- Individuals who are already taking metformin or other antidiabetic medications including insulin, have a diagnosis of diabetes, have a known allergy or FDA-labeled contraindication to taking metformin, eGFR below 30 mL/min per 1.73 m2 or other clinical diagnosis of advanced renal disease,, have acute or chronic metabolic acidosis (serum bicarbonate <22 mEq/L), have a history of significant alcohol use (>2 drinks/day on average), have a history of hepatic dysfunction (serum bilirubin 1.5X greater than the upper limit of normal), have a history of New York Heart Association (NYHA) Class III or IV heart failure, or are pregnant will be excluded from the trial.