Clinical Effects and Benefits of Metformin in Type 2 Diabetes

Efficacy and Safety

The American Diabetes Association recommends metformin as a first-line treatment for type 2 diabetes, as it typically reduces HbA1c levels by 1.0% to 1.5% compared to placebo 1
Metformin is weight neutral or may even help with modest weight reduction, unlike many other diabetes medications 2
The American College of Cardiology notes that metformin helps decrease LDL cholesterol and triglyceride levels, improving lipid profiles 2, 3
Evidence suggests metformin treatment is associated with a reduction in major cardiovascular events in patients with type 2 diabetes 1

Metformin is contraindicated in patients with severe renal impairment (eGFR <30 mL/min/1.73 m²), liver dysfunction, hypoxemic conditions, severe infections, or alcohol abuse 1, 3
Gastrointestinal symptoms, such as bloating, abdominal discomfort, and diarrhea, are the most common adverse effects of metformin 5
Long-term use of metformin may lead to vitamin B12 deficiency, requiring periodic monitoring 5

The recommended starting dose of metformin is 500 mg once or twice daily, with gradual titration to minimize gastrointestinal side effects 6
Extended-release formulations of metformin can improve tolerability by reducing gastrointestinal side effects while maintaining efficacy 6
Dose adjustment is required for patients with reduced renal function (eGFR 30-45 mL/min/1.73 m²) 6