Drug & supplement interaction

Goji + Metformin, Sitagliptin

Metformin, Sitagliptin brand names: Janumet, Janumet XR.

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

Goji has a minor interaction with Metformin, Sitagliptin. Theoretically, concomitant use of goji fruit polysaccharides or goji root bark with antidiabetes drugs might have additive effects.

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

Goji and Metformin, Sitagliptin

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

Minor

ANTIDIABETES DRUGS

Why this applies to Metformin, Sitagliptin

Metformin, Sitagliptin falls under ANTIDIABETES DRUGS — the group Goji interacts with.

Theoretically, concomitant use of goji fruit polysaccharides or goji root bark with antidiabetes drugs might have additive effects.
Animal and in vitro research show that goji root bark and fruit polysaccharides might have hypoglycemic effects. However, clinical research has only shown that taking goji fruit polysaccharides with or without antidiabetes drugs modestly reduces postprandial glucose when compared with control, with no reports of hypoglycemia.
Severity Minor 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

Janumet combines two diabetes medicines (metformin and sitagliptin) that work to bring your blood sugar down. Here is the simple version: goji berries may also nudge your blood sugar a little lower on their own. So when you pair concentrated goji supplements with Janumet, the two could add up, and in theory your sugar might dip more than expected.

The good news is this is a minor, mostly theoretical concern. Human studies showed only a modest drop in after-meal blood sugar with goji, and no real cases of low blood sugar (shakiness, sweating, dizziness). Eating goji berries as food is very unlikely to matter. If you use a strong goji supplement, just keep an eye on your readings and check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Cai H, Liu F, Zuo P, Huang G, Song Z, Wang T, et al. Practical application of antidiabetic efficacy of Lycium barbarum polysaccharide in patients with type 2 diabetes. Med Chem. 2015;11(4):383-90.

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

Goji Also Interacts With Other Medications

Goji has 2 major, 930 moderate, 67 minor known drug interactions in our database — the Metformin, Sitagliptin one above is one of them. If you take anything else, check it against the full list below.

Major 2 Moderate 930 Minor 67 No known interaction 1,831 (incl. Metformin, Sitagliptin)
Taking anything else?

Check Another of Your Medications Against Goji

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

Everything else you take

See Every Supplement That Interacts With Metformin, Sitagliptin

This page covers Goji only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metformin, Sitagliptin 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, Sitagliptin page

“Many people prescribed metformin with sitagliptin (Janumet, Janumet XR) for type 2 diabetes also try herbs sold as blood sugar support, fenugreek among the most popular, and that habit is exactly where the risk on this page concentrates. Of 257 documented supplement interactions, 239 can push glucose in the same direction the medicatio…”

Reviewed by 2 · Jul 18, 2026

Open the Metformin, Sitagliptin interaction page

One more smart check

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

We hold 1,738 real supplement products containing Goji, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Goji. Your product may carry other ingredients that interact with Metformin, Sitagliptin too, on top of Goji — 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 Goji and Metformin, Sitagliptin 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 Goji
Top 10%

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

29 days ago today
Medication Metformin, Sitagliptin
Top half

#925 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 Goji

What is Goji?

Goji
  • General antioxidant support
  • Eye health
  • Immune support
  • Anti-aging and well-being
  • Blood sugar support

Goji berries are a nutritious fruit rich in antioxidants, vitamins, and plant polysaccharides, and they are safe for most people as a food. While they are popular for eye health, immune support, and general wellness, strong human evidence for most health claims is limited. Talk with your pharmacist or doctor before using concentrated goji supplements, especially if you take medications or are pregnant.

Read the full Goji monograph & all interactions
Keep checking

Other Drugs & Goji

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

2Major
930Moderate
67Minor
1,830No known interaction
2 Major 930 Moderate 67 Minor 1,830 No interaction
Major

2 interactions

Moderate

930 interactions

Showing 60 of 930 moderate interactions — see all 930 on the Goji page.

Minor

67 interactions

Showing 60 of 67 minor interactions — see all 67 on the Goji page.

No interaction 1,830 drugs checked — show the list

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

Showing the 60 most looked-up of 1,830 medications checked with no known interaction — see the full Goji list.

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

Can you take Goji with Metformin, Sitagliptin?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Goji and Metformin, Sitagliptin interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Metformin, Sitagliptin and Goji?

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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.