As first-line therapy in type 2 diabetes treatment, metformin, one of the oldest oral antidiabetic agents continues to be recommended by almost all current guidelines on the management of type 2 diabetes mellitus. Many experimental and clinical studies have demonstrated that metformin has additional pleiotropic benefits and favorable effects in different pathological conditions, including prediabetes, type 1 diabetes mellitus, and gestational diabetes mellitus. 

Many real-world studies and meta-analyses have also shown metformin to be safe and well-tolerated with cardioprotective and nephroprotective effects. Metformin has a multifactorial beneficial effect on cardiovascular risk factors such as reduction of insulin resistance, hyperglycemia, inflammation, blood pressure, dyslipidemia, endothelial dysfunction, diabetic thrombophilia, microalbuminuria, oxidative stress, and obesity. Recently, some studies have also suggested that metformin, along with the improvement of glucose homeostasis, may play a role in reducing the risk of cancer development, inhibiting the occurrence of neurodegenerative disease,and also prolonging the lifespan. 

Reference: Drzewoski J, Hanefeld M. The current and potential therapeutic use of metformin-the good old drug. Pharmaceuticals (Basel). 2021; 14: 122.