Drug & supplement interaction

Winter Cherry + Metformin Hydrochloride

Metformin Hydrochloride brand name: Riomet ER.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Winter Cherry has a moderate interaction with Metformin Hydrochloride. In animal diabetic models, winter cherry extract decreases blood glucose.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Winter Cherry and Metformin Hydrochloride

Here is the interaction we found between these two, with the evidence behind it.

Moderate

ANTIDIABETES DRUGS

Why this applies to Metformin Hydrochloride

Metformin Hydrochloride falls under ANTIDIABETES DRUGS — the group Winter Cherry interacts with.

In animal diabetic models, winter cherry extract decreases blood glucose. This effect has not been shown in humans. Theoretically, winter cherry might have additive effects with antidiabetes drugs and increase the risk of hypoglycemia.
Some antidiabetes drugs include glimepiride (Amaryl), glyburide (Diabeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), and others.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the short version: in animal studies, Winter Cherry (ashwagandha) seemed to lower blood sugar a bit on its own. Since your metformin is already working to bring your glucose down, stacking the two could, in theory, push your numbers lower than expected. That might show up as shakiness, sweating, dizziness, hunger, or feeling confused or weak if your sugar drops too far.

I want to be honest about the evidence, though. This blood sugar effect has only been seen in lab and animal research, not proven in people, so it's more of a theoretical caution than a sure thing. If you'd like to try Winter Cherry, that's a fine conversation to have, just check your glucose a little more closely at first and let your doctor or pharmacist know so we can keep an eye on it together.

Contact Dr. Brian directly if you have additional questions on this interaction

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Winter Cherry Also Interacts With Other Medications

Winter Cherry has 155 moderate known drug interactions in our database — the Metformin Hydrochloride one above is one of them. If you take anything else, check it against the full list below.

Moderate 155 No known interaction 2,675 (incl. Metformin Hydrochloride)
Taking anything else?

Check Another of Your Medications Against Winter Cherry

Covers the 2,830 medications we’ve checked against Winter Cherry. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Metformin Hydrochloride

This page covers Winter Cherry only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metformin Hydrochloride page lists 257 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Siberian Cocklebur (major), Acai (moderate), African Wild Potato (moderate) and Agaricus Mushroom (moderate).

By severity: 2 major · 217 moderate · 38 minor.

From our pharmacist’s overview on the Metformin Hydrochloride page

“Anyone taking metformin hydrochloride (Riomet ER) should treat this list with genuine care, because two of its 257 entries are rated major. Siberian cocklebur has caused severe hypoglycemia in people and should not be combined with metformin at all, and activated charcoal can adsorb the drug in the gut so less reaches your blood.”

Reviewed by 2 · Jul 18, 2026

Open the Metformin Hydrochloride interaction page

How much people look this up

Where Winter Cherry and Metformin Hydrochloride Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Winter Cherry
Steady interest

#1,071 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Metformin Hydrochloride
Top 10%

#144 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Winter Cherry

What is Winter Cherry?

  • Stress and anxiety
  • Fatigue and low energy
  • Sleep support
  • General vitality and tonic
  • Athletic performance

Winter Cherry is another name for ashwagandha (Withania somnifera), an herb long used in Ayurvedic medicine, most often for stress, sleep, and energy. Some small studies suggest it may help with stress and anxiety, but the evidence is still limited and not definitive. It is generally well tolerated short-term, but pregnant women should avoid it, and anyone with a health condition should check with a pharmacist or doctor first.

Read the full Winter Cherry monograph & all interactions
Keep checking

Other Drugs & Winter Cherry

Browse every other medication we’ve checked against Winter Cherry — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
155Moderate
0Minor
2,674No known interaction
155 Moderate 2,674 No interaction
Moderate

155 interactions

Showing 60 of 155 moderate interactions — see all 155 on the Winter Cherry page.

No interaction 2,674 drugs checked — show the list

We also checked Winter Cherry against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,674 medications checked with no known interaction — see the full Winter Cherry list.

See the full Winter Cherry interactions page
See every supplement checked against Metformin Hydrochloride, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Winter Cherry monograph › Uses, safety, and every drug interaction in one place Metformin Hydrochloride supplement interactions › Every supplement checked against Metformin Hydrochloride, ranked by severity Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Winter Cherry and Metformin Hydrochloride Together: Common Questions

Can you take Winter Cherry with Metformin Hydrochloride?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Winter Cherry and Metformin Hydrochloride interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Metformin Hydrochloride and Winter Cherry?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.