Metformin has robust glucose-lowering effects and multiple benefits beyond hypoglycemic effects. It can also be used in combination with various hypoglycemic drugs and is cost effective. In the absence of the strong indications of glucagon like peptide-1 receptor agonist (GLP-1RA) or sodium glucose cotransporter 2 inhibitor (SGLT2i) for cardiorenal protection, metformin should be used as the first-line pharmacological treatment for newly diagnosed type 2 diabetes and the basic drug for the combined treatment of hypoglycemic drugs. Metformin does not increase the risk of liver and kidney function damage, but patients with renal dysfunction should adjust the dosage of metformin based on estimated glomerular filtration rate (eGFR) levels. Moreover, the correct use of metformin does not increase the risk of lactic acidosis. Because long-term use of metformin is associated with a decrease in vitamin B₁₂ levels, patients with insufficient intake or absorption of vitamin B₁₂ should be regularly monitored and appropriately supplemented with vitamin B₁₂. In view of the new progress made in the basic and clinical research related to metformin, the consensus updating expert group updated the consensus on the basis of the Expert Consensus on the Clinical Application of Metformin (2018 Edition).

Metformin; Diabetes mellitus, type 2; Clinical practice; Consensus