The HbA1c cutoff for diagnosing Type 2 diabetes is 6.5% or higher. With your HbA1c at 6.8% and a fasting blood sugar reading of 127 mg/dL, your levels fall within the diabetic range. Therefore, Metformin would be prescribed as a treatment measure to manage your blood sugar, rather than a preventive one. Metformin helps your body use insulin more effectively and lowers glucose production. Along with medication, adopting lifestyle changes like a balanced diet and regular exercise is essential. Please consult your doctor to confirm this diagnosis and discuss starting a personalized treatment plan.