Types of Insulin

Man filling a syringe with ins

Insulin is classified by how fast and how long it works in your body.

Many types of insulin are used to treat diabetes. Although available choices may seem a bit overwhelming at first, this guide can help you discuss your treatment with your doctor.

Insulin is classified by how fast and how long it works in your body.

Terms To Know

  • Onset – How quickly insulin lowers your blood sugar.
  • Peak Time – When insulin is at maximum strength.
  • Duration – How long insulin works to lower your blood sugar.

Your doctor will prescribe the best insulin or insulins for you based on several factors:

  • How active you are.
  • The food you eat.
  • How well you’re able to manage your blood sugar levels.
  • Your age.
  • How long it takes your body to absorb insulin and how long it stays active. (This is different for different people.)

If you have type 1 diabetes, you’ll likely take a combination of insulins. Some people with type 2 diabetes will also need to take insulin.

Different brands of insulin vary in onset, peak time, and duration, even if they’re the same type, such as rapid acting. Be sure to check the dosing information that comes with your insulin and follow your doctor’s instructions.

Types of Insulin
Insulin Type Onset Peak Time Duration Method
Rapid acting​ 15 minutes 1 hour 2 to 4 hours Usually taken right before a meal. Often used with longer-acting insulin.
Rapid-acting inhaled 10 to 15 minutes 30 minutes 3 hours Usually taken right before a meal. Often used with injectable long-acting insulin.
Regular/short
acting
30 minutes 2 to 3 hours 3 to 6 hours Usually taken 30 to 60 minutes before a meal.
Intermediate
acting
2 to 4 hours 4 to 12 hours 12 to 18 hours Covers insulin needs for half a day or overnight. Often used with rapid- or short-acting insulin.
Long acting 2 hours Does not peak Up to 24 hours Covers insulin needs for about a full day. Often used, when needed, with rapid- or short-acting insulin.
Ultra-long acting 6 hours Does not peak 36 hours or longer Provides steady insulin for long periods.
Premixed 5 to 60 minutes Peaks vary 10 to 16 hours Combines intermediate- and short-acting insulin. Usually taken 10 to 30 minutes before breakfast and dinner.

For more information about types of insulin and when to take them, talk to your doctor or diabetes educator.

Page last reviewed: March 25, 2021