Interaction Between Inorganic Nitrate Supplementation and Metformin in Individuals With Prediabetes

Recruiting now · Not applicable · Has a placebo group

Conditions studied: Males, Females, Sedentary, Metformin, Prediabetes

In brief

This study is examining whether short-term supplementation with inorganic nitrate, in the form of beetroot juice, can enhance blood vessel health, insulin sensitivity, and exercise capacity in individuals with prediabetes. We will be comparing the responses in individuals who are taking metformin to those who are naive to metformin. The results from this study may help identify non-pharmacological interventions in prediabetes.

Key facts

Study ID: NCT07131384
Run by: University of Virginia
People needed: 24
Starts: 2026-01-01
Expected to finish: 2027-06-30
Last updated by the study team: 2026-06-03

Who can join

Age: 18 and older, up to 60. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

Individuals who can communicate meaningfully with the investigator and can provide written consent.
Confirmed prediabetic individuals (ages 18-60 years old) (2-hour glucose of 140-199 mg/dL following OGTT test or HbA1c between 5.7-6.4% tested on two occasions within 6 months).
Taking metformin (stable dose for at least a week) or naïve to metformin
Sedentary (<1 day/week of structured exercise)
Be able to perform exercise on a cycle ergometer without assistance
Stable medication regimen for the last 6 months
If female, have a normal menstrual cycle

You may not qualify if…

Estimated Glomerular filtration rate (GFR) ≤ 45
Body mass index ≥ 40 Kg/m2
HbA1c > 6.4%
Smokers within the last 5 years
Has experienced significant weight loss \~3 kg in the last three months or is taking any weight loss drugs
Current medical condition that prohibits exercising at high intensities
Currently on hormone replacement of any kind
History of myocardial infarction, cerebrovascular event, acute or unstable disease other than pre-diabetes or obesity
Currently taking any of the following medications (calcium channel blockers, statins, ACE or renin inhibitors, angiotensin receptor blockers, organic nitrates (e.g., nitroglycerine) or recent regular use of inorganic nitrates, alpha- or beta-blockers, diuretics, proton pump inhibitors, PDE-5 inhibitors (e.g.,: Cialis, Viagra), or xanthine oxidase inhibitors (e.g.,: Allopurinol))
Oral antibiotic use within the previous four weeks, including over-the-counter antibacterial mouthwash or a mouthwash containing chlorhexidine and unwilling to discontinue use
Oral cancer/severe oral disease
Uncontrolled hypertension (>140/90)
Had hysterectomy or oophorectomy
Fetuses, neonates, children, prisoners, cognitively impaired, non-English speaking participants

Where it is running

University of Virginia — Charlottesville, Virginia, United States (enrolling)

Full record on ClinicalTrials.gov

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