Metabolic control analysis (MCA) is a theoretical framework which aims at quantitatively describing metabolic systems and at gauging distribution of control. MCA quantifies the role of each component of a system (e.g.: absorption rate of the fast insulin analogue, carbohydrate absorption through the gut, etc.) in controlling a variable of interest, most notably fluxes or concentrations, of the system itself, by computing the scaled coefficient of controls (CCs). CCs typically range from -1 to +1, and the greater their absolute value, the stronger is the control. Application of MCA to T1DM patients on CGM/CSII could quantify the individual role played by each components of the system, and may help in understanding and potentially overcome the hindrances to achieve stable and tight glucose control and to further develop CLC algorithms for optimal management of the disease.