Zinc pills tested as a simple way to lower blood sugar in prediabetes
NCT ID NCT05835037
First seen Jun 25, 2026 · Last updated Jul 10, 2026 · Updated 2 times
Summary
This study tests whether taking a daily 30 mg zinc supplement for one year can lower blood sugar and HbA1c levels in people with prediabetes. Two hundred Amish adults aged 18–80 with prediabetes will be randomly assigned to receive either zinc or a placebo pill. Researchers will compare changes in fasting glucose and HbA1c at 6 and 12 months.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- zinc gluconate (30 mg tablet daily)
- What this could lead to
- If it works, this could point toward a simple, low-cost supplement to help control blood sugar in people with prediabetes.
- What could go wrong
- This is a mid-stage trial with 200 participants, so results may not apply to everyone. Zinc supplements can cause stomach upset and may interact with other medications.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 4
Runs after approval, following long-term safety and how well the treatment works in everyday use.
- Participants
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About 200 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Feb 2024
- Expected to finish
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Jul 2028
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 80 years
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Amish men or women who are 18 to 80 years old * Prediabetes (HgbA1c = 5.7-6.4% or fasting glucose levels 100-125 mg/dL) Exclusion Criteria: * Pregnant * Currently breastfeeding * History of severe gastrointestinal disorders or upper gastrointestinal surgery * Has hemochromatosis, cancer, liver disease, kidney disease, cardiovascular disease, or other coexisting malignancy * Hemoglobin \< 12.5 g/dl (male) or \< 11 g/dl (female) * Severe hypertension (blood pressure \> 160/95 mm Hg) * Has a creatinine greater than 2.0 mg/dl, aspartate aminotransferase (AST) or alanine transaminase (ALT) greater than 2 times the upper limit of normal, hematocrit (Hct) less than 32%, or thyroid-stimulating hormone (TSH) less than 0.4 or greater than 5.5 milli-international units (mIU) per liter. * At the discretion of the study physician or PI, taking medications that affect the outcomes of the study including, but not limited to, corticosteroids, anti-psychotic agents, protease inhibitors, oral contraceptives, estrogens, niacin, and some classes of antidepressants, statins, and antihypertensive medications * Zinc hypersensitivity * Use of denture adhesive containing zinc * Taking other medications or zinc-containing supplements and is unwilling or cannot safely, in the opinion of the study physician, discontinue their use at least 2 weeks prior to protocol initiation * Any other condition that would, in the opinion of the investigator, place them at an unacceptable risk or render them unable to meet the requirements of the protocol.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
1 site. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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Amish Research Clinic
RECRUITINGLancaster, Pennsylvania, 17602, United States
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