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What Medicines Interact With Berberine? Medicine by Medicine
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 a third.1, 2 The table below goes medicine by medicine in UK generic names. "What to do" is never "stop" or "change the dose": those decisions belong to the prescriber, and the first step with every row is a conversation with your pharmacist, before you start or as soon as possible if you already have.
- Strongest evidence: ciclosporin and tacrolimus, blood levels about a third higher
- 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 Those enzymes clear many prescribed medicines: many antidepressants and beta-blockers (CYP2D6), warfarin (CYP2C9), and statins, calcium-channel blockers, ciclosporin, tacrolimus and the newer anticoagulants (CYP3A4). 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 and modestly lowers blood pressure in trials, so it stacks with medicines that do the same.4 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 built up over two weeks, so a problem may appear weeks after starting, and it reverses when you stop, so starting and stopping both deserve a mention to whoever monitors your medicine.
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; the best-documented human interaction.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, since both lower glucose. | 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; do not add berberine to a new or changing regimen without asking. |
| 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; the French food-safety agency lists warfarin among berberine's interactions.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; one unverified case report of raised rivaroxaban levels.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. Clopidogrel is activated by liver enzymes, and after a stent an unpredictable antiplatelet level matters most. | Hospitals ask people to stop supplements after a stent for exactly this reason; 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; berberine also lowered blood pressure modestly in trials, so dizziness has two possible routes.2, 4 No clinical study. | Tell your GP or pharmacist; report dizziness, faintness or a slow pulse. |
| Levothyroxine | No pharmacokinetic study and no evidence that berberine affects thyroid hormone or TSH tests. Like iron and calcium, it is a plausible absorption competitor if swallowed together. | 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; plant alkaloids can bind iron in the gut, and readers with low ferritin report slower rises. | Separate by at least two hours, as the NHS advises for other supplements with iron; tell the GP if ferritin is being tracked.9 |
| The combined pill and other hormonal contraception | No data either way. Oestrogen is cleared by CYP3A4, so a rise rather than a fall would be the theoretical direction; 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 Nothing on this page is a reason to go without a prescribed medicine; berberine vs metformin explains why swapping is not the choice it looks like, and if the medicine is Mounjaro, can you take berberine with or after Mounjaro covers that combination.
Who should not take berberine at all?
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 It is not for children or for women trying to conceive. The French food-safety agency judged berberine to have drug-like effects from 400 mg a day in adults and advised children, adolescents, pregnant and breastfeeding women, and people with diabetes or liver or heart conditions not to take berberine supplements without medical advice. European food-safety regulators have been reviewing berberine's safety data during 2026. The rest of the safety picture, gut symptoms, lows, liver and mood reports, is in berberine side effects; dose, timing and forms are in how to take berberine; and the Wellgard berberine guide sets out the trial evidence.
Frequently asked questions
Can I take berberine with levothyroxine, and does it affect the TSH test?
No study has looked at either. Nothing suggests berberine changes thyroid hormone levels or the TSH assay; the sensible precaution is to keep levothyroxine on its own, as the label says, and take berberine with meals later in the day. Tell your GP you take it if your thyroid tests move.
Why did the hospital say to stop berberine after a stent?
Because the antiplatelet medicines that keep a new stent open, clopidogrel or ticagrelor with aspirin, must work predictably, and berberine's effect on liver enzymes and transporters makes a supplement an unknown in that equation. There is no interaction study to say it is safe, so the cardiology team removes the unknown.
Can I take berberine with metformin and empagliflozin?
Only after telling the diabetes team. All three lower glucose, so the risk is additive lowering rather than a chemical clash; the goldenseal study suggests metformin exposure does not rise.5 Apple cider vinegar and cinnamon add no documented interaction; the same rule applies.
Can I take berberine with iron if my ferritin is low?
Separate them by at least two hours and tell the GP tracking your ferritin. There is no human study; the precaution rests on how plant alkaloids behave in the gut.9
Does berberine interact with glucomannan or other fibre supplements?
No data. Soluble fibre can slow the absorption of medicines taken at the same time, so take prescribed medicines apart from fibre as their labels say.
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. Effects of berberine on the blood concentration of cyclosporin A in renal transplanted recipients: clinical and pharmacokinetic study. European Journal of Clinical Pharmacology, 2005. PubMed 16133554.
- Guo Y, et al. Repeated administration of berberine inhibits cytochromes P450 in humans. European Journal of Clinical Pharmacology, 2012. PubMed 21870106.
- Kwon M, et al. Organic cation transporter-mediated drug-drug interaction potential between berberine and metformin. Archives of Pharmacal Research, 2015. PubMed 25359200.
- Dumitru CN, et al. Berberine-drug interactions: mechanisms, clinical relevance and risk stratification, a narrative review. Pharmaceuticals, 2026. PubMed 42653808.
- Nguyen JT, et al. The pharmacokinetic interaction between metformin and the natural product goldenseal is metformin dose-dependent. Clinical and Translational Science, 2025. PubMed 39943692.
- Xie W, et al. Glucose-lowering effect of berberine on type 2 diabetes: a systematic review and meta-analysis. Frontiers in Pharmacology, 2022. PubMed 36467075.
- NHS. Low blood sugar (hypoglycaemia). nhs.uk/conditions/low-blood-sugar-hypoglycaemia.
- Li G, et al. Pharmacokinetic interactions and tolerability of berberine chloride with simvastatin and fenofibrate: an open-label, randomized, parallel study in healthy Chinese subjects. Drug Design, Development and Therapy, 2019. PubMed 30587933.
- NHS. Taking ferrous sulfate with other medicines and herbal supplements. nhs.uk/medicines/ferrous-sulfate.
- Chan E. Displacement of bilirubin from albumin by berberine. Biology of the Neonate, 1993. PubMed 8513024.
This article is general information, not medical advice. If you take any prescribed medicine, ask your pharmacist before starting berberine, and never stop or change a medicine on your own.
