Types of Insulin

Different types of insulin serve different purposes. Stockbyte/Getty Images

Types of Insulin:

It wasn’t that long ago that there were only a few types of insulin available for people with diabetes. But now there are many different types of insulin that serve a variety of purposes. To understand how the different types of insulin work in your body, you should first understand some basic terms.

  • The onset of insulin refers to the amount of time between your injection and when the insulin starts to lower your blood sugar.
  • The duration of insulin refers to how long the insulin will continue to work after it starts to take effect.
  • The peak refers to the point where the insulin is working at its maximum capacity or is the strongest.

Different Types of Insulin

There are different types of insulin for different purposes. Here are types that are currently available:

Rapid-acting insulin

Rapid-acting insulin is designed to begin working quickly, usually with an onset of about 15 minutes after injection. Rapid-acting insulin is often used immediately before a meal to offset the rise in glucose that occurs from eating. This insulin peaks about 1-2 hours after injection and lasts up to five hours.

Short-acting insulin

Short-acting insulin, also called regular insulin, has an onset of about 30 minutes and typically peaks in 2-4 hours and can last up to 8 hours.

Intermediate-acting insulin

There is only one intermediate-acting insulin on the market and it is called NPH.

In contrast to the clear fluid of the rapid and short-acting insulins, NPH has a cloudy consistency. This cloudiness results from insulin crystals in the solution. NPH has an onset of about 1-2 hours, peaks in about 8 hours with a duration of up to 16 hours but this duration can vary from person to person.

It is not uncommon for people taking NPH to also take a dose of regular or rapid-acting insulin to cover meals, which is also referred to as bolus insulin.

Long-acting insulin

Long-acting insulin has an onset of about 1 hour. Because it is designed to stay in the system longer than the other types of insulin, it does not have a “peak” action point. Once it takes effect, the intended purpose of long-acting insulin is to maintain a consistency that helps control blood glucose levels when you are not eating and especially during sleep. This long-term action is also referred to as basal insulin. Long-acting insulin typically has a duration of up to 24 hours and is usually supplemented with a rapid- or short-acting insulin to cover for rising glucose at meals.

Pre-mixed insulin

There are several pre-mixed insulins available that combine varying amounts of intermediate-acting insulin with rapid-action or short-acting insulin. These mixtures serve as a convenient way to obtain the benefits of both types of insulin while only injecting once.

These pre-mixed insulins have an onset of between 15 minutes and 1 hour, depending on the mix. The peak time varies and each can last up to 24 hours.


Insulin. American Diabetes Association. " Consumer’s Guide 2011. " Diabetes Forecast, January 2011, Vol, 64, No. 1.

Hieronymus, L. M.S.Ed., A.P.R.N., B.C.-A.D.M., C.D.E., Geil, P. M.S., R.D., C.D.E. "Types of Insulin. " Diabetes Self-Management, 2009.

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