Is Bilberry Safe with Metformin?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Monitor blood glucose levels more frequently when combining bilberry with metformin. Watch for symptoms of hypoglycemia such as dizziness, sweating, shakiness, or confusion. Inform your diabetes care team before starting bilberry.
Why this interaction occurs
Bilberry fruit and leaf extracts have demonstrated hypoglycemic properties in animal and limited human studies, potentially through improved insulin sensitivity and inhibition of alpha-glucosidase. Combined use with metformin may produce additive glucose-lowering effects increasing hypoglycemia risk.
Evidence
Evidence level: moderate.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 432,898 reports mentioning Metformin. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Metformin + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All Bilberry interactions → · All Metformin interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.