Drug & supplement interaction

Inositol Nicotinate + Metformin

Metformin brand names: Glucophage, Metformin.

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

Inositol Nicotinate has a moderate interaction with Metformin. Theoretically, inositol nicotinate might increase blood glucose levels and may diminish the effects of antidiabetes drugs.

Read the full interaction report
SeverityModerate
LikelihoodProbable
EvidenceB
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Inositol Nicotinate 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 Inositol Nicotinate interacts with.

Theoretically, inositol nicotinate might increase blood glucose levels and may diminish the effects of antidiabetes drugs.
Inositol nicotinate is metabolized to niacin in the body. Niacin can cause hyperglycemia, abnormal glucose tolerance, and glycosuria. Increased blood glucose monitoring may be necessary, particularly early in the course of treatment.
Severity Moderate Likelihood Probable Evidence B

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..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the practical concern with pairing this 'no-flush' niacin product with your metformin. Once swallowed, inositol nicotinate slowly releases niacin in your body, and niacin can nudge blood sugar upward. Since metformin's whole job is to bring your sugar down, the two can work against each other. In plain terms, your numbers might creep higher than usual, which could make your metformin feel like it isn't doing quite as much.

This is mostly theoretical and based on weaker studies, so don't panic. Metformin isn't activated by niacin, so it's not a hidden flip in direction, just a possible tug in the opposite direction. If you decide to use this, watch your home glucose readings more closely, especially in the first few weeks, and loop in your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Anon. Inositol hexaniacinate. Altern Med Rev 1998;3:222-3.
  2. Crouse JR III. New developments in the use of niacin for treatment of hyperlipidemia: new considerations in the use of an old drug. Coron Artery Dis 1996;7:321-6. PubMed
  3. Garg A, Grundy SM. Nicotinic acid as therapy for dyslipidemia in non-insulin-dependent diabetes mellitus. JAMA 1990;264:723-6. DOI
  4. McKenney J. New perspectives on the use of niacin in the treatment of lipid disorders. Arch Intern Med 2004;164:697-705. PubMed

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

Inositol Nicotinate Also Interacts With Other Medications

Inositol Nicotinate has 222 moderate 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 222 No known interaction 2,608 (incl. Metformin)
Taking anything else?

Check Another of Your Medications Against Inositol Nicotinate

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

From our Q&A

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

We hold 202 real supplement products containing Inositol Nicotinate, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Inositol Nicotinate. Your product may carry other ingredients that interact with Metformin too, on top of Inositol Nicotinate — 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 Inositol Nicotinate 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 Inositol Nicotinate
Top 25%

#269 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Metformin
Top 5%

#32 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 Inositol Nicotinate

What is Inositol Nicotinate?

Inositol Nicotinate
  • Cholesterol support
  • Improving circulation
  • Raynaud's phenomenon
  • Intermittent claudication (leg pain with walking)
  • A 'no-flush' niacin alternative

Inositol nicotinate is a 'no-flush' form of niacin marketed for cholesterol and circulation. Evidence that it works as well as regular niacin is weak and inconsistent, and it is not a proven replacement for prescription cholesterol treatment. Talk to your pharmacist or doctor before using it, especially if you have liver problems or take other medicines.

Read the full Inositol Nicotinate monograph & all interactions
Medication

About Metformin

What Is Metformin Used For?

Brand names: Glucophage, Metformin

Metformin — available as tablets, extended-release tablets, and an oral solution — is used to improve blood sugar (glucose) control in people with type 2 diabetes mellitus, always as part of a plan that includes diet and exercise.

Metformin hydrochloride tablets and the oral solution are approved for adults and children 10 years and older. Extended-release tablets (including Fortamet, Glumetza, and Metformin Hydrochloride Extended Release) are approved for adults only. Riomet (oral solution) is approved for adults and children 10 years and older.

See full Metformin drug information
Keep checking

Other Drugs & Inositol Nicotinate

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

0Major
222Moderate
0Minor
2,607No known interaction
222 Moderate 2,607 No interaction
Moderate

222 interactions

Showing 60 of 222 moderate interactions — see all 222 on the Inositol Nicotinate page.

No interaction 2,607 drugs checked — show the list

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

Showing the 60 most looked-up of 2,607 medications checked with no known interaction — see the full Inositol Nicotinate list.

See the full Inositol Nicotinate 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
Inositol Nicotinate 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 Inositol Nicotinate and Metformin Together: Common Questions

Can you take Inositol Nicotinate 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 Inositol Nicotinate 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 Inositol Nicotinate?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.