Which type of insulin has the longest duration of action among those listed?

Lantus, a long-acting insulin, is known for its prolonged duration of action, typically lasting up to 24 hours. It is designed to provide a steady release of insulin throughout the day and night, helping to manage blood glucose levels effectively in individuals with diabetes. The steady pharmacokinetic profile of Lantus means it does not have a pronounced peak, which can reduce the risk of hypoglycemia compared to insulins that peak more rapidly.

In contrast, Humalog is a rapid-acting insulin with a much shorter duration, usually around 3 to 5 hours, and is mainly used for controlling blood sugar spikes during meals. NPH, an intermediate-acting insulin, typically lasts about 10 to 16 hours and may not provide consistent coverage over a full day. Regular insulin has a duration of action of approximately 6 to 8 hours, making it less suitable for long-term management without additional doses.

Therefore, Lantus stands out as the insulin option with the longest duration of action, providing the benefit of once-daily dosing for stable glycemic control.