Clinical Trials

Inclusion Criteria:

We will recruit MCHS patients aged 30−75 years with prediabetes. Prediabetes will be defined as hemoglobin A1c 6.0%–6.4% in the 6 months prior to study enrollment. In addition to these criteria, patients must meet at least one of the following criteria:

• Body-mass index ≥25 kg/m², measured in the 12 months prior to study enrollment.

• Personal history of gestational diabetes mellitus (GDM).

Exclusion Criteria:

• HbA1c ≥6.5% in the 5 years prior to study enrollment.

• ALT >2.5× upper limit of normal in the 12 months prior to study enrollment. 

• Personal history of liver cirrhosis or malignancy.

• Estimated glomerular filtration rate of <60 mL/min/1.73m² in the 12 months prior to study enrollment. 

• History of bariatric surgery or planned bariatric surgery in the 3 months following study enrollment. 

• Long-term use of systemic glucocorticoids (i.e. steroids). Long-term use is defined as daily use for >90 days in the 12 months prior to study enrollment. Topical use is permitted.

• Current or planned use of glucose lowering medication, including GLP-1 agonists for weight loss, in the 3 months following study enrollment (e.g., metformin).

• Current (inclusive of the 6 months prior to randomization) or planned major lifestyle changes, such as diet, or exercise that could lower HbA1c results.

• Current or recent (i.e., in the 3 months prior to enrollment) use of GTC supplement or berberine.

• Pregnant, lactation phase, or planned pregnancy in the 3 months following study enrollment. 

• Allergy or intolerance to GTC supplement or berberine. 

• Ongoing anticoagulant use (e.g., warfarin). 

• Personal history of seizure disorder.

• Active cancer in the 5 years prior to study enrollment (with the exceptions of basal cell or squamous cell skin cancers).

• Patients empaneled with a virtual primary care provider via Primary Care on Demand (those that see Primary Care on Demand for episodes of acute care are eligible). 

• Current or past peanut or legume allergy.

• Current participation in another interventional clinical trial.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 8/22/2025. Questions regarding updates should be directed to the study team contact.