Drug & supplement interaction

Ash + Metformin, Sitagliptin

Metformin, Sitagliptin brand names: Janumet, Janumet XR.

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

Ash has a moderate interaction with Metformin, Sitagliptin. Theoretically, concomitant use with antidiabetes drugs might affect glucose control and increase the risk of hypoglycemia.

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

Ash and Metformin, Sitagliptin

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

Moderate

ANTIDIABETES DRUGS

Why this applies to Metformin, Sitagliptin

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

Theoretically, concomitant use with antidiabetes drugs might affect glucose control and increase the risk of hypoglycemia. Dose adjustments to diabetes medications might be necessary. Animal research shows that ash seed/fruit extract reduces fasting levels of glucose. Although clinical research in patients without diabetes shows that ash seed/fruit extract does not significantly affect blood glucose levels, insulin levels, or homeostatic model of insulin resistance (HOMA-IR), it may lower the incremental glucose area under the curve and decrease 2-hour blood glucose following an oral glucose tolerance test. Ash seed/fruit extract has not been evaluated in patients with diabetes. Until more is known, use cautiously in patients taking antidiabetes drugs.
Some antidiabetes drugs include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, metformin (Glucophage), pioglitazone (Actos), rosiglitazone (Avandia), and others.
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

Janumet combines two diabetes medicines, metformin and sitagliptin, that both work to bring your blood sugar down. Ash seed extract has shown a mild blood-sugar-lowering effect in lab and animal studies, and in some human tests it slightly nudged glucose lower after a meal. So the concern here is simple addition: if ash gently lowers your sugar on top of what Janumet is already doing, the two together could push your levels too low.

Keep in mind this is theoretical and based on weak evidence, with ash never studied in people with diabetes, so I wouldn't lose sleep over it. Still, watch for signs of low blood sugar like shakiness, sweating, dizziness, or confusion. Check with your pharmacist or doctor before adding ash.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Zulet MA, Navas-Carretero S, Lara y Sánchez D, et al. A Fraxinus excelsior L. seeds/fruits extract benefits glucose homeostasis and adiposity related markers in elderly overweight/obese subjects: a longitudinal, randomized, crossover, double-blind,
  2. Montó F, Arce C, Noguera MA, et al. Action of an extract from the seeds of Fraxinus excelsior L. on metabolic disorders in hypertensive and obese animal models. Food Funct. 2014;5(4):786-96. PubMed
  3. Visen P, Saraswat B, Visen A, et al. Acute effects of Fraxinus excelsior L. seed extract on postprandial glycemia and insulin secretion on healthy volunteers. J Ethnopharmacol. 2009;126(2):226-32. 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

Ash Also Interacts With Other Medications

Ash has 257 moderate 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.

Moderate 257 No known interaction 2,573 (incl. Metformin, Sitagliptin)
Taking anything else?

Check Another of Your Medications Against Ash

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

Everything else you take

See Every Supplement That Interacts With Metformin, Sitagliptin

This page covers Ash 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 Ash as Part of a Dietary Supplement Product? Check It for Interactions

We hold 8 real supplement products containing Ash, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ash. Your product may carry other ingredients that interact with Metformin, Sitagliptin too, on top of Ash — 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 Ash 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 Ash
Steady interest

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

29 days ago today
Medication Metformin, Sitagliptin
Steady interest

#1,508 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 Ash

What is Ash?

Ash
  • Joint pain and arthritis
  • Fever
  • Constipation
  • Fluid retention (diuretic)
  • Bladder and urinary complaints
  • Weight management and blood sugar

Ash (Fraxinus excelsior and related species) is a tree whose leaves, bark, and seeds have a long history in folk medicine for arthritis, fever, and fluid retention. Solid human evidence is limited for nearly all of these uses, so it should not replace proven treatments. Talk with your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or taking other medicines.

Read the full Ash monograph & all interactions
Keep checking

Other Drugs & Ash

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

0Major
257Moderate
0Minor
2,572No known interaction
257 Moderate 2,572 No interaction
Moderate

257 interactions

Showing 60 of 257 moderate interactions — see all 257 on the Ash page.

No interaction 2,572 drugs checked — show the list

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

Showing the 60 most looked-up of 2,572 medications checked with no known interaction — see the full Ash list.

See the full Ash 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
Ash 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 Ash and Metformin, Sitagliptin Together: Common Questions

Can you take Ash with Metformin, Sitagliptin?
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 Ash and Metformin, Sitagliptin 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, Sitagliptin and Ash?

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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.