Berberine Side Effects and Medicine Interactions: Liver Enzymes, Diabetes Drugs and More
Common berberine side effects and what is known about medicine interactions, from liver enzymes and cyclosporine to diabetes drugs, with a plain note on what is proven and what is predicted.
Content last updated . This page has not been medically reviewed.
Before anything else
Berberine can change how some medicines are absorbed and cleared, and it can add to the effect of some medicines. Tell your pharmacist or prescriber about any berberine or goldenseal product you take, including before surgery. Do not stop or change a prescribed medicine on your own. Call 911 for severe symptoms such as fainting, chest pain or trouble breathing. For a child who swallowed a supplement, call Poison Help at 1-800-222-1222 (US); other countries are on Poison Help by country.Common side effects
Stomach and bowel symptoms such as constipation and diarrhea are the most commonly reported. [1] In 18 placebo-controlled trials lasting 4 to 24 weeks, gastrointestinal side effects tended to be more frequent with berberine, and no serious adverse events were reported. [2] Short trials cannot rule out rarer or longer-term harm.A toxicology review says toxicity depends on route and duration, and that berberine and barberry could cause stomach upset and ulceration, immune, nerve, heart and skin-sensitivity effects and jaundice in a dose-dependent manner. [3] The abstract does not say how often these occur in people. Another 2026 review reports toxicity affecting the liver, kidney, heart and immune system under specific doses and conditions, and lists pregnancy status and liver and kidney function among the factors. [4]
How interactions work, and what is proven
A 2026 review explains that very little berberine reaches the bloodstream, but high concentrations in the gut and liver can still create interaction risk. [5] The interactions are documented in people for only a few medicine pairs and are mechanistic (predicted from lab work) for most. [5]| Medicine or group | What the sources say | How firm |
|---|---|---|
| Cyclosporine (transplant) | The review's clinical anchor is higher cyclosporine exposure in kidney-transplant recipients (AUC +34.5%). [5] | Shown in people |
| Medicines cleared by CYP3A4, CYP2D6, CYP2C9 enzymes | Lab work shows berberine inhibits CYP2D6 and CYP3A4/5 in human liver preparations. [6] A review of human studies found weak CYP3A4 and CYP2D6 inhibition for goldenseal/berberine at common doses. [7] | Lab plus weak human data |
| Goldenseal products and CYP enzymes | In 12 healthy volunteers, goldenseal strongly inhibited CYP2D6 and CYP3A4/5. [8] Goldenseal is a mixed plant, not pure berberine, so this is not proof for berberine alone. | Shown in a small study |
| Diabetes medicines | Reviews list added blood-sugar lowering (hypoglycemia) as a possible additive effect. [5] | Predicted |
| Blood pressure and heart-rhythm medicines | Additive low blood pressure and QT prolongation are listed as possible. [5] | Predicted |
| Metformin | Reviews name metformin among drugs where interaction may occur. [9] In adults with type 2 diabetes, a goldenseal study found no clinically meaningful change in metformin levels overall, though the authors advised caution. [10] | Mixed |
| Kinase-inhibitor cancer drugs | A computer model predicted higher exposure to one such drug with a high berberine amount; the authors said controlled studies were needed. [11] | Modeled only |
Medicines with a narrow safety margin (small gap between a working and a harmful level) deserve the most care. [5] The review recommends that berberine use be asked about routinely when medicines are reviewed. [5] Bring the product label to the appointment.
Liver, kidney and other conditions
The toxicology reviews list liver and kidney function among factors that change risk. [4] One meta-analysis in fatty liver disease reported mild gastrointestinal side effects only. [12] Another found no significant effect on ALT and AST (liver enzymes) overall. [13] That is reassuring only for those studied groups. See liver safety and supplements and berberine in pregnancy, infants and liver conditions.Product quality
The interaction review treats product quality as a separate problem: contents vary and national limits in Europe differ by more than tenfold. [5] See quality testing and certifications. General background: medication interactions and interactions by drug class. Overview: berberine.Frequently asked questions
Does berberine interact with medicines?
Yes, in some cases. Cyclosporine is the best documented; most others are predicted from lab studies. [5]
Can berberine cause low blood sugar?
The larger glucose meta-analysis did not find significantly more hypoglycemia, but additive effects with diabetes drugs are listed as possible. [14] [5]
Can I take berberine with metformin?
Ask your prescriber or pharmacist. Reviews list metformin as a possible interaction, and one goldenseal study suggested caution. [9] [10]
Should I tell my doctor before surgery?
Yes, tell your surgical and anesthesia team about all supplements. We did not find a berberine-specific surgery statement in the sources we read.
Is berberine hard on the liver?
Evidence is mixed and limited: trials in fatty liver disease reported mild side effects, while toxicology reviews describe liver toxicity under certain doses and conditions. [12] [4] Ask a clinician if you have liver disease.
References
- Berberine and health outcomes: An umbrella review. Phytotherapy research : PTR, 2023. Read 2026-10-23.
- Overall and Sex-Specific Effect of Berberine for the Treatment of Dyslipidemia in Adults: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials. Drugs, 2023. Read 2026-10-23.
- Toxicology effects of Berberis vulgaris (barberry) and its active constituent, berberine: a review. Iranian journal of basic medical sciences, 2017. Read 2026-10-23.
- Balancing efficacy and risk: A toxicological review and safety transformation of Berberis plants and their alkaloids. Phytomedicine : international journal of phytotherapy and phytopharmacology, 2026. Read 2026-10-23.
- Berberine-Drug Interactions: Mechanisms, Clinical Relevance and Risk Stratification-A Narrative Review. Pharmaceuticals (Basel, Switzerland), 2026. Read 2026-10-23.
- Modulation of Major Human Liver Microsomal Cytochromes P450 by Component Alkaloids of Goldenseal: Time-Dependent Inhibition and Allosteric Effects. Drug metabolism and disposition: the biological fate of chemicals, 2020. Read 2026-10-23.
- Clinical evidence of herbal drugs as perpetrators of pharmacokinetic drug interactions. Planta medica, 2012. Read 2026-10-23.
- In vivo effects of goldenseal, kava kava, black cohosh, and valerian on human cytochrome P450 1A2, 2D6, 2E1, and 3A4/5 phenotypes. Clinical pharmacology and therapeutics, 2005. Read 2026-10-23.
- Pharmacokinetic of berberine, the main constituent of Berberis vulgaris L.: A comprehensive review. Phytotherapy research : PTR, 2022. Read 2026-10-23.
- The Pharmacokinetic Interaction Between Metformin and the Natural Product Goldenseal Is Metformin Dose-Dependent: A Three-Arm Crossover Study in Adults With Type 2 Diabetes. Clinical and translational science, 2025. Read 2026-10-23.
- Physiologically based pharmacokinetic model predictions of natural product-drug interactions between goldenseal, berberine, imatinib and bosutinib. European journal of clinical pharmacology, 2022. Read 2026-10-23.
- The clinical efficacy and safety of berberine in the treatment of non-alcoholic fatty liver disease: a meta-analysis and systematic review. Journal of translational medicine, 2024. Read 2026-10-23.
- The effect of berberine supplementation on obesity parameters, inflammation and liver function enzymes: A systematic review and meta-analysis of randomized controlled trials. Clinical nutrition ESPEN, 2020. Read 2026-10-23.
- Glucose-lowering effect of berberine on type 2 diabetes: A systematic review and meta-analysis. Frontiers in pharmacology, 2022. Read 2026-10-23.