Drug & supplement interaction

Capsicum + Metformin Hydrochloride

Metformin Hydrochloride brand name: Riomet ER.

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

Capsicum has a moderate interaction with Metformin Hydrochloride. Theoretically, taking capsicum with antidiabetes drugs might increase the risk of hypoglycemia.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Capsicum and Metformin Hydrochloride

Here is the interaction we found between these two, with the evidence behind it.

Moderate

ANTIDIABETES DRUGS

Why this applies to Metformin Hydrochloride

Metformin Hydrochloride falls under ANTIDIABETES DRUGS — the group Capsicum interacts with.

Theoretically, taking capsicum with antidiabetes drugs might increase the risk of hypoglycemia.
Preliminary clinical research shows that consuming capsicum 5 grams along with a glucose drink attenuates the rise in plasma glucose after 30 minutes by 21%, decreases the 2-hour postprandial area under the curve of plasma glucose by 11%, and increases the 2-hour postprandial area under the curve of plasma insulin by 58% in healthy individuals when compared with placebo. Other clinical research shows that taking capsicum 5 mg daily for 28 days significantly reduces postprandial blood glucose and insulin levels, but not fasting blood glucose and insulin levels, in patients with gestational diabetes.
Severity Moderate Likelihood Possible Evidence B

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.

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

Here's the gist: capsicum (chili pepper) may gently lower your blood sugar on its own, especially the rise you'd normally see after a meal. Since metformin is already working to keep your glucose down, stacking the two could push your numbers a little lower than expected. The good news is that metformin by itself rarely causes true low blood sugar, so the risk here is fairly modest.

Still, it's worth knowing what a low feels like: shakiness, sweating, dizziness, hunger, or feeling foggy. This is based on small, early studies, so it's more of a heads-up than a red alarm. Eating chili in your food is unlikely to be a problem; concentrated capsicum capsules are where I'd be more cautious. Check with your pharmacist or doctor before adding a supplement, and keep an eye on your readings.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chaiyata, P., Puttadechakum, S., and Komindr, S. Effect of chili pepper (Capsicum frutescens) ingestion on plasma glucose response and metabolic rate in Thai women. J.Med.Assoc.Thai. 2003;86(9):854-860.
  2. Chaiyasit, K., Khovidhunkit, W., and Wittayalertpanya, S. Pharmacokinetic and the effect of capsaicin in Capsicum frutescens on decreasing plasma glucose level. J Med.Assoc.Thai. 2009;92(1):108-113.
  3. Yuan LJ, Qin Y, Wang L, et al. Capsaicin-containing chili improved postprandial hyperglycemia, hyperinsulinemia, and fasting lipid disorders in women with gestational diabetes mellitus and lowered the incidence of large-for-gestational-age newborns. Clin 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

Capsicum Also Interacts With Other Medications

Capsicum has 214 moderate, 24 minor known drug interactions in our database — the Metformin Hydrochloride one above is one of them. If you take anything else, check it against the full list below.

Moderate 214 Minor 24 No known interaction 2,592 (incl. Metformin Hydrochloride)
Taking anything else?

Check Another of Your Medications Against Capsicum

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

Everything else you take

See Every Supplement That Interacts With Metformin Hydrochloride

This page covers Capsicum only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metformin Hydrochloride page lists 257 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 · 38 minor.

From our pharmacist’s overview on the Metformin Hydrochloride page

“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.”

Reviewed by 2 · Jul 18, 2026

Open the Metformin Hydrochloride interaction page

One more smart check

Taking Capsicum as Part of a Dietary Supplement Product? Check It for Interactions

We hold 4,130 real supplement products containing Capsicum, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Capsicum. Your product may carry other ingredients that interact with Metformin Hydrochloride too, on top of Capsicum — 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 Capsicum and Metformin Hydrochloride 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 Capsicum
Top 5%

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

29 days ago today
Medication Metformin Hydrochloride
Top 5%

#134 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 Capsicum

What is Capsicum?

  • Nerve pain (neuropathy)
  • Muscle and joint pain (arthritis)
  • Back pain
  • Digestive support
  • Cluster headache (intranasal)

Capsicum (chili pepper) contains capsaicin, which is best known and best studied as a topical treatment for certain types of pain. Topical capsaicin products are supported by reasonable evidence for some nerve and joint pain, but oral supplements are far less proven. Use it carefully, follow product directions, and talk to your pharmacist or doctor before starting.

Read the full Capsicum monograph & all interactions
Keep checking

Other Drugs & Capsicum

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

0Major
214Moderate
24Minor
2,591No known interaction
214 Moderate 24 Minor 2,591 No interaction
Moderate

214 interactions

Showing 60 of 214 moderate interactions — see all 214 on the Capsicum page.

Minor

24 interactions

No interaction 2,591 drugs checked — show the list

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

Showing the 60 most looked-up of 2,591 medications checked with no known interaction — see the full Capsicum list.

See the full Capsicum interactions page
See every supplement checked against Metformin Hydrochloride, 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
Capsicum monograph › Uses, safety, and every drug interaction in one place Metformin Hydrochloride supplement interactions › Every supplement checked against Metformin Hydrochloride, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Capsicum and Metformin Hydrochloride Together: Common Questions

Can you take Capsicum with Metformin Hydrochloride?
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 Capsicum and Metformin Hydrochloride 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 Hydrochloride and Capsicum?

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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.