Limiting postprandial glucose (PPG) excursions is an important aspect of overall glycemic control. Rapid-acting insulin analogues (RAIAs) aim to mimic the physiologic action of endogenous insulin observed in individuals without diabetes and prevent excessive PPG excursions. However, many people with type 1 diabetes and type 2 diabetes treated with RAIAs do not achieve glycated hemoglobin (A1C) targets, and there is an unmet need for further improvements in PPG control. Current RAIAs have a delayed onset and a longer duration of action compared with endogenous insulin secreted in response to meals. Approaches to developing new mealtime insulins with accelerated absorption kinetics include changing the route of administration (i.e. via inhalation) and changing the insulin formulation. Fast-acting insulin aspart (faster aspart) is a novel formulation of insulin aspart (IAsp) containing the excipients niacinamide and L-arginine. Faster aspart has an earlier onset of insulin exposure and a greater early glucose-lowering effect than IAsp. In large clinical trials, mealtime faster aspart demonstrated noninferiority to IAsp with respect to A1C reduction and provided superior PPG control with no increase in overall severe or blood glucose-confirmed hyperglycemia. In addition, faster aspart administered up to 20 min after the start of a meal was noninferior to mealtime IAsp in terms of A1C control, highlighting the opportunity for postmeal dosing. Faster aspart is the first of a new generation of mealtime insulins to be approved in Canada for the treatment of adults with type 1 diabetes and type 2 diabetes, and it is included in the 2018 Diabetes Canada clinical practice guidelines.