Drug & supplement interaction

Black Tea + Linagliptin, Metformin Hydrochloride

Linagliptin, Metformin Hydrochloride brand name: Jentadueto XR.

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

Linagliptin, Metformin Hydrochloride falls into 2 drug categories that Black Tea can interact with; the most serious is rated minor. Theoretically, taking black tea 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

Black Tea and Linagliptin, Metformin Hydrochloride

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

Why Are There 2 Interactions?

Black Tea interacts with whole categories of medication. Linagliptin, Metformin Hydrochloride falls into 2 of those categories, so it can interact with Black Tea 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 Linagliptin, Metformin Hydrochloride

Linagliptin, Metformin Hydrochloride falls under ANTIDIABETES DRUGS — the group Black Tea interacts with.

Theoretically, taking black tea with antidiabetes drugs might interfere with blood glucose control.
Black tea contains caffeine. Reports claim that caffeine might increase or decrease blood sugar levels. Also, some evidence in healthy individuals suggests that drinking black tea reduces 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: your Jentadueto XR (a combo of linagliptin and metformin) works to lower your blood sugar, and black tea might nudge those numbers a little. The caffeine in tea can push blood sugar slightly up or down depending on the person, while the tea's plant compounds may modestly lower it. Honestly, this is mostly theoretical and the evidence is weak, so for most people enjoying a cup or two it isn't a big deal.

What I'd watch for: if you notice shakiness, sweating, or unusually high readings around heavy tea drinking, that's worth tracking. Neither of these drugs is a prodrug, and black tea doesn't really change how your body clears them. Just keep an eye on your glucose log and chat with your pharmacist or doctor before making any changes.

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
  3. Bahorun T, Luximon-Ramma A, Neergheen-Bhujun VS, Gunness TK, Googoolye K, Auger C, Crozier A, Aruoma OI. The effect of black tea on risk factors of cardiovascular disease in a normal population. Prev Med. 2012 ;54 Suppl:S98-102. PubMed
Minor

Metformin (Glucophage)

2 of 2
Theoretically, metformin might increase the levels and adverse effects of caffeine.
Black tea contains caffeine. Animal research suggests that metformin can reduce caffeine metabolism. Theoretically, concomitant use can increase caffeine serum concentrations and the risk of caffeine adverse effects.
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 gist with your Jentadueto XR (which combines linagliptin and metformin) and your daily cup of black tea. The interaction on file isn't about the tea changing how your diabetes medicine works. It's actually the other way around: the metformin part may slow down how your body clears caffeine from the tea. In theory, that caffeine could hang around a little longer and stack up.

If that happens, you might notice more caffeine-type effects, like feeling jittery, a faster heartbeat, trouble sleeping, or a touch more anxiety. I want to be honest though: this is based only on lab and animal research, so it's mostly theoretical and rated as minor. Most people drinking a normal amount of tea won't notice anything. If you're caffeine-sensitive or feel wired, just cut back a bit and check in 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

Black Tea Also Interacts With Other Medications

Black Tea has 8 major, 572 moderate, 113 minor known drug interactions in our database — the Linagliptin, Metformin Hydrochloride one above is among them. If you take anything else, check it against the full list below.

Major 8 Moderate 572 Minor 113 No known interaction 2,137 (incl. Linagliptin, Metformin Hydrochloride)
Taking anything else?

Check Another of Your Medications Against Black Tea

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

Everything else you take

See Every Supplement That Interacts With Linagliptin, Metformin Hydrochloride

This page covers Black Tea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Linagliptin, Metformin Hydrochloride page lists 285 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Siberian Cocklebur (major), St. John's Wort (major), Acai (moderate) and Adrafinil (moderate).

By severity: 3 major · 242 moderate · 40 minor.

From our pharmacist’s overview on the Linagliptin, Metformin Hydrochloride page

“Someone taking Jentadueto XR (linagliptin and metformin) for type 2 diabetes is often the same person eyeing fenugreek, bitter melon, or gymnema, and that overlap is why this page deserves real caution. Of its 285 ingredients, 239 can lower blood sugar on their own, so stacking them on a drug already doing that job risks pushing glucos…”

Reviewed by 2 · Jul 18, 2026

Open the Linagliptin, Metformin Hydrochloride interaction page

One more smart check

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

We hold 271 real supplement products containing Black Tea, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Black Tea. Your product may carry other ingredients that interact with Linagliptin, Metformin Hydrochloride too, on top of Black Tea — 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 Black Tea and Linagliptin, 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 Black Tea
Top 25%

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

29 days ago today
Medication Linagliptin, Metformin Hydrochloride
Steady interest

#1,815 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 Black Tea

What is Black Tea?

  • Mental alertness and energy
  • Heart health support
  • Blood pressure and cholesterol
  • Digestive complaints
  • Weight management
  • Antioxidant support

Black tea is a popular caffeinated drink made from the fully oxidized leaves of the Camellia sinensis plant, and it contains caffeine and antioxidant plant compounds. Moderate tea drinking is generally safe for most adults and may modestly support heart health and alertness, but it is not a proven treatment for any disease. If you are pregnant, breastfeeding, sensitive to caffeine, or taking medicines, talk to your pharmacist or doctor.

Read the full Black Tea monograph & all interactions
Keep checking

Other Drugs & Black Tea

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

8Major
572Moderate
113Minor
2,136No known interaction
8 Major 572 Moderate 113 Minor 2,136 No interaction
Major

8 interactions

Moderate

572 interactions

Showing 60 of 572 moderate interactions — see all 572 on the Black Tea page.

Minor

113 interactions

Showing 60 of 113 minor interactions — see all 113 on the Black Tea page.

No interaction 2,136 drugs checked — show the list

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

Showing the 60 most looked-up of 2,136 medications checked with no known interaction — see the full Black Tea list.

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

Can you take Black Tea with Linagliptin, Metformin Hydrochloride?
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 Black Tea and Linagliptin, Metformin Hydrochloride?
Linagliptin, Metformin Hydrochloride belongs to more than one drug category, and Black Tea 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 Black Tea and Linagliptin, Metformin Hydrochloride 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

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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.