Inclusion Criteria:  HIV-1 seropositive status prior to or after screening. Chest radiograph compatible with pulmonary TB Positive sputum pert TB/Rifampicin (RIF) with one Ct<25 or subsequent culture confirmation RIF susceptibility diagnosed by GeneXpert MTB/RIF Residence within study catchment area If female of childbearing potential, willing to use contraception for the duration of study participation Able and willing to provide informed consent  Exclusion Criteria:  Any condition for which participation in the trial, as judged by the investigator, could compromise the well-being of the participant or prevent, limit or confound protocol-specified assessments. Is critically ill, and in the judgment of the investigator has a diagnosis likely to result in death during the trial or the follow-up period. TB meningitis or other forms of severe TB with high risk of a poor outcome as judged by the investigator. Pregnant or breastfeeding. Resistance to any first-line ATT drug demonstrated by susceptibility testing. More than 7 days ATT for the current episode of TB, prior to enrollment. Taking an ART regimen that contains Dolutegravir (DTG). Taking any fluoroquinolone antibiotic. Minimally advanced pulmonary TB on chest x-ray (NTRDA criteria). History of diabetes mellitus or fasting blood glucose ≥7.0 mmol/L on screening evaluation. History of congestive heart failure, chronic liver disease, autoimmune disease or malignancy. Consumption of >28 units (men) OR >21 units (women) of alcohol/week Use of metformin within 1 year prior to enrollment. History of sensitivity to metformin. Acute or chronic metabolic acidosis based on reported medical history or laboratory tests performed on screening evaluation. Body mass index (BMI) <17.0 kg/m2 on screening evaluation. Peripheral blood Cluster Differentiation 4 (CD4) T cell count <200 cells/mm3 on screening evaluation. Hemoglobin <10 g/dL on screening evaluation. Platelet count <50,000/mm3 on screening evaluation. Absolute neutrophil count <750 cells/mm3 on screening evaluation. Estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 calculated by the chronic kidney disease epidemiology (CKD-EPI) equation. Serum bicarbonate <20 mmol/L on screening evaluation. Asparate aminotransferase (AST or ALT) ≥3 times the upper limit of normal (ULN) on screening evaluation. Anti-hepatitis B surface antigen or hepatitis C virus seropositive. Imprisonment at the time of or after enrollment in the METHOD trial. Diagnosis of active COVID-19 at time of screening or high suspicion of active Coronavirus disease of 2019 (COVID-19) disease during screening