Drug & supplement interaction

White Horehound + Glipizide, Metformin

Glipizide, Metformin brand name: Metaglip.

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

White Horehound has a moderate interaction with Glipizide, Metformin. Evidence from animal research suggests that white horehound might lower blood glucose.

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

White Horehound and Glipizide, Metformin

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

Moderate

ANTIDIABETES DRUGS

Why this applies to Glipizide, Metformin

Glipizide, Metformin falls under ANTIDIABETES DRUGS — the group White Horehound interacts with.

Evidence from animal research suggests that white horehound might lower blood glucose. However, preliminary clinical research suggests that white horehound only slightly lowers blood glucose when taken in combination with antidiabetic agents, suggesting that the effect may not be clinically significant. Until more is known, use with caution. Theoretically, white horehound may have additive effects when used by patients taking antidiabetic drugs. The dose of diabetes medications might need to be adjusted. Some antidiabetes drugs include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, metformin (Glucophage), pioglitazone (Actos), rosiglitazone (Avandia), and others.
Severity Moderate Likelihood Possible Evidence B

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: white horehound may nudge your blood sugar down a little on its own, and your Metaglip (glipizide plus metformin) is already doing that job. Put them together and the effects could stack, in theory leaving your blood sugar lower than expected. The glipizide part especially can cause low blood sugar, so watch for shakiness, sweating, dizziness, hunger, or feeling foggy.

That said, the human research we have is limited and suggests the extra drop is usually small and may not matter much. An occasional horehound cough drop is unlikely to be a problem. If you plan to take it regularly as a supplement, just give your pharmacist or doctor a heads-up and keep an eye on your home glucose readings. Don't change your diabetes dose on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Roman, Ramos R., Alarcon-Aguilar, F., Lara-Lemus, A., and Flores-Saenz, J. L. Hypoglycemic effect of plants used in Mexico as antidiabetics. Arch.Med.Res 1992;23:59-64.
  2. Novaes AP, Rossi C, Poffo C, et al. Preliminary evaluation of the hypoglycemic effect of some Brazilian medicinal plants. Therapie. 2001;56(4):427-30.
  3. Herrera-Arellano, A., Aguilar-Santamaria, L., Garcia-Hernandez, B., Nicasio-Torres, P., and Tortoriello, J. Clinical trial of Cecropia obtusifolia and Marrubium vulgare leaf extracts on blood glucose and serum lipids in type 2 diabetics. Phytomedicine 200 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

White Horehound Also Interacts With Other Medications

White Horehound has 257 moderate known drug interactions in our database — the Glipizide, Metformin one above is one of them. If you take anything else, check it against the full list below.

Moderate 257 No known interaction 2,573 (incl. Glipizide, Metformin)
Taking anything else?

Check Another of Your Medications Against White Horehound

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

Everything else you take

See Every Supplement That Interacts With Glipizide, Metformin

This page covers White Horehound only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Glipizide, Metformin page lists 307 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), Adrafinil (moderate) and African Wild Potato (moderate).

By severity: 2 major · 257 moderate · 48 minor.

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

“Glipizide and metformin (Metaglip) already work hard to pull blood sugar down, which is exactly why this list of 307 ingredients deserves genuine vigilance rather than a shrug. Most of them, 239, can lower glucose on their own, and stacked on this pill the combined effect can tip into true hypoglycemia.”

Reviewed by 2 · Jul 18, 2026

Open the Glipizide, Metformin interaction page

How much people look this up

Where White Horehound and Glipizide, 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 White Horehound
Steady interest

#1,036 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Glipizide, Metformin
Top half

#1,081 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 White Horehound

What is White Horehound?

White Horehound
  • Cough and chest congestion
  • Sore throat
  • Bronchitis
  • Digestive upset and poor appetite
  • Bloating and gas

White horehound is a traditional bitter herb used mainly for coughs, sore throats, and mild digestive complaints, and it is a common flavoring in old-fashioned cough drops. Solid human evidence supporting these uses is limited, so view it as a folk remedy rather than a proven treatment. Talk to your pharmacist or doctor before using it, and avoid it during pregnancy.

Read the full White Horehound monograph & all interactions
Keep checking

Other Drugs & White Horehound

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

0Major
257Moderate
0Minor
2,572No known interaction
257 Moderate 2,572 No interaction
Moderate

257 interactions

Showing 60 of 257 moderate interactions — see all 257 on the White Horehound page.

No interaction 2,572 drugs checked — show the list

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

Showing the 60 most looked-up of 2,572 medications checked with no known interaction — see the full White Horehound list.

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

Can you take White Horehound with Glipizide, Metformin?
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 White Horehound and Glipizide, Metformin 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 Glipizide, Metformin and White Horehound?

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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.