A double-blind randomized trial included 60 participants with a hemoglobin A1c ( HbA1c ) level higher than 7.5 % , a body mass index ( BMI ) between 25 and 35 Kg/m ( 2 ) , a C-peptide level 1.0 ng/mL , and a diagnosis of type 2 diabetes mellitus ( T2DM ) for at least 6 months .