Medication interaction hub

What Supplements Interact with Metformin Hydrochloride?

Metformin Hydrochloride brand name: Riomet ER. Every interaction below applies to the brands too.

257 Interactions 2 Major 217 Moderate 38 Minor
Curated & coded by · Clinical Pharmacist · Updated September 26, 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 Hydrochloride? 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 Hydrochloride 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.

Anyone taking metformin hydrochloride (Riomet ER) should treat this list with genuine care, because two of its 257 entries are rated major. Siberian cocklebur has caused severe hypoglycemia in people and should not be combined with metformin at all, and activated charcoal can adsorb the drug in the gut so less reaches your blood. Beyond those two, the overwhelming pattern, 217 moderate entries plus 38 minor, is supplements that lower blood sugar on their own and can stack with metformin, dropping glucose further than intended.

A smaller cluster pushes the other way. A few entries raise blood sugar and blunt metformin's benefit, while bulky fibers such as guar gum slow its absorption, so space those well apart from your dose. Alcohol interferes too by impairing the liver's glucose output. Check your sugar more often when a supplement starts or stops, and learn the signs of a low: shakiness, sweating, sudden confusion.

— , Clinical Pharmacist · July 18, 2026

Major 2 Moderate 217 Minor 38 No known interaction 1,195

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 Hydrochloride: Top Interactions at a Glance

The Metformin Hydrochloride 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 257 interacting ingredients — plus 1,195 more checked with no known interaction. See the complete ranked list.

Start here

The Most-Checked Metformin Hydrochloride Combinations Today

The Metformin Hydrochloride + 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 + Metformin Hydrochloridei

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 Damiana + Metformin Hydrochloridei

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

Read the full interaction Moderate Likelihood Possible Ginkgo + Metformin Hydrochloridei

Theoretically, taking ginkgo with antidiabetes drugs might alter the response to antidiabetes drugs.

Read the full interaction Moderate Likelihood Possible Shilajit + Metformin Hydrochloridei

Taking shilajit with antidiabetes drugs might increase the risk of hypoglycemia.

Read the full interaction Minor Likelihood Possible Caffeine + Metformin Hydrochloridei

Theoretically, metformin might increase the levels and adverse effects of caffeine.

Read the full interaction Minor Likelihood Possible Guarana + Metformin Hydrochloridei

Theoretically, metformin might increase the levels and adverse effects of caffeine.

Read the full interaction
The complete list

Every Supplement Checked Against Metformin Hydrochloride

All 1,452 ingredients in our database, ranked by severity — 257 with a Metformin Hydrochloride interaction on file and 1,195 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 Hydrochloride?

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 Hydrochloride?

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 Hydrochloride answer

Can you take Damiana with Metformin Hydrochloride?

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

Full Damiana + Metformin Hydrochloride answer

Can you take Ginkgo with Metformin Hydrochloride?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking ginkgo with antidiabetes drugs might alter the response to antidiabetes drugs.

Full Ginkgo + Metformin Hydrochloride answer

Can you take Shilajit with Metformin Hydrochloride?

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 Hydrochloride answer

Can you take Caffeine with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, metformin might increase the levels and adverse effects of caffeine.

Full Caffeine + Metformin Hydrochloride answer

Can you take Atkins Diet with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, following the Atkins diet might have additive hypoglycemic effects.

Full Atkins Diet + Metformin Hydrochloride answer

Can you take Blueberry with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, blueberries or blueberry leaf extracts might increase the risk of hypoglycemia when taken with antidiabetes drugs.

Full Blueberry + Metformin Hydrochloride answer

Can you take Chanca Piedra with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, concomitant use with antidiabetes drugs might affect glucose control and increase the risk of hypoglycemia.

Full Chanca Piedra + Metformin Hydrochloride answer

Can you take Coconut with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, taking coconut with antidiabetes drugs might increase the risk of hypoglycemia.

Full Coconut + Metformin Hydrochloride answer

Can you take Coconut Water with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, taking coconut water with antidiabetes drugs might increase the risk of hypoglycemia.

