Drug & supplement interaction

Lychee + Metformin, Sitagliptin

Metformin, Sitagliptin brand names: Janumet, Janumet XR.

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

Lychee has a moderate interaction with Metformin, Sitagliptin. Theoretically, lychee seed might increase the risk of hypoglycemia when used with antidiabetes drugs.

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

Lychee 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 Lychee interacts with.

Theoretically, lychee seed might increase the risk of hypoglycemia when used with antidiabetes drugs.
Animal research suggests that an aqueous extract of lychee seed reduces fasting and 2-hour postprandial blood glucose and improves impaired glucose tolerance in rats with type 2 diabetes. Additionally, retrospective research in children has found an association between lychee consumption and increased odds of acute hypoglycemic encephalopathy.
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 pairs two diabetes medicines, metformin and sitagliptin, that both work to lower your blood sugar. The concern here isn't about how your body breaks down these drugs. Instead, concentrated lychee seed extracts may have their own mild blood-sugar-lowering effect. Stacked on top of Janumet, that could theoretically push your sugar a little too low, leaving you shaky, sweaty, dizzy, or unusually tired.

I want to be honest about the evidence: this is theoretical, based mostly on animal studies and reports in undernourished children. Simply enjoying lychee fruit as a snack is very unlikely to cause trouble. If you're thinking about a lychee seed 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. Guo JW. Effects of Litchi seed on enhancing insulin sensitivity in type 2 diabetic-insulin resistant rats. Chinese J New Drugs 2003;12:526-9.
  2. Shrivastava A, Kumar A, Thomas JD, et al. Association of acute toxic encephalopathy with litchi consumption in an outbreak in Muzaffarpur, India, 2014: a case-control study. Lancet Glob Health. 2017;5(4):e458-e466.

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

Lychee Also Interacts With Other Medications

Lychee has 85 moderate, 121 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.

Moderate 85 Minor 121 No known interaction 2,624 (incl. Metformin, Sitagliptin)
Taking anything else?

Check Another of Your Medications Against Lychee

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

Everything else you take

See Every Supplement That Interacts With Metformin, Sitagliptin

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

We hold 98 real supplement products containing Lychee, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lychee. Your product may carry other ingredients that interact with Metformin, Sitagliptin too, on top of Lychee — 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 Lychee 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 Lychee
Top half

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

29 days ago today
Medication Metformin, Sitagliptin
Steady interest

#1,505 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 Lychee

What is Lychee?

  • General nutrition and antioxidant support
  • Digestive complaints (traditional use)
  • Cough and sore throat (traditional use)
  • Blood sugar support (preliminary)
  • Weight and metabolic support (preliminary)

Lychee is a sweet tropical fruit that is nutritious and a source of vitamin C and antioxidant plant compounds. While the fruit is a healthy food for most people, supplement-strength extracts have only limited research behind specific health claims, and eating large amounts of unripe lychee on an empty stomach has been linked to dangerous low blood sugar in undernourished children. Talk to your pharmacist or doctor before using lychee extracts for any health condition.

Read the full Lychee monograph & all interactions
Keep checking

Other Drugs & Lychee

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

0Major
85Moderate
121Minor
2,623No known interaction
85 Moderate 121 Minor 2,623 No interaction
Moderate

85 interactions

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

Minor

121 interactions

Showing 60 of 121 minor interactions — see all 121 on the Lychee page.

No interaction 2,623 drugs checked — show the list

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

Showing the 60 most looked-up of 2,623 medications checked with no known interaction — see the full Lychee list.

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

Can you take Lychee 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 Lychee 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 Lychee?

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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.