INS and type 1 diabetes mellitus: The variability in response to metformin observed in our study is consistent with the with the broader literature, which emphasizes the need for individualized therapeutic strategies in T1D, especially in those with overlapping characteristics of T1D and T2DM, often referred to as "Double Diabetes." Our findings indicate that metformin is particularly effective in improving insulin sensitivity and metabolic parameters in obese T1D patients, suggesting that even in the context of insulin deficiency, insulin sensitizers like metformin can be beneficial.