Which statement correctly describes lispro or Humalog insulin?

• A. It is a rapid-acting insulin with onset around 30 minutes and duration 3-5 hours
• B. It is a long-acting insulin with no defined peak
• C. It is a short-acting insulin with onset 1-2 hours
• D. It is an intermediate-acting insulin with peak 6-14 hours

Answer: (A)

Lispro (Humalog) is a rapid-acting insulin analog designed to cover meals by acting quickly after injection. It is used to blunt the rise in blood glucose that follows eating, so it’s taken right before a meal. Its effects start relatively fast—around 15 to 30 minutes after injection—peaking in about 1 to 2 hours, and lasting roughly 3 to 5 hours. This rapid onset and short duration match the needs of post-meal glucose control, without providing long-lasting basal effects.

That’s why the statement describing lispro as a rapid-acting insulin with onset around 30 minutes and duration 3-5 hours is the best fit. It contrasts with long-acting insulins, which provide background coverage and have no defined peak, and with other insulins that have slower onsets or longer durations.