Medication interaction hub

What Supplements Interact with Metformin?

Metformin brand names: Glucophage, Metformin. Every interaction below applies to the brands too.

258 Interactions 2 Major 217 Moderate 39 Minor
Curated & coded by · Clinical Pharmacist · Updated September 23, 2026

Drug–supplement interaction data sourced from Natural Medicines Pro, the licensed clinical database from TRC Healthcare / Therapeutic Research, with additional analysis by the HelloPharmacist Pharmacist Team. Our sources · Editorial policy

What is this page for?

One answer, for one medication: what supplements and herbal products interact with Metformin? Every vitamin, herb, and supplement ingredient we’ve checked against it is on this page, ranked by severity, each linking to the full report for that exact pair.

This page covers supplement interactions only — to check Metformin against your other medications, use the drug–drug interaction checker. Educational information from our licensed clinical databases, not medical advice. Our editorial policy

HelloPharmacist Bottom Line
Our Pharmacist Explains
What is this? The interaction data in the HelloPharmacist supplement database is licensed from Natural Medicines Pro by TRC Healthcare (Therapeutic Research). HelloPharmacist pharmacists often add our own analysis and context on top of that licensed data — such as this Bottom Line summary and the notes on individual interaction pages — and any such commentary is noted as ours.

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. It is one of only 2 major-rated interactions among the 258 supplements and herbs on file here, the other being activated charcoal, which can soak up drugs in the gut before they reach your bloodstream. This list warrants genuine care, not a quick skim.

The wider pattern is remarkably consistent. Another 217 entries rate moderate and 39 minor, and most act on blood sugar itself, either adding to metformin's glucose-lowering effect and raising the chance of a dangerous low, or occasionally pushing sugar upward and working against the drug. A smaller cluster of fibers and bulking agents, guar gum among them, can reduce how much metformin your body absorbs, so take those well apart from your dose.

— , Clinical Pharmacist · July 18, 2026

Major 2 Moderate 217 Minor 39 No known interaction 1,194

This box checks one ingredient at a time (like turmeric or magnesium). Taking a supplement product with a whole label of ingredients? Search the product instead — we check every ingredient on it ↓

Most Viewed Ingredient Interactions

Metformin: Top Interactions at a Glance

The Metformin supplement & herbal interactions people checked most in the last 24 hours, colored by severity. Tap any ingredient to open the full report for that pair.

Showing the 12 highest-ranked of 258 interacting ingredients — plus 1,194 more checked with no known interaction. See the complete ranked list.

Start here

The Most-Checked Metformin Combinations Today

The Metformin + supplement pages people viewed most in the last 24 hours (resets at midnight). Open any card for the full report.

Minor Likelihood Possible Vitamin B12 + Metformini

Metformin, a common medication used to manage type 2 diabetes, has been associated with lower vitamin B12 levels in some individuals.

Read the full interaction Moderate Likelihood Possible Oregano + Metformini

Theoretically, oregano might increase the risk for hypoglycemia when taken with antidiabetes drugs.

Read the full interaction Moderate Likelihood Possible Clove + Metformini

Theoretically, concomitant use of clove extracts with antidiabetes drugs might increase the risk of hypoglycemia.

Read the full interaction Moderate Likelihood Possible Berberine + Metformini

Theoretically, berberine may increase the risk of hypoglycemia when taken with antidiabetes drugs.

Read the full interaction Moderate Likelihood Possible Holy Basil + Metformini

Theoretically, holy basil might increase the risk of hypoglycemia when taken with antidiabetes drugs.

Read the full interaction Moderate Likelihood Possible Ashwagandha + Metformini

Theoretically, taking ashwagandha with antidiabetes drugs might increase the risk of hypoglycemia.

Read the full interaction
The complete list

Every Supplement Checked Against Metformin

All 1,452 ingredients in our database, ranked by severity — 258 with a Metformin interaction on file and 1,194 with none found. Filter by severity or search any ingredient; hover the for what each ingredient is.

Looking for an interaction with a specific supplement product? Search products instead ↓

Straight answers

Can You Take It With Metformin?

One-line answers, one card per combination — scroll through today’s 20 and tap any card for the full report. A different set rotates in daily until every combination has had its turn.

