INS and type 2 diabetes mellitus: Moreover, in the Restoring Insulin Secretion study, while 12 months of metformin or 3 months of insulin glargine followed by 9 months of metformin slowed β-cell failure in adults with prediabetes and type 2 diabetes, β-cell failure continued in the identically treated youth, findings that would support more aggressive treatment approaches for youth-onset type 2 diabetes [11].