Opinion on the safety of berberine-containing plants in food supplements, saisine 2018-SA-0095. Agency opinion, 1 August 2019. anses.fr.
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This article is general information, not medical advice. If you take any prescribed medicine, ask your pharmacist before starting berberine.
