Drug & supplement interaction

Gymnema + Metformin, Rosiglitazone

Metformin, Rosiglitazone brand name: Avandamet.

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

Metformin, Rosiglitazone falls into 2 drug categories that Gymnema can interact with; the most serious is rated moderate. Theoretically, gymnema might increase or decrease levels of drugs metabolized by CYP2C9.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Gymnema and Metformin, Rosiglitazone

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Gymnema interacts with whole categories of medication. Metformin, Rosiglitazone falls into 2 of those categories, so it can interact with Gymnema in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

1 of 2

Why this applies to Metformin, Rosiglitazone

Metformin, Rosiglitazone falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES — the group Gymnema interacts with.

Theoretically, gymnema might increase or decrease levels of drugs metabolized by CYP2C9.
Animal research shows that gymnema can induce the CYP2C9 enzyme. In one animal study, gymnema caused a 2.4-fold increase in the clearance of tolbutamide, a CYP2C9 substrate, in rats. In vitro research also shows that gymnema can inhibit CYP2C9.
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 on combining gymnema with your Avandamet (metformin plus rosiglitazone). The rosiglitazone half is handled by a liver enzyme called CYP2C9, and gymnema may nudge that enzyme in either direction. In lab and animal studies it has both sped up and slowed down this enzyme, so the effect is honestly unpredictable. If it speeds things up, rosiglitazone could clear faster and work a little less well; if it slows things down, levels could creep up.

On top of that, gymnema itself may lower blood sugar. Stacked with these diabetes meds, the bigger real-world concern is your sugar dropping too low (shakiness, sweating, dizziness). This is theoretical and based on weak evidence, so don't panic, but please check your blood sugar and talk with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Rammohan B, Samit K, Chinmoy D, et al. Human cytochrome P450 enzyme modulation by gymnema sylvestre: a predictive safety evaluation by LC-MS/MS. Pharmacogn Mag. 2016 Jul;12(Suppl 4):S389-S394.
  2. Vaghela M, Sahu N, Kharkar P, Pandita N. In vivo pharmacokinetic interaction by ethanolic extract of gymnema sylvestre with CYP2C9 (tolbutamide), CYP3A4 (amlodipine) and CYP1A2 (phenacetin) in rats. Chem Biol Interact. 2017 Dec 25;278:141-151. PubMed
  3. Vaghela M, Iyer K, Pandita N. In vitro inhibitory effect of gymnema sylvestre extracts and total gymnemic acids fraction on select cytochrome P450 activities in rat liver microsomes. Eur J Drug Metab Pharmacokinet. 2017 Oct 10. PubMed
Moderate

ANTIDIABETES DRUGS

2 of 2

Metformin, Rosiglitazone also falls under ANTIDIABETES DRUGS.

Theoretically, taking gymnema with antidiabetes drugs might increase the risk of hypoglycemia.
Gymnema reduces blood glucose levels in some human and animal research. In human studies, it has been shown to enhance the blood glucose lowering effects of hypoglycemic drugs. However, other research in adults with prediabetes or metabolic syndrome suggests that gymnema does not reduce fasting levels of blood glucose. Until more is known, monitor blood glucose levels closely.
Severity Moderate Likelihood Probable Evidence B

Interaction 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..

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

Avandamet pairs two diabetes medicines: metformin and rosiglitazone. Both already work to bring your blood sugar down. Gymnema may also nudge blood sugar lower on its own, so taking them together can add up to a bigger drop than you expect. That raises your chance of going too low, which is called hypoglycemia.

