Drug & supplement interaction

Rosemary + Metformin

Metformin brand names: Glucophage, Metformin.

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

Rosemary has a moderate interaction with Metformin. Theoretically, taking rosemary with antidiabetes drugs might increase the risk of hypoglycemia.

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

Rosemary and Metformin

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

Moderate

ANTIDIABETES DRUGS

Why this applies to Metformin

Metformin falls under ANTIDIABETES DRUGS — the group Rosemary interacts with.

Theoretically, taking rosemary with antidiabetes drugs might increase the risk of hypoglycemia.
Animal research shows that rosemary extract can decrease blood glucose levels in diabetic models. However, research in humans is conflicting. Although rosemary powder decreased blood glucose levels in healthy adults, no change in blood glucose levels was seen in adults with type 2 diabetes, most of whom were taking antidiabetes drugs.
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: rosemary may have a mild blood sugar lowering effect of its own. When you stack that on top of metformin, the two could in theory pull your glucose down a little more than expected. That might show up as low blood sugar symptoms like shakiness, sweating, dizziness, or feeling unusually tired or hungry.

That said, I want to keep this in perspective. Metformin alone rarely causes serious lows, and the human evidence on rosemary is mixed. In one study of people with type 2 diabetes, rosemary didn't change their numbers at all. Sprinkling it on your food is no concern. Concentrated rosemary capsules are where I'd be a bit more cautious, so check with your pharmacist before starting one.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bakirel, T., Bakirel, U., Keles, O. U., Ulgen, S. G., and Yardibi, H. In vivo assessment of antidiabetic and antioxidant activities of rosemary (Rosmarinus officinalis) in alloxan-diabetic rabbits. J Ethnopharmacol 2-28-2008;116(1):64-73. PubMed
  2. Erenmemisoglu, A., Saraymen, R., and Ustun, S. Effect of a Rosmarinus officinalis leave extract on plasma glucose levels in normoglycaemic and diabetic mice. Pharmazie 1997;52(8):645-646.
  3. Quirarte-Báez SM, Zamora-Perez AL, Reyes-Estrada CA, et al. A shortened treatment with rosemary tea (rosmarinus officinalis) instead of glucose in patients with diabetes mellitus type 2 (TSD). J Popul Ther Clin Pharmacol. 2019;26(4):e18-e28.
  4. Al Jamal A. Effect of rosemary (Rosmarinus officinalis) on lipid profiles and blood glucose in human diabetic patients (type-2). African J. Biochem. Res. 2014;8(8):147-50. DOI

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

Rosemary Also Interacts With Other Medications

Rosemary has 211 moderate, 160 minor known drug interactions in our database — the Metformin one above is one of them. If you take anything else, check it against the full list below.

Moderate 211 Minor 160 No known interaction 2,459 (incl. Metformin)
Taking anything else?

Check Another of Your Medications Against Rosemary

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

From our Q&A

Questions About Rosemary 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 Rosemary 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 Rosemary 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 Rosemary as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1,786 real supplement products containing Rosemary, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Rosemary. Your product may carry other ingredients that interact with Metformin too, on top of Rosemary — 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 Rosemary 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 Rosemary
Top 25%

#153 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 Rosemary

What is Rosemary?

Rosemary
  • Memory and concentration
  • Digestive upset
  • Hair growth
  • Anxiety and stress (aromatherapy)
  • Muscle and joint discomfort
  • Antioxidant support

Rosemary is a fragrant Mediterranean herb that is safe and flavorful in normal food amounts. Some early research suggests possible benefits for memory, mood, and hair growth, but the evidence is limited and far from conclusive. Concentrated supplements and the essential oil should be used carefully, and the essential oil should never be swallowed.

Read the full Rosemary 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 & Rosemary

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

0Major
211Moderate
160Minor
2,458No known interaction
211 Moderate 160 Minor 2,458 No interaction
Moderate

211 interactions

Showing 60 of 211 moderate interactions — see all 211 on the Rosemary page.

Minor

160 interactions

Showing 60 of 160 minor interactions — see all 160 on the Rosemary page.

No interaction 2,458 drugs checked — show the list

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

Showing the 60 most looked-up of 2,458 medications checked with no known interaction — see the full Rosemary list.

See the full Rosemary 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
Rosemary 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 Rosemary and Metformin Together: Common Questions

Can you take Rosemary with 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 Rosemary and 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 Metformin and Rosemary?

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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.