Drug & supplement interaction

Annatto + Glipizide, Metformin

Glipizide, Metformin brand name: Metaglip.

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

Annatto has a moderate interaction with Glipizide, Metformin. Animal studies suggest that certain annatto extracts may have hypoglycemic or hyperglycemic effects.

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

Annatto and Glipizide, Metformin

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

Moderate

ANTIDIABETES DRUGS

Why this applies to Glipizide, Metformin

Glipizide, Metformin falls under ANTIDIABETES DRUGS — the group Annatto interacts with.

Animal studies suggest that certain annatto extracts may have hypoglycemic or hyperglycemic effects. Theoretically, taking annatto with antidiabetes drugs could reduce the therapeutic effects of these drugs or increase the risk for additive hypoglycemia. Monitor blood glucose levels closely.
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 honest picture: this combination is mostly a theoretical concern. The flag comes from animal studies where annatto extracts pushed blood sugar in either direction. We don't have solid human data, so I wouldn't lose sleep over the dash of annatto coloring your cheese or rice. Concentrated annatto supplements are a different story and worth a heads-up.

Why it matters with Metaglip (glipizide plus metformin): glipizide already nudges your body to release insulin, so if annatto adds its own sugar-lowering effect, you could stack them and see shakiness, sweating, dizziness, or low blood sugar. On the flip side, if annatto raised your sugar, your numbers might creep up. If you start a supplement, check your glucose more closely and loop in your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  2. Fernandes, A. C., Almeida, C. A., Albano, F., Laranja, G. A., Felzenszwalb, I., Lage, C. L., de Sa, C. C., Moura, A. S., and Kovary, K. Norbixin ingestion did not induce any detectable DNA breakage in liver and kidney but caused a considerable impairment
  3. Russell, K. R., Morrison, E. Y., and Ragoobirsingh, D. The effect of annatto on insulin binding properties in the dog. Phytother Res 2005;19(5):433-436. PubMed
  4. Morrison, E. Y., Thompson, H., Pascoe, K., West, M., and Fletcher, C. Extraction of an hyperglycaemic principle from the annatto (Bixa orellana), a medicinal plant in the West Indies. Trop.Geogr.Med 1991;43(1-2):184-188.
  5. Russell, K. R., Omoruyi, F. O., Pascoe, K. O., and Morrison, E. Y. Hypoglycaemic activity of Bixa orellana extract in the dog. Methods Find.Exp.Clin.Pharmacol. 2008;30(4):301-305.

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

Annatto Also Interacts With Other Medications

Annatto has 85 moderate known drug interactions in our database — the Glipizide, Metformin one above is one of them. If you take anything else, check it against the full list below.

Moderate 85 No known interaction 2,745 (incl. Glipizide, Metformin)
Taking anything else?

Check Another of Your Medications Against Annatto

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

Everything else you take

See Every Supplement That Interacts With Glipizide, Metformin

This page covers Annatto only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Glipizide, Metformin page lists 307 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), Adrafinil (moderate) and African Wild Potato (moderate).

By severity: 2 major · 257 moderate · 48 minor.

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

“Glipizide and metformin (Metaglip) already work hard to pull blood sugar down, which is exactly why this list of 307 ingredients deserves genuine vigilance rather than a shrug. Most of them, 239, can lower glucose on their own, and stacked on this pill the combined effect can tip into true hypoglycemia.”

Reviewed by 2 · Jul 18, 2026

Open the Glipizide, Metformin interaction page

One more smart check

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

We hold 304 real supplement products containing Annatto, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Annatto. Your product may carry other ingredients that interact with Glipizide, Metformin too, on top of Annatto — 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 Annatto and Glipizide, 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 Annatto
Steady interest

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

29 days ago today
Medication Glipizide, Metformin
Top half

#1,412 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 Annatto

What is Annatto?

Annatto
  • Natural food and cosmetic coloring
  • Source of antioxidants
  • Antimicrobial/anti-infective (traditional use)
  • Athletic performance and muscle soreness
  • Skin and bad-breath remedies (traditional use)

Annatto is a plant-based coloring made from the seeds of the achiote tree and is widely used as a safe food dye. While it has a long history in traditional medicine and contains antioxidant compounds, there is little high-quality human research supporting its use as a supplement. It can trigger allergic reactions in some people, so use caution and talk with your pharmacist or doctor.

Read the full Annatto monograph & all interactions
Keep checking

Other Drugs & Annatto

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

0Major
85Moderate
0Minor
2,744No known interaction
85 Moderate 2,744 No interaction
Moderate

85 interactions

Showing 60 of 85 moderate interactions — see all 85 on the Annatto page.

No interaction 2,744 drugs checked — show the list

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

Showing the 60 most looked-up of 2,744 medications checked with no known interaction — see the full Annatto list.

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

Can you take Annatto with Glipizide, 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 Annatto and Glipizide, 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 Glipizide, Metformin and Annatto?

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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.