Drug & supplement interaction

Guava + Insulin (Human)

Insulin (Human) brand names: Novolin N, Novolin 70/30, Novolin R, Novolin L, Afrezza.

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

Guava has a moderate interaction with Insulin (Human). 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 (Human)

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

Moderate

ANTIDIABETES DRUGS

Why this applies to Insulin (Human)

Insulin (Human) 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: insulin already lowers your blood sugar, and guava (especially concentrated guava leaf supplements) may nudge your blood sugar down a little too. Put them together and those effects could stack up, which means you might dip lower than expected. Watch for the usual signs of low blood sugar, like shakiness, sweating, dizziness, a racing heart, confusion, or feeling suddenly hungry.

I want to be honest about the strength of this concern, though. The evidence here comes mostly from lab and animal studies, so it's more of a theoretical caution than a proven problem. Eating guava fruit as food is unlikely to throw things off much. If you're thinking about a guava leaf supplement, check your numbers more often and talk with your pharmacist or doctor before starting, since your insulin dose may need a look.

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 (Human) 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 (Human))
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 (Human)

This page covers Guava only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Insulin (Human) page lists 259 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 3 major · 218 moderate · 38 minor.

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

“With human insulin (Novolin, Afrezza), extra glucose lowering is not a nuisance, it is the hazard itself, and this is one of the lists I treat as genuinely serious. Nearly every ingredient here either drops blood sugar on its own or adds to insulin's effect, and the combination can push a normal dose into hypoglycemia, a dangerous low.”

Reviewed by 2 · Jul 18, 2026

Open the Insulin (Human) 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 (Human) 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 (Human) 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

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

29 days ago today
Medication Insulin (Human)
Top 10%

#213 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 Human Insulin Injection

What Is Human Insulin Injection Used For?

Brand names: Novolin N, Novolin 70/30, Novolin R, Novolin L, Afrezza

Novolin (human insulin injection) is used to improve glycemic control — meaning blood sugar management — in adults and children with diabetes mellitus.

Novolin 70/30 is a fixed-ratio mixture of intermediate-acting and short-acting human insulin. Because the ratio is fixed, it cannot be adjusted separately for background (basal) or mealtime (prandial) needs.

See full Human Insulin 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 (Human), 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 (Human) supplement interactions › Every supplement checked against Insulin (Human), ranked by severity Human Insulin 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 (Human) Together: Common Questions

Can you take Guava with Insulin (Human)?
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 (Human) 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 (Human) 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.