Faster-acting insulin aspart (faster aspart) is an ultra-fast acting insulin which contains insulin aspart (IAsp) in a new formulation with two additional excipients (niacinamide and arginine) added. This results in a faster initial absorption both after s.c. injection and infusion due to increased early insulin monomer formation in the subcutaneous space. In Pharmacokinetic/dynamic (PK/PD) studies, the observations in human subjects shows that faster aspart elicits a twice as faster onset of appearance in the bloodstream after injection, two-fold higher early exposure and 74% greater insulin action within 30 min compared to IAsp. This has in the phase 3 randomised clinical trials for faster aspart (the onset programme) consistently translated into improvements in postprandial plasma glucose (PPG) in both type 1 and type 2 diabetes. Conversely leading to statistically significantly greater or non-inferior HbA1c reductions in type 1 diabetes and comparable reduction in type 2 diabetes (T2D) with-out increasing the rates of hypoglycaemia versus IAsp. In addition faster aspart has demonstrated non-inferior HbA1c control even when dosed up to 20 minutes after the beginning of the meal compared to IAsp dosed at the beginning of the meal. Potentially allowing for more flexibility in the dosing regimen for patients who need it under certain circumstances. Overall, faster aspart appears twice as fast in blood stream after injection which leads to the improved glycaemic control after a meal as seen with faster aspart, versus IAsp, in the onset clinical trial programme, thereby providing an incremental innovation for patients in need of mealtime insulin.