Previous studies have shown that intra-dermal (ID) insulin administration results in a more rapid onset of action in comparison to subcutaneous (SC) administration as measured by glucose infusion rate (GIR) under glucose clamp conditions.The aim of this study is to investigate whether ID administration of regular human insulin or rapid-acting insulin analogue leads to reduced postprandial glycemic excursions in comparison to SC application under highly standardized experimental conditions. Effects on the occurrence of hypoglycemia will also be investigated, as well as pK and pD comparisons between different insulin formulations administered ID. This is a mono-center, open-label, randomized, 5-period crossover study in patients with type 1 diabetes