The involved time lags caused by the patient dependent delayed insulin action were quantified for 10 patients. Therefore, patient-specific, in terms of appropriate insulin dosing for each patient, optimization studies were performed to find the optimal timing to deliver the bolus. An alternative, stepwise insulin regimen was considered and the optimization results indicate that it could provide a considerable alternative for closed loop applications. These results will be incorporated in future work into the control strategy (Dassau et al., 2006) that will be clinically evaluated.