Drug & supplement interaction

Goldthread + Metformin

Metformin brand names: Glucophage, Metformin.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Goldthread and Metformin in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Goldthread and Metformin

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Metformin and Goldthread in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Goldthread safety at a glance

Goldthread overall Use caution May be tolerated short-term by some adults, but human safety data are limited and quality varies between products.
Pregnancy Likely Unsafe When used orally. Berberine is thought to cross the placenta and may cause harm to the fetus. Kernicterus has developed in newborn infants exposed to berberine.... Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally. Berberine and other harmful constituents can be transferred to the infant through breast milk. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Metformin and Goldthread? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Metformin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Metformin is filed under 5 classifications — including organic cation transporter 2 (oct2) substrates, antidiabetes drugs, oral drugs. Goldthread has documented interactions with 2 drug classes — the most serious being cyclosporine (neoral, sandimmune) (moderate) and cytochrome p450 3a4 (cyp3a4) substrates (moderate) — and none of Metformin’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Goldthread Does Interact With Other Medications

Goldthread has 643 moderate known drug interactions in our database — Metformin isn’t one of them. If you take anything else, check it against the full list below.

Moderate 643 No known interaction 2,187 (incl. Metformin)
Taking anything else?

Check Another of Your Medications Against Goldthread

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

What to actually watch for

What Metformin’s Own FDA Label Lists

This is not an interaction — none of it involves Goldthread. These are the most notable effects listed in the ADVERSE REACTIONS section of Metformin’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both. 5 of them are worth acting on rather than waiting out — marked below.

  • Low blood sugar Worth acting on
  • High blood sugar Worth acting on
  • Chest pain Worth acting on
  • Shortness of breath Worth acting on
  • Liver problems Worth acting on
  • A change in taste
  • Chills
  • Flushing
  • Bloating or gas
  • Sweating

Showing the 10 most notable of 19 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Metformin. Read the label on DailyMed › Goldthread’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Goldthread side to compare — that is a limit of the record, not a statement that Goldthread has no side effects.

Special populations

Goldthread in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used orally. Berberine is thought to cross the placenta and may cause harm to the fetus. Kernicterus has developed in newborn infants exposed to berberine. Preliminary evidence suggests that maternal intake of goldthread during the first trimester increases the risk of congenital malformations of the central nervous system.

Lactation Likely Unsafe

When used orally. Berberine and other harmful constituents can be transferred to the infant through breast milk.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

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

We hold 25 real supplement products containing Goldthread, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Goldthread. Even though Goldthread itself has no known interaction with Metformin, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Goldthread 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 Goldthread
Top 25%

#295 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Goldthread reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Goldthread and Metformin records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Goldthread

What is Goldthread?

Goldthread
  • Digestive upset and diarrhea
  • Mouth sores and sore throat
  • Inflammation
  • Antimicrobial (fighting germs)
  • Blood sugar support
  • Skin and eye complaints

Goldthread is a traditional Chinese and East Asian herb whose root is rich in berberine, a compound being studied for blood sugar, cholesterol, and antimicrobial effects. Strong human evidence for goldthread itself is limited, and it should be avoided in pregnancy and breastfeeding. Talk with your pharmacist or doctor before using it, especially if you take other medicines.

Coptis chinensis · Ranunculaceae · Root and rhizome (the underground stem) · Dried root, powder, capsules, tinctures, teas, and topical preparations

An interaction check asks whether these two react with each other — it does not ask whether Goldthread is a good idea for someone in your situation. Here is what our Goldthread record says about it on its own.

Goldthread: dosing

There is no well-established standard dose for goldthread. Products differ widely in how they are made and how much active compound they contain, so it is hard to recommend a single safe amount.The best approach is to follow the directions on the product label and not exceed them.

From our Goldthread monograph — the full record covers uses, side effects and every documented interaction.

Read the full Goldthread 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 & Goldthread

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

0Major
643Moderate
0Minor
2,186No known interaction
643 Moderate 2,186 No interaction
Moderate

643 interactions

Showing 60 of 643 moderate interactions — see all 643 on the Goldthread page.

No interaction 2,186 drugs checked — show the list

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

Showing the 60 most looked-up of 2,186 medications checked with no known interaction — see the full Goldthread list.

See the full Goldthread interactions page
See every supplement checked against Metformin, ranked by severity
Evidence & sources

Goldthread References

The 3 references that drive our Goldthread monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Chan E. Displacement of bilirubin from albumin by berberine. Biol Neonate 1993;63:201-8. PubMed
  2. Wu X, Li Q, Xin H, Yu A, Zhong M. Effects of berberine on the blood concentration of cyclosporin A in renal transplanted recipients: clinical and pharmacokinetic study. Eur J Clin Pharmacol 2005;61:567-72. PubMed
  3. Chuang CH, Doyle P, Wang JD, et al. Herbal medicines used during the first trimester and major congenital malformations: an analysis of data from a pregnancy cohort study. Drug Saf 2006;29:537-48. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Goldthread and Metformin Together: Common Questions

Is it safe to take Goldthread with Metformin?
We do not list a known interaction between Goldthread and Metformin. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
How was the Goldthread and Metformin combination checked?
Interactions in our licensed database are recorded against drug classes. Metformin is filed under 5 classifications, and Goldthread has documented interactions with 2 drug classes — none of Metformin's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Goldthread interact with any other medications?
Yes. Goldthread has 643 documented drug interactions in our database — Metformin is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Metformin interact with any supplements?
Yes. Metformin has documented interactions with 258 supplements in our database — Goldthread is not one of them. The Metformin interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Goldthread monograph Uses, safety profile, and every drug interaction in one place Metformin drug information The full plain-English guide to this medication Metformin supplement interactions Every supplement checked against 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 References The 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Metformin and Goldthread?

Our pharmacists answer your medication & supplement questions — free.

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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.