The overall purpose of this study is to identify how empagliflozin (a drug commonly used to treat type 2 diabetes) impacts skeletal muscle metabolic health among adults with prediabetes. Our aims are to: 1) Test the ability of empagliflozin to improve regulation of glucose metabolism (i.e., blood sugar) among overweight and obese individuals at risk for diabetes, and 2) Identify mechanisms to explain how empagliflozin may improve skeletal muscle glucose metabolism. We hypothesize empagliflozin will improve regulation of glucose metabolism due to changes in whole-body and skeletal muscle metabolism (e.g., increased rates of whole-body fat oxidation, evidence of impaired skeletal muscle mitochondrial respiratory function and increased energetic stress, lower accumulation of skeletal muscle lipids and improved skeletal muscle insulin signaling compared with placebo treatment).

The overall study design is a 13-week, double-blind, placebo-controlled intervention trial, testing the ability of empagliflozin to improve glucose metabolism among overweight and obese individuals at risk for diabetes (compared with a multivitamin-placebo). The study involves metabolic testing before and during the intervention to identify changes in outcomes as a function of the intervention and to ensure participant safety. The study involves 9 visits to the Samaritan Athletic Medicine Center on the campus of Oregon State University in Corvallis, Oregon. Full completion of the study is anticipated to take ~4 months. The project is being completed in collaboration with physicians at Samaritan Health Services.

Inclusion Criteria:

• BMI 26-45 kg/m2
• Weight stable (± 10 lbs in previous 3 months)
• Fasting blood glucose <126 mg/dL or HbA1c <6.5% (<48mmol/mol)

Exclusion Criteria:

• Regular moderate-vigorous exercise (≥30 min/session on ≥2 days per week)
• Pregnancy, planning to become pregnant or nursing
• Lidocaine allergy
• Current or recent smoking or nicotine use (≤ 1-year abstention)
• Medications including glucose lowering medications and supplements (SGLT2 inhibitors, GLP1 agonists, sulfonylurea, insulin, TZDs); mono-amine oxidase inhibitors; beta-blockers; diuretics
• Major metabolic or cardiovascular conditions (e.g., type 1 diabetes, Crohn's disease, untreated hypo- or hyperthyroid, cancer, coronary artery disease, tachycardia, prior bariatric surgery, peripheral vascular disease, liver diseases (e.g., cirrhosis)
• Diagnosed type 2 diabetes. In absence of diagnosis, two separate samples with test results of fasting blood glucose ≥126 mg/dL or HbA1c ≥6.5% (48 mmol/mol).
• Contraindications/precautions for empagliflozin (impaired renal function (EGR<60), history of: empagliflozin hypersensitivity, ketoacidosis, hypotension, recurring urinary tract or genital mycotic infections, amputation)

The current study is a pilot and feasibility project. IPD will not be made publicly available, save for publication and reporting requirements. Individual requests for data will be addressed by the Principal Investigator.

Pills will be prepared and dispensed by a pharmacy to blind participants and investigators.