Drug & supplement interaction

Guava + Insulin Glargine (rDNA)

Insulin Glargine (rDNA) brand name: Lantus.

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

Guava has a moderate interaction with Insulin Glargine (rDNA). Theoretically, concomitant use with antidiabetes drugs might have additive effects and increase the risk of hypoglycemia.

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

Guava and Insulin Glargine (rDNA)

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

Moderate

ANTIDIABETES DRUGS

Why this applies to Insulin Glargine (rDNA)

Insulin Glargine (rDNA) falls under ANTIDIABETES DRUGS — the group Guava interacts with.

Theoretically, concomitant use with antidiabetes drugs might have additive effects and increase the risk of hypoglycemia. Animal research shows that guava leaf extract or guava fruit can have hypoglycemic effects. Monitor blood glucose levels closely. Medication dose adjustments may be necessary. Some antidiabetes drugs include glimepiride (Amaryl), glyburide (Diabeta, Glynase PresTab, Micronase), insulin, metformin, 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 simple version: Lantus (insulin glargine) is your long-acting insulin that keeps your blood sugar steady through the day and night. Guava leaf, in lab and animal studies, has shown a mild blood-sugar-lowering effect of its own. So if you add a concentrated guava leaf supplement on top of your insulin, the two could stack up and push your sugar lower than you want.

What that can feel like: shakiness, sweating, dizziness, a racing heart, or confusion (the usual signs of a low). I want to stress that this is mostly theoretical right now, and eating guava as a fruit is unlikely to cause trouble. Still, if you want to try guava leaf products, check with your pharmacist or doctor first and keep an eye on your glucose readings.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Gutiérrez RM, Mitchell S, Solis RV. Psidium guajava: a review of its traditional uses, phytochemistry and pharmacology. J Ethnopharmacol. 2008;117(1):1-27. PubMed

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

Guava Also Interacts With Other Medications

Guava has 85 moderate known drug interactions in our database — the Insulin Glargine (rDNA) one above is one of them. If you take anything else, check it against the full list below.

Moderate 85 No known interaction 2,745 (incl. Insulin Glargine (rDNA))
Taking anything else?

Check Another of Your Medications Against Guava

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

Everything else you take

See Every Supplement That Interacts With Insulin Glargine (rDNA)

This page covers Guava only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Insulin Glargine (rDNA) page lists 242 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 2 major · 211 moderate · 29 minor.

From our pharmacist’s overview on the Insulin Glargine (rDNA) page

“This page for insulin glargine (Lantus) runs to 242 ingredients, and it earns real care, because nearly everything on it moves blood sugar while your basal insulin dose stays fixed. Most add to the glucose-lowering effect and raise the odds of a low.”

Reviewed by 2 · Jul 18, 2026

Open the Insulin Glargine (rDNA) interaction page

One more smart check

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

We hold 484 real supplement products containing Guava, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Guava. Your product may carry other ingredients that interact with Insulin Glargine (rDNA) too, on top of Guava — 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 Guava and Insulin Glargine (rDNA) 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 Guava
Top half

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

29 days ago today
Medication Insulin Glargine (rDNA)
Steady interest

#1,940 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 Guava

What is Guava?

  • Diarrhea and digestive upset
  • Blood sugar support
  • Cholesterol support
  • Wound and skin care
  • Cough and sore throat

Guava is a tropical fruit tree whose leaves and fruit have a long history of folk use for diarrhea, blood sugar, and general wellness. The fruit is a nutritious food rich in vitamin C, but evidence for guava leaf supplements treating specific health conditions is limited and mostly early. If you want to try guava leaf products, talk with your pharmacist or doctor first, especially if you take medicines or have a health condition.

Read the full Guava monograph & all interactions
Medication

About Insulin Glargine (rDNA origin) Injection

What Is Insulin Glargine (rDNA origin) Injection Used For?

Brand name: Lantus

Insulin glargine is used to improve glycemic control (blood sugar management) in adults and pediatric patients with type 1 diabetes mellitus, and in adults with type 2 diabetes mellitus. It is a long-acting basal insulin, meaning it works gradually over the course of the day to keep blood sugar steady.

Insulin glargine is not recommended for treating diabetic ketoacidosis (a serious complication where the blood becomes dangerously acidic).

See full Insulin Glargine (rDNA origin) Injection drug information
Keep checking

Other Drugs & Guava

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

0Major
85Moderate
0Minor
2,744No known interaction
85 Moderate 2,744 No interaction
Moderate

85 interactions

Showing 60 of 85 moderate interactions — see all 85 on the Guava page.

No interaction 2,744 drugs checked — show the list

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

Showing the 60 most looked-up of 2,744 medications checked with no known interaction — see the full Guava list.

See the full Guava interactions page
See every supplement checked against Insulin Glargine (rDNA), 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
Guava monograph › Uses, safety, and every drug interaction in one place Insulin Glargine (rDNA) supplement interactions › Every supplement checked against Insulin Glargine (rDNA), ranked by severity Insulin Glargine (rDNA origin) Injection 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 Guava and Insulin Glargine (rDNA) Together: Common Questions

Can you take Guava with Insulin Glargine (rDNA)?
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 Guava and Insulin Glargine (rDNA) 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 Insulin Glargine (rDNA) and Guava?

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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.