Metformin hcl 500 mg is one of the most widely prescribed medications for type 2 diabetes, often taken for years or even decades. Generally, it is considered safe for long-term use and is effective at controlling blood sugar, reducing insulin resistance, and lowering the risk of diabetes-related complications. Some research even suggests it may have protective effects against cardiovascular disease and certain cancers.

However, like any medication, long-term use comes with potential risks. One common issue is vitamin B12 deficiency, which can occur after several years of treatment and may lead to anemia or nerve problems if left untreated. Rarely, metformin may cause lactic acidosis, a serious condition, though this is extremely uncommon in patients with normal kidney function.

To stay safe, patients should have regular kidney function tests and vitamin B12 levels checked. With proper monitoring, metformin remains a safe and effective long-term therapy for most people.