Drug & supplement interaction

Cola Nut + Metformin

Metformin brand names: Glucophage, Metformin.

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

Metformin falls into 2 drug categories that Cola Nut can interact with; the most serious is rated minor. Theoretically, taking cola nut with antidiabetes drugs might interfere with blood glucose control.

Read the full interaction report
SeverityMinor
LikelihoodUnlikely
Interactions2
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Cola Nut and Metformin

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

Why Are There 2 Interactions?

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

Minor

ANTIDIABETES DRUGS

1 of 2

Why this applies to Metformin

Metformin falls under ANTIDIABETES DRUGS — the group Cola Nut interacts with.

Theoretically, taking cola nut with antidiabetes drugs might interfere with blood glucose control.
Cola nut contains caffeine. Some conflicting reports claim that caffeine might increase or decrease blood sugar.
Severity Minor Likelihood Unlikely Evidence B

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

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

Here's the simple version: cola nut is basically a natural source of caffeine, and caffeine can nudge your blood sugar around a little. The tricky part is that the research doesn't agree on which direction. Some reports suggest caffeine slightly raises blood sugar, others suggest it can lower it. Metformin itself isn't changed by cola nut (it isn't broken down by the liver the way many drugs are), so this isn't about metformin building up or wearing off. It's just that caffeine may make your sugar numbers a touch less steady.

The good news is this interaction is rated minor and unlikely, and the evidence behind it is weak. An occasional cola drink probably won't matter. If you regularly use concentrated cola nut supplements or lots of caffeine, mention it to your pharmacist or doctor and keep an eye on your readings.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Watson JM, Jenkins EJ, Hamilton P, et al. Influence of caffeine on the frequency and perception of hypoglycemia in free-living patients with type 1 diabetes. Diabetes Care 2000;23:455-9. PubMed
  2. Bell DG, Jacobs I, Ellerington K. Effect of caffeine and ephedrine ingestion on anaerobic exercise performance. Med Sci Sports Exerc 2001;33:1399-403. PubMed
Minor

METFORMIN (Glucophage)

2 of 2
Theoretically, metformin might increase the levels and adverse effects of the caffeine in cola nut.
Cola nut contains caffeine. Animal research suggests that metformin can reduce caffeine metabolism.
Severity Minor 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 thing about pairing cola nut with metformin: the concern isn't really about your blood sugar control. It's the other way around. Cola nut is basically a caffeine source, and some early animal research hints that metformin may slow down how your body clears that caffeine. If caffeine lingers longer, you might notice more of the usual caffeine effects, like jitteriness, a faster or pounding heartbeat, trouble sleeping, or feeling wired.

I want to be honest that this is a theoretical and minor interaction based only on lab and animal data, so it's not something I'd lose sleep over. Most people do fine. Still, if you take metformin and find caffeine hits you harder than expected, ease up on cola nut and chat with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mohiuddin, M., Azam, A. T., Amran, M. S., and Hossain, M. A. In vive effects of gliclazide and metformin on the plasma concentration of caffeine in healthy rats. Pak.J Biol Sci 5-1-2009;12(9):734-737.

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

Cola Nut Also Interacts With Other Medications

Cola Nut has 547 moderate, 107 minor known drug interactions in our database — the Metformin one above is among them. If you take anything else, check it against the full list below.

Moderate 547 Minor 107 No known interaction 2,176 (incl. Metformin)
Taking anything else?

Check Another of Your Medications Against Cola Nut

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

From our Q&A

Questions About Cola Nut or Metformin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Cola Nut or Metformin, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Metformin

This page covers Cola Nut only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metformin page lists 258 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 · 39 minor.

From our pharmacist’s overview on the Metformin page

“Siberian cocklebur is the ingredient I most want anyone taking metformin (Glucophage) to know about. It has caused severe low blood sugar in people, documented in humans, and it should not be combined with any glucose-lowering medication.”

Reviewed by 2 · Jul 18, 2026

Open the Metformin interaction page

One more smart check

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

We hold 2 real supplement products containing Cola Nut, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cola Nut. Your product may carry other ingredients that interact with Metformin too, on top of Cola Nut — 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 Cola Nut and Metformin 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 Cola Nut
Steady interest

#1,051 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Metformin
Top 1%

#29 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 Cola Nut

What is Cola Nut?

Cola Nut
  • Energy and alertness
  • Mental focus
  • Physical performance
  • Weight loss support
  • Traditional digestive aid

Cola nut is a caffeine-containing seed from West Africa used mainly as a natural stimulant for energy and alertness. Most of its effects come from caffeine, and strong human evidence for specific health benefits is limited. Because of its caffeine content, people sensitive to stimulants and those who are pregnant or have heart conditions should be cautious.

Read the full Cola Nut monograph & all interactions
Medication

About Metformin

What Is Metformin Used For?

Brand names: Glucophage, Metformin

Metformin is used to improve blood sugar (glucose) control in people with type 2 diabetes mellitus. It is always used together with diet and exercise, not instead of them.

Metformin hydrochloride tablets and oral solution are approved for adults and children 10 years and older. Metformin hydrochloride extended-release tablets — including brands such as Fortamet, Glumetza, and Metformin Hydrochloride Extended Release — are approved for adults only.

See full Metformin drug information
Keep checking

Other Drugs & Cola Nut

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

0Major
547Moderate
107Minor
2,175No known interaction
547 Moderate 107 Minor 2,175 No interaction
Moderate

547 interactions

Showing 60 of 547 moderate interactions — see all 547 on the Cola Nut page.

Minor

107 interactions

Showing 60 of 107 minor interactions — see all 107 on the Cola Nut page.

No interaction 2,175 drugs checked — show the list

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

Showing the 60 most looked-up of 2,175 medications checked with no known interaction — see the full Cola Nut list.

See the full Cola Nut interactions page
See every supplement checked against Metformin, 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
Cola Nut monograph › Uses, safety, and every drug interaction in one place Metformin supplement interactions › Every supplement checked against Metformin, ranked by severity Metformin drug information › The full plain-English guide to this medication 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 Cola Nut and Metformin Together: Common Questions

Can you take Cola Nut with Metformin?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 2 interactions listed for Cola Nut and Metformin?
Metformin belongs to more than one drug category, and Cola Nut 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 Cola Nut and Metformin interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Metformin and Cola Nut?

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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.