Metformin could diminish insulin resistance, prevent immune hyperactivation and ARDS occurrence through the inhibition of the mTOR pathway. Furthermore, it could show anti-inflammatory effects and neutrophil reduction, blockade of mitochondrial ROS signaling pathway, cellular pH enhancement through endosomal Na+/H+ exchangers.The interference with viral endocytosis and viral penetration inhibition through the activation of MAPK and phosphorylation of ACE2 are among other metformin actions. The gene discussed is ACE2; the disease is acute respiratory distress syndrome.