Which statement correctly describes lispro (Humalog) insulin?

• A. It is rapid-acting with onset around 15 minutes and is given before meals
• B. It is intermediate-acting and peaks in 4 to 10 hours
• C. It has no onset and is given once daily
• D. It should be given after meals routinely

Answer: (A)

Lispro is a rapid-acting insulin analog designed to match the quick rise in blood glucose that comes with a meal. Its effects begin within about 15 minutes, rise to peak in roughly 1–2 hours, and then wane over about 3–5 hours. Because of this rapid action, it’s taken right before meals (or just as you start eating) to cover post-meal glucose increases. That timing is essential—it should not be given after meals routinely, since the goal is to blunt the spike that occurs when you eat.

This differs from intermediate-acting insulins, which have a slower onset and longer peaks, and from long-acting insulins that are given once or twice daily for basal coverage. Lispro does have a clear onset, so statements claiming “no onset” or “given once daily” aren’t accurate.