Patient description: The patient is a 24-year-old man who has had type 1 diabetes for 11 years. He presents to the emergency room with hyperglycemia and concern for possible diabetic ketoacidosis after not taking his insulin for 3 days. The patient reports that he is currently homeless and has lost his supply of insulin, syringes, glucometer, and glucose testing supplies. The patient states that at the time of his initial diagnosis with type 1 diabetes he was hospitalized with a glucose value >1000 mg/dL. At the time, he was experiencing polyuria, polydipsia, and polyphagia. He reports that he has been on insulin since the time of his diagnosis, and he has never been prescribed oral agents for diabetes management. Most recently, he has been using insulin glargine 55 units once daily, and insulin aspart sliding scale 3 times daily. The patient has had previous episodes of diabetic ketoacidosis, for which he was hospitalized. With this episode of hyperglycemia, he is not experiencing any nausea, vomiting, or abdominal discomfort, and he appears well. His lab studies showed: A1c: 11.3% Creatinine: 0.9 mg/dL with eGFR >60 mL/min Aspartate aminotransferase (AST): 17 U/L Alanine aminotransferase (ALT): 14 U/L Beta-hydroxybutyrate: 0.1 mmol/L Bicarbonate: 25 mEq/L Anion

Clinical trial eligibility criteria: eligible ages (years): 18.0-79.0,  HIV Infection Hepatitis C Male or female, 18 to 79 years old inclusive 2. Provision of informed consent 3. Documented history of chronic HCV RNA infection 4. Intending to start on any 8-12 week IFN-free HCV antiviral therapy 5. If HIV-infected and not on HIV antiretroviral therapy, a CD4 count at least > 200 6. Insulin resistance as determined by a HOMA-IR of > 2.0 at screening 7. Evidence of fibrosis on FibroScan® > 8.0 kPa, OR liver biopsy score > 2 (Batts-Ludwig System) [55] (within 2 years)  Pregnant, suspected to be pregnant, planning to become pregnant or breastfeeding 2. Chronic HBV infection 3. HbA1c > 8.0 4. Use of immune suppressing medications 5. Active malignancy 6. Current or any previous treatment with Metformin, other oral diabetes medications,insulin 7. Pre-existing diabetes (type 1, type 2 or gestational diabetes) 8. Clinical evidence of decompensated cirrhosis (ascites, esophageal varices, hepatic encephalopathy, hepatocellular carcinoma) 9. Presence of renal impairment or when renal function is not known, and also in patients with serum creatinine levels above upper limit of normal range. Renal disease or renal dysfunction (e.g., as suggested by serum creatinine levels >= 136 umol/L (males), >= 124 umol/L (females) or abnormal creatinine clearance (60 mL/min)) 10. History of congestive heart failure requiring pharmacologic therapy 11. Wilson's disease 12. Alpha-1 antitrypsin 13. Hemochromatosis 14. Biliary Cirrhosis 15. Alcohol consumption > 50 g / day on average (see Appendix B for conversion to volume) 16. Participation in other clinical investigations during the study 17. History of lactic acidosis, irrespective of precipitating factors Active illicit drug use and stable health illness will not be exclusionary assuming it is unlikely to compromise study adherence to protocol and study drug. In HIV-infected participants, HIV antiretroviral use and suppressed HIV viral load will not be required for participation. HCV antiviral therapy will not be withheld for any participant that is eligible and desires to start treatment. If HCV treatment is anticipated to be started during the 48-week period of assessment, then participants will not be enrolled