Drug & supplement interaction

Safflower + Metformin, Rosiglitazone

Metformin, Rosiglitazone brand name: Avandamet.

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

Safflower has a moderate interaction with Metformin, Rosiglitazone. Theoretically, safflower oil might alter the effects of antidiabetes drugs.

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

Safflower and Metformin, Rosiglitazone

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

Moderate

ANTIDIABETES DRUGS

Why this applies to Metformin, Rosiglitazone

Metformin, Rosiglitazone falls under ANTIDIABETES DRUGS — the group Safflower interacts with.

Theoretically, safflower oil might alter the effects of antidiabetes drugs.
Some clinical research shows that taking safflower oil 10 grams daily for 3 weeks can increase fasting blood glucose in patients with type 2 diabetes. However, clinical research in patients with metabolic syndrome with or without impaired glucose tolerance shows that taking safflower oil 8 grams daily for 12 weeks reduces fasting glucose levels by around 8 mg/dL. Some clinical research also shows that taking safflower oil 8 grams daily for 16 weeks does not affect fasting glucose levels in patients with type 2 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

Avandamet pairs two diabetes medicines, metformin and rosiglitazone, to help lower your blood sugar. Neither one is a prodrug, so safflower doesn't change how your body activates them. Instead, the concern here is simpler: safflower oil itself may nudge your blood sugar one way or the other. The research is mixed and not very strong. One small study saw fasting glucose rise after a few weeks of safflower oil, while others showed a small drop or no change at all.

Because the effect is unpredictable, adding a concentrated safflower oil supplement could make your numbers a little harder to read, and could lead to lows (shakiness, sweating, dizziness) or highs (thirst, fatigue). Everyday cooking amounts are unlikely to matter. If you want to start a supplement, check with your pharmacist or doctor first and keep an eye on your readings.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Borkman M, Chisholm DJ, Furler SM, et al. Effects of fish oil supplementation on glucose and lipid metabolism in NIDDM. Diabetes 1989;38:1314-9.. PubMed
  2. Asp ML, Collene AL, Norris LE, Cole RM, Stout MB, Tang SY, Hsu JC, Belury MA. Time-dependent effects of safflower oil to improve glycemia, inflammation and blood lipids in obese, post-menopausal women with type 2 diabetes: a randomized, double-masked, cro
  3. Ruyvaran M, Zamani A, Mohamadian A, et al. Safflower (Carthamus tinctorius L.) oil could improve abdominal obesity, blood pressure, and insulin resistance in patients with metabolic syndrome: a randomized, double-blind, placebo-controlled clinical trial. 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

Safflower Also Interacts With Other Medications

Safflower has 207 moderate known drug interactions in our database — the Metformin, Rosiglitazone one above is one of them. If you take anything else, check it against the full list below.

Moderate 207 No known interaction 2,623 (incl. Metformin, Rosiglitazone)
Taking anything else?

Check Another of Your Medications Against Safflower

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

Everything else you take

See Every Supplement That Interacts With Metformin, Rosiglitazone

This page covers Safflower only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metformin, Rosiglitazone page lists 315 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Siberian Cocklebur (major), Wine (major) and Acai (moderate).

By severity: 4 major · 268 moderate · 43 minor.

From our pharmacist’s overview on the Metformin, Rosiglitazone page

“Avandamet pairs metformin with rosiglitazone to manage type 2 diabetes, and its supplement list calls for genuine care rather than a quick skim. Start with the four major-rated entries: alcohol and the herb Siberian cocklebur can each stress the liver, a serious concern with rosiglitazone on board, while activated charcoal can soak up…”

Reviewed by 2 · Jul 18, 2026

Open the Metformin, Rosiglitazone interaction page

One more smart check

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

We hold 276 real supplement products containing Safflower, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Safflower. Your product may carry other ingredients that interact with Metformin, Rosiglitazone too, on top of Safflower — 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 Safflower and Metformin, Rosiglitazone 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 Safflower
Top half

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

29 days ago today
Medication Metformin, Rosiglitazone
Steady interest

#1,697 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 Safflower

What is Safflower?

Safflower
  • Heart and cholesterol support
  • Skin moisturizing
  • Menstrual cramps
  • Mild constipation
  • Weight management (oil)

Safflower is a thistle-like plant used mainly for its seed oil (a common cooking oil) and its colorful flowers. Safflower oil is a reasonable source of unsaturated fats, but strong proof that supplements treat specific diseases is limited. The flower extracts have much weaker evidence and should be used with caution, especially during pregnancy.

Read the full Safflower monograph & all interactions
Keep checking

Other Drugs & Safflower

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

0Major
207Moderate
0Minor
2,622No known interaction
207 Moderate 2,622 No interaction
Moderate

207 interactions

Showing 60 of 207 moderate interactions — see all 207 on the Safflower page.

No interaction 2,622 drugs checked — show the list

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

Showing the 60 most looked-up of 2,622 medications checked with no known interaction — see the full Safflower list.

See the full Safflower interactions page
See every supplement checked against Metformin, Rosiglitazone, 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
Safflower monograph › Uses, safety, and every drug interaction in one place Metformin, Rosiglitazone supplement interactions › Every supplement checked against Metformin, Rosiglitazone, 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 Safflower and Metformin, Rosiglitazone Together: Common Questions

Can you take Safflower with Metformin, Rosiglitazone?
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 Safflower and Metformin, Rosiglitazone 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

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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.