Metformin is one of the oldest antidiabetic medications, commonly used in the management of type 2 diabetes. Its mechanism of action is based on reducing glucose production in the liver, decreasing insulin resistance, and increasing insulin sensitivity. The drug has been studied extensively and has been shown to be effective in lowering blood glucose levels without increasing the risk of hypoglycemia. It has been used for the treatment of obesity, gestational diabetes, and polycystic ovary syndrome. According to current guidelines, metformin can be used as the first‑line agent in the management of diabetes; however, in individuals with type 2 diabetes who would benefit from cardio‑renal protection, newer agents, such as sodium‑glucose cotransporter‑2 inhibitors and glucagon‑like peptide‑1 receptor agonists, are favored as the first‑line therapy. The novel classes of antidiabetic medications have demonstrated significant positive effects on glycemia with added benefits in patients with obesity, renal disease, heart failure, and cardiovascular disease. The emergence of these more effective agents has significantly altered the way diabetes is managed, thus prompting re‑evaluation of metformin as the initial therapy for all patients with diabetes.