Summary of Different Types of Insulin Used for Diabetes Treatment

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Many Forms of Insulin are Used in Patients with Diabetes

Insulin has long been a mainstay of treatment for lowering blood sugar in patients with diabetes. It is used primarily in type 1, type 1.5 diabetes or LADA, and may sometimes be used in type 2 and gestational diabetes during pregnancy.

Initially, insulin was derived from animal sources like beef or pork, but now is made synthetically in labs. There are many different kinds of insulins classified according to their onset and duration of action. This takes into account how long each insulin takes to lower blood sugar and how long the effects last.

Rapid-Acting Insulin

Rapid acting insulin works quickly to lower blood glucose. It is a synthetically-designed analog of human insulin, similar but with a slight change in the chemical structure. Rapid insulin mimics the way insulin secreted by the pancreas works at meal time in a person who does not have diabetes. Generally, rapid acting insulin will:

  • Start working 10 to 15 minutes after injection.
  • Reach maximum effectiveness 30 to 90 min after injection.
  • Last for three to five hours.

Rapid-acting insulin is usually taken before each meal, called a bolus dose, to help prevent spikes in blood glucose levels after eating. Because this insulin starts working so quickly, patients with diabetes must eat within a few minutes of injection to prevent hypoglycemia, or low blood sugar.

Rapid insulin is available from three different drug companies. Novo Nordisk makes Novolog, also known as insulin aspart. Patients taking Novolog are recommended to eat within 5 to 10 minutes of the injection. Humalog is insulin lispro, and is made by Eli Lilly and Company. According to the prescribing information, Humalog should be taken 15 minutes before a meal or immediately afterwards. Apidra, called insulin glulisine, comes to the market from Sanofi-Aventis. Apidra should be taken within 15 minutes before starting a meal or 20 minutes afterward.

All three of these rapid insulins can be taken via syringe or insulin pump, and are also available in an injectible pen device.

Fast-Acting Insulin

Regular insulin, or insulin R, is the original type of insulin and is now considered fast acting when compared to all the others. This type of insulin:

  • Starts working 30 to 60 minutes after injection.
  • Becomes most effective at 2 to 4 hours after injection.
  • lasts 5 to 8 hours.

There are two brands of insulin R: Humulin, made by Eli Lilly and Company, and Novolin, made by NovoNordisk.

Intermediate-Acting Insulin

Intermediate-acting insulin works more slowly than regular and fast-acting insulins. This form of insulin is known as insulin N or NPH. Insulin N:

  • Starts to work one to three hours after injection.
  • Reaches maximum effectiveness in eight hours.
  • Lasts approximately 12 to 16 hours.

There are two brands of NPH insulin: Humulin and Novolin. They are usually taken once or twice daily.

Long-Acting insulin

Long acting insulin lasts for nearly a full day in the body. These are sometimes called basal insulins because they supply a base level of insulin that controls blood sugar when the patient is not eating. This type of insulin:

  • Starts working about one hour after injection.
  • Works continuously with no peak of effectiveness.
  • Lasts about 20 to 26 hours in the body.

Lantus insulin, known as insulin glargine, is made by Sanofi-Aventis. It is available in pen or vial forms. Levemir is called insulin detemir and is made by Novo Nordisk, and is also available in pen or vial forms.

These long-acting insulins are taken in once daily injections, though some patients will split higher doses to take twice daily. Long-acting insulins cannot be mixed with other insulins or used in an insulin pump.

Combination Insulin

Some insulin products are available that combine an intermediate insulin with either a fast or rapid acting insulin. Available products include

  • Humulin 70/30 and Novolin 70/30, a pre-mixed insulin containing 70% NPH insulin and 30% regular insulin
  • Humalog Mix 75/25, a pre-mixed insulin containing 75% intermediate insulin with 25% Humalog
  • Humalog Mix 50/50, a pre-mixed insulin containing 50% intermediate insulin with 50% Humalog
  • Novolog Mix 70/30, a pre-mixed insulin containing 70% intermediate insulin and 30% Novolog

Use of Insulin

Many type 1 diabetics that do not use an insulin pump delivery system use two different types of insulin in what is known as a basal-bolus insulin therapy. A long- or intermediate-acting insulin keeps normal blood sugar levels relatively constant, while a rapid- or fast-acting insulin smooths out the spikes during the day that result from eating a meal.

With the many different types of insulins for diabetes treatment that are available, patients often have questions about which is the right insulin for them. Anyone with questions or problems regarding insulin or diabetes should contact their healthcare provider.


Types of Insulin. National Diabetes Information Clearinghouse. Accessed September 8, 2010.

Novo Nordisk. Accessed September 9, 2010.

Eli Lilly and Company. Accessed September 9, 2010.

Sanofi-Aventis. Accessed September 9, 2010.

Joslin Diabetes Center. Accessed September 9, 2010.