Drug & supplement interaction

European Barberry + Pioglitazone

Pioglitazone brand name: Actos.

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

Pioglitazone falls into 2 drug categories that European Barberry can interact with; the most serious is rated moderate. Theoretically, European barberry might increase the levels and clinical effects of CYP3A4 substrates.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

European Barberry and Pioglitazone

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

European Barberry interacts with whole categories of medication. Pioglitazone falls into 2 of those categories, so it can interact with European Barberry in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

1 of 2

Why this applies to Pioglitazone

Pioglitazone falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group European Barberry interacts with.

Theoretically, European barberry might increase the levels and clinical effects of CYP3A4 substrates.
There is very preliminary evidence suggesting that berberine, a constituent of European barberry, might inhibit the CYP3A4 enzyme. Theoretically, European barberry might have a similar effect.
Severity Moderate Likelihood Possible Evidence D

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 with pioglitazone (Actos) and European barberry. Your liver uses an enzyme called CYP3A4 to help break pioglitazone down. Berberine, the main active compound in barberry, may slow that enzyme a little. If it does, pioglitazone could clear out of your body more slowly and build up, which might nudge its effects and side effects upward, things like swelling in the legs, weight gain, or low blood sugar if you're on other diabetes meds.

I want to be honest about the strength here: this is theoretical, based on how berberine behaves in lab studies, not real patient cases. Food amounts of barberry are unlikely to matter, but concentrated supplements are a bigger unknown. Since barberry can also lower blood sugar on its own, check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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
Moderate

ANTIDIABETES DRUGS

2 of 2

Pioglitazone also falls under ANTIDIABETES DRUGS.

Theoretically, taking European barberry with antidiabetes drugs might increase the risk of hypoglycemia.
Preliminary clinical evidence suggests that European barberry juice reduces fasting glucose levels in patients with type 2 diabetes who are also taking antidiabetes drugs. Additionally, some animal studies show that berberine, a constituent of European barberry, has antiglycemic potential. Monitor blood glucose levels closely.
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 simple version: both pioglitazone (Actos) and European barberry can lower your blood sugar. Pioglitazone works by making your body more sensitive to insulin, and barberry (through its main compound, berberine) seems to nudge blood sugar down too. Stack the two and the effect can add up, so your sugar may drop lower than you expect.

The evidence here is fairly early, mostly small studies and animal data, so this isn't a guaranteed problem. Still, it's worth watching for signs of low blood sugar like shakiness, sweating, dizziness, or feeling foggy. If you'd like to try barberry, check in with your pharmacist or doctor first and keep an eye on your glucose readings so they can adjust things safely.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Singh, J. and Kakkar, P. Antihyperglycemic and antioxidant effect of Berberis aristata root extract and its role in regulating carbohydrate metabolism in diabetic rats. J Ethnopharmacol. 5-4-2009;123(1):22-26. PubMed
  2. Gao, C. R., Zhang, J. Q., and Huang, Q. L. [Experimental study on berberin raised insulin sensitivity in insulin resistance rat models]. Zhongguo Zhong.Xi.Yi.Jie.He.Za Zhi. 1997;17(3):162-164. DOI
  3. Lazavi F, Mirmiran P, Sohrab G, Nikpayam O, Angoorani P, Hedayati M. The barberry juice effects on metabolic factors and oxidative stress in patients with type 2 diabetes: A randomized clinical trial. Complement Ther Clin Pract. 2018;31:170-174. 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

European Barberry Also Interacts With Other Medications

European Barberry has 1,209 moderate known drug interactions in our database — the Pioglitazone one above is among them. If you take anything else, check it against the full list below.

Moderate 1,209 No known interaction 1,621 (incl. Pioglitazone)
Taking anything else?

Check Another of Your Medications Against European Barberry

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

Everything else you take

See Every Supplement That Interacts With Pioglitazone

This page covers European Barberry only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Pioglitazone page lists 356 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 6 major · 309 moderate · 41 minor.

From our pharmacist’s overview on the Pioglitazone page

“Most of what appears on this pioglitazone (Actos) list shares one trait: the ingredients lower blood sugar on their own, which sounds helpful until you remember pioglitazone already does that job for people with type 2 diabetes. Stacked together, they can push glucose too low, and I would read this list with genuine care.”

Reviewed by 2 · Jul 18, 2026

Open the Pioglitazone interaction page

One more smart check

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

We hold 2 real supplement products containing European Barberry, each one broken down to its full ingredient list — and combination products often carry several ingredients besides European Barberry. Your product may carry other ingredients that interact with Pioglitazone too, on top of European Barberry — 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 European Barberry and Pioglitazone 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 European Barberry
Top half

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

29 days ago today
Medication Pioglitazone
Top half

#1,250 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 European Barberry

What is European Barberry?

European Barberry
  • Digestive upset
  • Antimicrobial support
  • Blood sugar support
  • Cholesterol and metabolic support
  • Skin conditions

European barberry is a shrub whose root, bark, and berries contain berberine, a bitter plant alkaloid that has been studied mostly in isolated form. Some early research on berberine is promising for blood sugar and cholesterol, but high-quality evidence for the whole barberry herb is limited. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full European Barberry monograph & all interactions
Medication

About Pioglitazone

What Is Pioglitazone Used For?

Brand name: Actos

Pioglitazone tablets — sold as Actos and under the generic names Pioglitazone and Pioglitazone Hydrochloride — are used to improve blood sugar (glucose) control in adults with type 2 diabetes. They are taken along with diet and exercise, either alone or combined with other diabetes medicines such as a sulfonylurea, metformin, or insulin.

Pioglitazone is not for type 1 diabetes or diabetic ketoacidosis (a serious complication where the blood becomes too acidic). It only works when the body is still producing some of its own insulin.

See full Pioglitazone drug information
Keep checking

Other Drugs & European Barberry

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

0Major
1,209Moderate
0Minor
1,620No known interaction
1,209 Moderate 1,620 No interaction
Moderate

1,209 interactions

Showing 60 of 1,209 moderate interactions — see all 1,209 on the European Barberry page.

No interaction 1,620 drugs checked — show the list

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

Showing the 60 most looked-up of 1,620 medications checked with no known interaction — see the full European Barberry list.

See the full European Barberry interactions page
See every supplement checked against Pioglitazone, 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
European Barberry monograph › Uses, safety, and every drug interaction in one place Pioglitazone supplement interactions › Every supplement checked against Pioglitazone, ranked by severity Pioglitazone 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 European Barberry and Pioglitazone Together: Common Questions

Can you take European Barberry with Pioglitazone?
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.
Why are there 2 interactions listed for European Barberry and Pioglitazone?
Pioglitazone belongs to more than one drug category, and European Barberry interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the European Barberry and Pioglitazone 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 Pioglitazone and European Barberry?

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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.