This paper investigates the applicability of tubebased robust MPC to control the blood glucose concentration in type 1 diabetic subjects through simulation studies. An existing, widely used metabolic simulation model is adopted and extended with several physiologically motivated uncertainties to account for the underlying intra?patient variability observed in real patients. Results on a virtual subject show that robustness to uncertainties can be improved and the risk of hypoglycemia reduced, without increasing the online computational demands compared to the conventional model predictive control approach.