Can you take Vitamin B12 with Metformin?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Metformin, a common medication used to manage type 2 diabetes, has been associated with lower vitamin B12 levels in some individuals.

Full Vitamin B12 + Metformin answer

Can you take Oregano with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, oregano might increase the risk for hypoglycemia when taken with antidiabetes drugs.

Full Oregano + Metformin answer

Can you take Clove with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use of clove extracts with antidiabetes drugs might increase the risk of hypoglycemia.

Full Clove + Metformin answer

Can you take Berberine with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, berberine may increase the risk of hypoglycemia when taken with antidiabetes drugs.

Full Berberine + Metformin answer

Can you take Holy Basil with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, holy basil might increase the risk of hypoglycemia when taken with antidiabetes drugs.

Full Holy Basil + Metformin answer

Can you take Rhodiola with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking rhodiola with antidiabetes drugs might increase the risk of hypoglycemia.

Full Rhodiola + Metformin answer

Can you take Rosemary with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking rosemary with antidiabetes drugs might increase the risk of hypoglycemia.

Full Rosemary + Metformin answer

Can you take Rutin with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking rutin with antidiabetes drugs might increase the risk of hypoglycemia.

Full Rutin + Metformin answer

Can you take Safflower with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, safflower oil might alter the effects of antidiabetes drugs.

Full Safflower + Metformin answer

Can you take Saffron with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use of saffron with antidiabetes drugs might increase the risk of hypoglycemia.

Full Saffron + Metformin answer

Can you take Sage with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking sage with antidiabetes drugs might increase the risk of hypoglycemia.

Full Sage + Metformin answer

Can you take Sesame with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Taking sesame oil with antidiabetes drugs might increase the risk of hypoglycemia.

Full Sesame + Metformin answer

Can you take Shilajit with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Taking shilajit with antidiabetes drugs might increase the risk of hypoglycemia.

Full Shilajit + Metformin answer

Can you take Slippery Elm with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, slippery elm may slow the absorption and reduce serum levels of oral drugs.

Full Slippery Elm + Metformin answer

Can you take Solomon's Seal with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use may enhance hypoglycemic drug effects and alter blood glucose control.

Full Solomon's Seal + Metformin answer

Can you take Soy with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Soy can lower blood glucose and have additive effects with antidiabetes drugs.

Full Soy + Metformin answer

Can you take Spinach with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. There are claims that spinach leaves have hypoglycemic effects.

Full Spinach + Metformin answer

Can you take Stereospermum with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Animal research suggests that stereospermum can have hypoglycemic effects.

Full Stereospermum + Metformin answer

Can you take Stinging Nettle with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, stinging nettle might have additive effects with antidiabetes drugs.

Full Stinging Nettle + Metformin answer

Can you take Sunflower Oil with Metformin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, sunflower oil might decrease the effectiveness of antidiabetes medications.

Full Sunflower Oil + Metformin answer
Read the list like a pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. Interaction 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.
  • Possible. 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
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each entry links to a full report with the clinical detail, likelihood, evidence level, and citations for that exact combination.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

How Does Our Interaction Checker Work?

Behind every verdict on this page is a category system. Our source database doesn’t document supplement interactions drug-by-drug — it documents them against groups of medications that behave the same way (for example, “drugs processed by the CYP3A4 liver enzyme” or “blood-thinning medications”).

So the check works in three steps: (1) Metformin is classified into the pharmacology categories it belongs to, (2) every supplement interaction documented against any of those categories is inherited by Metformin, and (3) each ingredient keeps its own severity, likelihood, and evidence grades from the underlying record. That’s why one supplement can carry several records for one drug — it may interact through more than one category.

Metformin sits in 5 interaction categories. Open any one to see what the group means:

Antidiabetes Drugs 239 ingredients

Blood-sugar-lowering medications. Supplements that also lower glucose can push blood sugar too low when combined.

239 of the supplement ingredients on this page reach Metformin through this category.

Metformin (Glucophage) 18 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

18 of the supplement ingredients on this page reach Metformin through this category.

Oral Drugs 17 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

17 of the supplement ingredients on this page reach Metformin through this category.

