May increase drug levels
In vitro only. Discuss with a prescriber before combining.
May increase drug levels
In vitro only. Discuss with a prescriber before combining.
Increased tacrolimus exposure
Do not combine without therapeutic drug monitoring.
Additive glucose reduction
Monitor blood glucose.
Claims about berberine and CYP2C9, and about berberine and bleeding risk with antiplatelet or anticoagulant drugs, were removed from this table. In the microsomal study above, CYP2C9 inhibition was attributed to a different goldenseal alkaloid, (-)-beta-hydrastine, not to berberine. No source located for this page evaluates bleeding risk with berberine plus antiplatelet drugs. Evidence is insufficient in both cases.
Analysis of 15 berberine dietary supplements bought from US vendors found average berberine content of 75% ± 25% of the label claim, with product potency ranging from 33% to 100%. Nine of the 15 products (60%) failed the 90% to 110% potency standard commonly applied to pharmaceutical preparations, and measured potency showed no association with product cost (Funk 2018, PMID: 28792254). Third-party testing is worth looking for. The previous claim on this page about testing in France was unsourced and has been removed.
Not Prohibited.
Analysis of 15 berberine dietary supplements bought from US vendors found average berberine content of 75% ± 25% of the label claim, with product potency ranging from 33% to 100%. Nine of the 15 products (60%) failed the 90% to 110% potency standard commonly applied to pharmaceutical preparations, and measured potency showed no association with product cost (Funk 2018, PMID: 28792254). Third-party testing is worth looking for. The previous claim on this page about testing in France was unsourced and has been removed.
Independently graded against 178,763 indexed supplements and 757 reviewed supplement and medication pairs, sourced from PubMed, FDA CAERS, openFDA, and NIH DSLD | Last updated: August 24, 2026
Not medical advice. Based on published clinical research and systematic reviews.
Safety
Metformin
Co-administration of berberine and metformin can lead to an additive hypoglycemic effect, increasing the risk of hypoglycemia.
Berberine inhibits the transport activity of organic cation transporters (OCT1 and OCT2), which govern the disposition of metformin, thereby increasing the plasma concentration and systemic exposure of metformin.
Hypoglycemia risk. Monitor blood glucose. Consider drug-interaction effects via inhibited CYPs.
Both activate AMPK. Berberine also inhibits CYP3A4/2D6/2C9. Additive hypoglycemic effect plus altered metabolism of other drugs.
SourcePMID 37439907
CYP2D6 substrates (codeine, tramadol, many antidepressants)
Theoretical mild interaction. Clinically minor at supplement doses.
Berberine has weak CYP2D6 and CYP3A4 inhibitory effects in vitro. Metoprolol pharmacokinetic interaction theoretical.
Theoretical mild interaction. Clinically minor at supplement doses.
Berberine has weak CYP2D6 and CYP3A4 inhibitory effects in vitro. Carvedilol pharmacokinetic interaction theoretical.
Theoretical mild interaction. Clinically minor at supplement doses.
Berberine has weak CYP2D6 and CYP3A4 inhibitory effects in vitro. Propranolol pharmacokinetic interaction theoretical.
Theoretical mild interaction. Clinically minor at supplement doses.
Berberine has weak CYP2D6 and CYP3A4 inhibitory effects in vitro. Nebivolol pharmacokinetic interaction theoretical.
CYP3A4 substrates (statins, calcium channel blockers)
Additive BP lowering and minor pharmacokinetic shift. Monitor blood pressure when starting or stopping berberine in losartan users.
Berberine has demonstrated mild blood pressure lowering effects and modulates CYP2C9 and CYP3A4 in vitro. Combined effect with losartan can be additive (BP) and pharmacokinetic (metabolite ratio shift).
Theoretical mild interaction. Clinically minor at supplement doses.
Berberine has weak CYP2D6 and CYP3A4 inhibitory effects in vitro. Bisoprolol pharmacokinetic interaction theoretical.
SourcePMID 37439907
Blood pressure medications
Additive blood pressure lowering possible. May be beneficial in some patients but increases risk of hypotension, especially at initiation or dose changes of either agent.
Berberine has demonstrated mild blood pressure lowering effects in clinical trials, likely through endothelial nitric oxide modulation and additive RAAS effects. Co-administration with lisinopril may produce additive blood pressure reduction.
Additive BP lowering and minor pharmacokinetic shift. Monitor blood pressure when starting or stopping berberine in losartan users.
Berberine has demonstrated mild blood pressure lowering effects and modulates CYP2C9 and CYP3A4 in vitro. Combined effect with losartan can be additive (BP) and pharmacokinetic (metabolite ratio shift).
Theoretical mild interaction. Clinically minor at supplement doses.
Berberine has weak CYP2D6 and CYP3A4 inhibitory effects in vitro. Metoprolol pharmacokinetic interaction theoretical.
Theoretical mild interaction. Clinically minor at supplement doses.
Berberine has weak CYP2D6 and CYP3A4 inhibitory effects in vitro. Carvedilol pharmacokinetic interaction theoretical.
Theoretical mild interaction. Clinically minor at supplement doses.
Berberine has weak CYP2D6 and CYP3A4 inhibitory effects in vitro. Propranolol pharmacokinetic interaction theoretical.
Theoretical mild interaction. Clinically minor at supplement doses.
Berberine has weak CYP2D6 and CYP3A4 inhibitory effects in vitro. Nebivolol pharmacokinetic interaction theoretical.
Theoretical mild interaction. Clinically minor at supplement doses.
Berberine has weak CYP2D6 and CYP3A4 inhibitory effects in vitro. Bisoprolol pharmacokinetic interaction theoretical.
Cyclosporine
Sulfonylureas (glipizide, glyburide)
Anticoagulants
Educational information only. This is not medical advice. These statements have not been evaluated by the FDA. Talk to your prescriber before starting, stopping, or combining any supplement with prescription medication.