Administration of pioglitazone (30 mg once daily) together with insulin (49 units/day) to people with T1D (HbA1c 7.2%, fasting and postprandial plasma glucose 117 mg/dL and 164 mg/dL, respectively, BMI 19.6 kg/m2, diabetes duration 7 years) for 24 weeks lowered HbA1c and postprandial glucose by 3% and 8%, respectively, whereas fasting plasma glucose, insulin requirements, and BMI remained unaltered. Here, INS is linked to type 1 diabetes mellitus.