Full Coconut Water + Metformin Hydrochloride answer

Can you take Coffee with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, concomitant use of coffee and antidiabetes drugs might interfere with blood glucose control.

Full Coffee + Metformin Hydrochloride answer

Can you take Glucosamine with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Despite initial concerns, it is unlikely that glucosamine will interfere with the effects of antidiabetes drugs.

Full Glucosamine + Metformin Hydrochloride answer

Can you take Green Coffee with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, taking green coffee and antidiabetes drugs might interfere with blood glucose control.

Full Green Coffee + Metformin Hydrochloride answer

Can you take Inulin with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, inulin might increase the risk of hypoglycemia with antidiabetes drugs.

Full Inulin + Metformin Hydrochloride answer

Can you take Kudzu with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, taking kudzu with antidiabetes drugs might increase the risk of hypoglycemia.

Full Kudzu + Metformin Hydrochloride answer

Can you take Mommy's Bliss Gripe Water with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Mommy's Bliss Gripe Water contains ginger.

Full Mommy's Bliss Gripe Water + Metformin Hydrochloride answer

Can you take Oolong Tea with Metformin Hydrochloride?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, taking oolong tea with antidiabetes drugs might interfere with blood glucose control.

Full Oolong Tea + Metformin Hydrochloride answer

Can you take Siberian Cocklebur with Metformin Hydrochloride?

Major Use real caution — this is a major-rated interaction, generally best avoided or used only under close supervision. Siberian cocklebur seedlings and seeds have caused severe hypoglycemia in humans.

Full Siberian Cocklebur + Metformin Hydrochloride answer

Can you take Activated Charcoal with Metformin Hydrochloride?

Major Use real caution — this is a major-rated interaction, generally best avoided or used only under close supervision. Activated charcoal reduces systemic exposure to many drugs, including those that undergo enterohepatic recirculation, regardless of the rout...

Full Activated Charcoal + Metformin Hydrochloride answer

Can you take American Ginseng with Metformin Hydrochloride?

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

Full American Ginseng + Metformin Hydrochloride 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 Hydrochloride is classified into the pharmacology categories it belongs to, (2) every supplement interaction documented against any of those categories is inherited by Metformin Hydrochloride, 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 Hydrochloride sits in 4 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 Hydrochloride 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 Hydrochloride 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 Hydrochloride 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 Hydrochloride through this category.

Related: does Metformin Hydrochloride deplete any nutrients?

Metformin Hydrochloride has 4 reported nutrient associations in the research literature — see the Metformin Hydrochloride nutrient depletion report.

Check a real product

Take a Supplement Product? Check the Whole Bottle Against Metformin Hydrochloride

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 Hydrochloride.

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Pharmacist Counseling Corner

Metformin Hydrochloride & Supplements: Common Questions

What supplements interact with Metformin Hydrochloride?
In our interaction database, 257 supplement and herbal ingredients have an interaction with Metformin Hydrochloride on file — 2 rated major, 217 moderate, and 38 minor. That number sounds scarier than it is: severity matters far more than the count, which is why the list on this page is ranked instead of alphabetical. Start at the top. The highest-ranked right now: Siberian Cocklebur, Activated Charcoal, American Ginseng.
Which Metformin Hydrochloride 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 Hydrochloride?
That depends entirely on which supplement. The honest answer for Metformin Hydrochloride is in the ranked list above — and if what you take is a combination product with a dozen ingredients, don't check them one by one: photograph the label with our scanner and we'll check the whole thing at once. Try the label scanner or the interaction checker.
Do brands like Riomet ER have the same supplement interactions as Metformin Hydrochloride?
Yes — Riomet ER all contain Metformin Hydrochloride, 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 Hydrochloride deplete any vitamins or nutrients?
It might — Metformin Hydrochloride has 4 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 Hydrochloride nutrient depletion report for the specifics and what to discuss with your pharmacist.
What about Metformin Hydrochloride and my other medications?
This page covers Metformin Hydrochloride against supplements and herbal ingredients. Checking Metformin Hydrochloride 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.

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

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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 26, 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.