Thiamine + Metformin

Thiamine has 3 minor known drug interactions in our database — Metformin isn’t one of them. If you take anything else, check it against the full list below.

We haven’t checked that one against Thiamine yet — ask our pharmacists directly.

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

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

These two do not interact. The relationship runs the other way: the licensed record lists Metformin as associated with lower Thiamine levels — rated “Insufficient Evidence”.

See every medication linked to lower Thiamine levels · See the full Metformin nutrient report

Disclaimer: This checker finds which nutrients might be depleted by prescription or over-the-counter medications. Each nutrient depletion issue is rated based on clinical significance. Use your own professional judgment prior to making clinical decisions.© 2026 Therapeutic Research Center

These two come up together because they touch the same health topic — not because they do the same job. Metformin is a prescription medicine with approved uses on its FDA label. Thiamine is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Metformin is prescribed for: 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.

Thiamine has been studied for:

• Kidney failure studied, not established Thiamine has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

  Thiamine for kidney failure

  Oral thiamine has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

• Diabetes studied, not established Thiamine has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

  Thiamine for diabetes

  It is unclear if oral thiamine is beneficial for type 2 diabetes or gestational diabetes.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Metformin on your own; if you are taking Thiamine for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Thiamine 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:

• I Accidentally Chewed My Metformin. Is That Okay? Answered by Dr. Brian Staiger, PharmD · July 2023 ›
• Accidentally Took An Extra Dose Of Metformin Answered by Dr. Brian Staiger, PharmD · March 2023 ›
• Does Cinnamon Interact With Metformin? Answered by Dr. Brian Staiger, PharmD · March 2023 ›

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

This page covers Thiamine 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.

Open the Metformin interaction page ›

We hold 3 real supplement products containing Thiamine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Thiamine. Even though Thiamine 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:

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.

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.

Natural Medicines records Metformin as a medicine that can lower these. This is not an interaction with Thiamine — it is a separate effect of the medicine, and it is a reason some people are advised to supplement rather than to avoid one:

• COENZYME Q10›
• FOLIC ACID›
• THIAMINE›
• VITAMIN B12›

Read the full Metformin nutrient depletion report ›

Thiamine is itself a nutrient we track — see which medications may deplete THIAMINE.

Depletion records come from the licensed Natural Medicines database. Do not start a supplement on the strength of this page — ask your pharmacist or doctor whether it applies to you.