Study aim: effect of meformin in any need to hospitalization, ARDS symptoms and mortality in patients with COVID-19 Design: The randomized clinical trial with a parallel group design in which 200 patients will be enrolled between 20 March 2020 till 18 April 2020 Settings and conduct: This study will be performed in outpatient clinic of corona of tabriz university of medical sciences,Tabriz, Iran. In this study 200 patients who are selected based on inclusion and exclusion criteria will be divided into two groups (100 in each group) by block randomization.Patients in control group will be prescribed standard regimen for COVID-19. Patients in Metformin group will be prescribed Metformin 500 mg BID for two weeks and standard regimen for COVID-19. The routine lab data, need for hospitalization and mortality rate will be assessed in both groups. Participants/Inclusion and exclusion criteria: All patients with Covid-19 symptoms in patients with the history of close contact with suspected people in the last 14 days fever pulmonary involvement normal or reduced cbc reduced lymphocyte, positive PCR exclusion criteria: patients with type I diabetes Ketoacidosis decompensated heart failure severe kidney failure (GFR<30 ml/min) metabolic acidosis severe respiratory failure immediate need for intubation Intervention groups: control group: received standard regimen for COVID-19 metformin group: received standard regimen for COVID-19 plus metformin 500 BID Main outcome variables: decrease need to hospitalization; decrease ARDS symptoms; decrease mortality