Watch for shakiness, sweating, a racing heart, sudden hunger, confusion, or feeling lightheaded. The evidence here is moderate and a bit mixed (some studies show an effect, others don't), so this isn't a reason to panic. The practical move is to check your blood sugar more closely if you add gymnema, and let your pharmacist or doctor know before you start so they can guide any adjustments. Please don't change your medicine on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Shanmugasundaram ER, Rajeswari G, Baskaran K, et al. Use of Gymnema sylvestre leaf extract in the control of blood glucose in insulin-dependent diabetes mellitus. J Ethnopharmacol 1990;30:281-94. PubMed
  2. Baskaran K, Kizar Ahamath B, Radha Shanmugasundaram K, Shanmugasundaram ER. Antidiabetic effect of leaf extract from Gymnema sylvestre in non-insulin-dependent diabetes mellitus patients. J Ethnopharmacol 1990;30:295-300.
  3. Kamble B, Gupta A, Moothedath I, Khatal L, Janrao S, Jadhav A, et al. Effects of Gymnema sylvestre extract on the pharmacokinetics and pharmacodynamics of glimepiride in streptozotocin induced diabetic rats. Chem Biol Interact. 2016;245:30-8. PubMed
  4. Tiwari P, Mishra BN, Sangwan NS. Phytochemical and pharmacological properties of Gymnema sylvestre: an important medicinal plant. Biomed Res Int. 2014; 2014:830285.
  5. Fabio GD, Romanucci V, De Marco A, Zarrelli A. Triterpenoids from Gymnema sylvestre and their pharmacological activities. Molecules. 2014;19(8):10956-81. PubMed
  6. Zuniga LY, Gonzalez-Ortiz M, Martinez-Abundis E. Effect of gymnema sylvestre administration on metabolic syndrome, insulin sensitivity, and insulin secretion. J Med Food. 2017 Aug;20(8):750-54.
  7. Gaytán Martínez LA, Sánchez-Ruiz LA, Zuñiga LY, González-Ortiz M, Martínez-Abundis E. Effect of Gymnema sylvestre administration on glycemic control, insulin secretion, and insulin sensitivity in patients with impaired glucose tolerance. J Med Food. 2021;

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

Gymnema Also Interacts With Other Medications

Gymnema has 346 moderate, 504 minor known drug interactions in our database — the Metformin, Rosiglitazone one above is among them. If you take anything else, check it against the full list below.

Moderate 346 Minor 504 No known interaction 1,980 (incl. Metformin, Rosiglitazone)
Taking anything else?

Check Another of Your Medications Against Gymnema

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

Everything else you take

See Every Supplement That Interacts With Metformin, Rosiglitazone

This page covers Gymnema only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metformin, Rosiglitazone page lists 315 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Siberian Cocklebur (major), Wine (major) and Acai (moderate).

By severity: 4 major · 268 moderate · 43 minor.

From our pharmacist’s overview on the Metformin, Rosiglitazone page

“Avandamet pairs metformin with rosiglitazone to manage type 2 diabetes, and its supplement list calls for genuine care rather than a quick skim. Start with the four major-rated entries: alcohol and the herb Siberian cocklebur can each stress the liver, a serious concern with rosiglitazone on board, while activated charcoal can soak up…”

Reviewed by 2 · Jul 18, 2026

Open the Metformin, Rosiglitazone interaction page

One more smart check

Taking Gymnema as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1,084 real supplement products containing Gymnema, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Gymnema. Your product may carry other ingredients that interact with Metformin, Rosiglitazone too, on top of Gymnema — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Gymnema and Metformin, Rosiglitazone 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 Gymnema
Top 25%

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

29 days ago today
Medication Metformin, Rosiglitazone
Steady interest

#1,507 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 Gymnema

What is Gymnema?

Gymnema
  • Blood sugar support
  • Type 2 diabetes
  • Sugar cravings
  • Weight management
  • Cholesterol support

Gymnema is an Ayurvedic herb best known for possibly helping lower blood sugar and reducing the taste of sweetness on the tongue. Some early human studies are encouraging for blood sugar support, but the evidence is still limited and not strong enough to replace standard treatment. If you have diabetes or take other medicines, talk with your pharmacist or doctor before using it.

Read the full Gymnema monograph & all interactions
Keep checking

Other Drugs & Gymnema

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

0Major
346Moderate
504Minor
1,979No known interaction
346 Moderate 504 Minor 1,979 No interaction
Moderate

346 interactions

Showing 60 of 346 moderate interactions — see all 346 on the Gymnema page.

Minor

504 interactions

Showing 60 of 504 minor interactions — see all 504 on the Gymnema page.

No interaction 1,979 drugs checked — show the list

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

Showing the 60 most looked-up of 1,979 medications checked with no known interaction — see the full Gymnema list.

See the full Gymnema interactions page
See every supplement checked against Metformin, Rosiglitazone, 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
Gymnema monograph › Uses, safety, and every drug interaction in one place Metformin, Rosiglitazone supplement interactions › Every supplement checked against Metformin, Rosiglitazone, 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 Gymnema and Metformin, Rosiglitazone Together: Common Questions

Can you take Gymnema with Metformin, Rosiglitazone?
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.
Why are there 2 interactions listed for Gymnema and Metformin, Rosiglitazone?
Metformin, Rosiglitazone belongs to more than one drug category, and Gymnema interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Gymnema and Metformin, Rosiglitazone 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

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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.