Which insulin has an onset of 1 hour with no peak effect?

The correct answer is the long-acting insulin, such as Lantus. Long-acting insulins are designed to provide a steady level of insulin over an extended period, minimizing fluctuations in blood glucose levels. The onset of long-acting insulins is approximately one hour after administration, but they do not have a peak effect; rather, they maintain a consistent, controlled insulin level for 24 hours or more. This characteristic makes them ideal for providing basal insulin coverage throughout the day and night.

In contrast, regular insulin has a different profile, with a quicker onset and a defined peak effect, typically occurring around 2 to 3 hours after administration. NPH insulin is an intermediate-acting insulin that has both an onset and a peak, with a peak effect typically seen several hours after administration. Rapid-acting insulins, while starting to work very quickly (within 15 minutes), also have a clear peak effect usually between 1 to 2 hours after injection. Therefore, the long-acting insulins stand out by providing a gradual release of insulin without a peak, which is essential for managing blood sugar levels in a stable manner.