The short answer
Willow bark has not been shown to cause low blood sugar specifically with repaglinide. Its salicylate content warrants a product review, but it is not equivalent to aspirin.
What this answer covers
Willow bark; species and salicin content are not fully specified by this inventory name.
- Supplement or preparation
- Willow Bark
- Medication ingredient
- repaglinide
Why the label raises a question
Repaglinide labeling includes salicylates among drugs that may increase glucose lowering. Willow bark can produce salicylic acid after ingestion, but this does not establish the effect of a particular bark product.
What the human study measured
Ten volunteers took a standardized willow extract. Researchers measured salicylate exposure, which was much lower than after analgesic doses of synthetic salicylates. They did not measure repaglinide concentrations or low-blood-sugar events.
Avoid an aspirin equivalence assumption
Check the willow species, extract and salicin amount with the pharmacist. A bark dose should not be converted into an aspirin dose or treated as proven to have the same glucose effects.
Keep the prescribed medicine plan
Take repaglinide within thirty minutes before meals as prescribed and skip its dose when a meal is skipped. Review supplement changes with the prescriber instead of inventing a separation interval or adjusting the medicine yourself.
Watch for low blood sugar
Follow your existing glucose-monitoring and low-blood-sugar treatment plan. New sweating, shakiness, hunger or confusion warrants a glucose check when possible. Severe confusion, a seizure or inability to swallow safely needs emergency help.
Evidence and practical considerations
Side effects & toxicity
The exact label lists salicylates as potentially increasing glucose lowering, but transferring that to variable willow bark has limited support. Human willow pharmacokinetics confirms salicylic acid formation with comparatively low exposure, without a repaglinide or glucose endpoint.
- Exact scope
- Willow bark; species and salicin content are not fully specified by this inventory name. with Exact repaglinide oral tablets. Exact RxNorm IN73044 oral repaglinide; CYP2C8, CYP3A4 and transporters must not be equated with nateglinide pathways.
- Medication form and route
- oral
- Timing or duration
- Source-specific single-dose, repeated-dose and observational exposures distinguished.
What remains uncertain
- No direct pair trial or adverse-event rate. Salicin, salicylic acid and acetylsalicylic acid are not equivalent preparations; no species, dose or timing rule can be inferred.
Factors that may matter: preparation and plant part; clinical indication; dose; other medicines; baseline alertness.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed repaglinide.
Insulin secretagogue with hypoglycemia risk; within thirty minutes before meals and skip dose with skipped meal; nicotinic acid may reduce glucose-lowering effect, salicylates may increase it.
How this applies: Exact RxNorm IN73044 oral repaglinide; CYP2C8, CYP3A4 and transporters must not be equated with nateglinide pathways.
No universal supplement dose, interval, event rate or untested formulation equivalence.
Source 2: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Ten healthy volunteers.
Salicylic acid was the major circulating metabolite; exposure was much lower than with analgesic doses of synthetic salicylates.
How this applies: Only the named drug, preparation, route and measured endpoints apply.
No repaglinide or glucose endpoint; salicin is not aspirin and variable willow products cannot be assigned a pharmaceutical salicylate dose.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Research summary published | |
| Article prepared | |
| Current exact available claims adjudicated using original captures and explicit identity and comparator limits. |
Article revision: ed3c34fcac169a6f
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.