Clinical Research Directory

Inclusion Criteria: * BMI 25.0-50.0 kg/m² * Prediabetes defined as fasting plasma glucose of ≥100 mg/dL, or HbA1C ≥5.7, or HOMA-IR ≥2.5. Exclusion Criteria: * Women who are still having menses * Persons who take niacin, nicotinamide, or other vitamin B3-related supplementation and are not willing to discontinue supplementation for 3 weeks before medical screening and during the entire study period * Persons who consume moderate-large amounts of caffeine daily (\>2 cups of coffee or 8 oz caffeinated drinks per day) or consume less amounts of caffeine but believe withdrawal symptoms (e.g. headache) are likely if caffeine is stopped * Unstable weight (\>3% change during the last 2 months before entering the study)