Which insulin type has a duration of action of 16 hours?

NPH insulin, or Neutral Protamine Hagedorn insulin, is characterized by its intermediate duration of action, typically lasting around 16 hours. This type of insulin is commonly used in managing blood glucose levels in individuals with diabetes by providing a sustained release of insulin to cover both basal and prandial (mealtime) needs.

NPH has a peak action time that occurs approximately 4 to 12 hours after administration, making it effective for controlling glucose levels throughout the day when used in conjunction with short-acting insulins or oral hypoglycemics.

The other insulin types listed do not match this duration of action: Regular insulin typically has a shorter duration of around 6 to 8 hours, Lispro is a rapid-acting insulin with a very brief duration of about 3 to 5 hours, and Glargine, while having a longer duration, can last up to 24 hours or more, providing a more stable basal insulin level throughout the day. Thus, NPH's specific duration of about 16 hours makes it the correct choice for this question.