Metmorphin (Glucophage) 1 ingredient

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

1 of the supplement ingredient on this page reaches Metformin through this category.

Organic Cation Transporter 2 (Oct2) Substrates 1 ingredient

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

1 of the supplement ingredient on this page reaches Metformin through this category.

About Metformin

Metformin is a biguanide medication used to help control blood sugar levels in type 2 diabetes.

Generic name: Metformin  ·  Brand names: Glucophage, Metformin.

See the full Metformin drug information

Related: does Metformin deplete any nutrients?

Metformin has 8 reported nutrient associations in the research literature — see the Metformin nutrient depletion report.

Check a real product

Take a Supplement Product? Check the Whole Bottle Against Metformin

Most supplements are combination products — and the interaction may come from an ingredient you didn’t buy it for. Search any product below (or scan its label) and we’ll check every ingredient on it against Metformin.

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Pharmacist Counseling Corner

Metformin & Supplements: Common Questions

What supplements interact with Metformin?
More than you might expect — 258 in total, though they are far from equal: 2 are rated major, 217 moderate, and 39 minor. The ranked list on this page puts the ones that genuinely matter first, and every entry opens a full report on that exact pair. The highest-ranked right now: Siberian Cocklebur, Activated Charcoal, American Ginseng.
Which Metformin supplement interactions are the most serious?
The 2 major-rated combinations — led by Siberian Cocklebur and Activated Charcoal — deserve real caution: these are the ones generally best avoided, or used only with your prescriber watching. If you take any of them today, don't panic and don't stop anything abruptly — call your pharmacist first. Jump to the ranked list.
Can I take vitamins or supplements while on Metformin?
Usually yes — most people on Metformin can take most supplements. The catch is the exceptions, and they aren't always the exotic ones (St. John's Wort trips up more prescriptions than almost anything sold next to it). Look up each ingredient you actually take in the list above, and treat "no known interaction" as a green-ish light, not a guarantee. Try the label scanner or the interaction checker.
Do brands like Glucophage have the same supplement interactions as Metformin?
Yes — Glucophage, Metformin all contain Metformin, so everything on this page applies to them equally. Interactions belong to the active drug, never to the brand on the box; the same is true of generics.
Where do these interaction ratings come from?
Every rating comes from the Natural Medicines database — the same evidence-graded reference pharmacists and hospitals use — and each interaction carries three separate grades: severity (how bad it can be), likelihood (how well it's documented in studies and case reports), and an evidence level. Our pharmacists review the content; we never let an AI decide an interaction. See how to read the ratings and our editorial policy.
Does Metformin deplete any vitamins or nutrients?
It might — Metformin has 8 reported nutrient-depletion associations in the research literature, which is a different question from interactions: instead of a supplement changing the drug, the drug may lower a nutrient over time. See the Metformin nutrient depletion report for the specifics and what to discuss with your pharmacist.
What about Metformin and my other medications?
This page covers Metformin against supplements and herbal ingredients. Checking Metformin against your other prescription or OTC medications is a different tool — our drug interaction checker covers that side. Head to the drug–drug interaction checker, or read the full Metformin drug information.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

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Sourcing

Where This Data Comes From — and Why You Can Trust It

🧪 Licensed clinical database

Every interaction verdict on this page comes from Natural Medicines Pro (TRC Healthcare / Therapeutic Research) — the same evidence-graded reference used by pharmacists and hospitals. We license this data directly; we do not scrape it, and no AI invents an interaction.

🧑‍⚕️ Pharmacist review

This page is curated and coded by , Clinical Pharmacist, with additional analysis by the HelloPharmacist Pharmacist Team. Editorial commentary is ours; the licensed interaction records are shown as sourced.

🔄 Kept current

Our interaction database refreshes on a weekly cycle, and this page re-checks the live database every time it’s rebuilt — what you see reflects the database as of September 23, 2026.

🔍 Full transparency

How every dataset on this site is sourced, licensed, and updated is documented publicly: our data sources · editorial policy · how we use AI.

Educational information, not medical advice. An interaction being on file does not mean it will happen to you — and absence of one is not proof of safety. Never start or stop a medication or supplement without talking to your pharmacist or doctor.