Insulin and Monitoring Blood Sugar

Insulin is a hormone made by the pancreas that allows sugar to pass into cells and be turned into energy. It is essential for survival. People with type 1 diabetes must take insulin every day to be able to make energy and control blood sugar levels. Insulin cannot be taken in pill form. The most effective way to take insulin is with injections. There are different methods of injecting insulin, including pumps, pens, and injectors.

Type of insulin

There are many different types of insulin. The type(s) you choose should be based on your lifestyle and a discussion with your diabetes team.

  • Rapid insulin, such as aspart, apidra and lispro
  • Short-acting (regular) insulin
  • Intermediate-acting insulin, such as NPH
  • Long-acting insulin such as glargine and detemir

Some insulins come premixed with a combination of long- and short-acting insulins. The type and frequency of insulin injections varies from person to person. You and your diabetes team will determine what is appropriate for you.

Proper storage for insulin

  • Unopened insulin should be kept in the refrigerator. Unopened insulin is good until the expiration date on the bottle.
  • Opened insulin can be stored in the refrigerator or at room temperature. Room-temperature insulin should be kept in a cool place away from direct sunlight. Opened insulin varies in the length of time it is stable at room temperature.

Injection schedules

These charts show the different types of insulin and how frequently they need to be taken. Courtesy of Dr. H. Peter Chase, author of Understanding Diabetes.

Insulin activities

Type of Insulin Begins Working Main Effect All Gone
(lasts 4 to 10 hours)
Humalog/NovoLog 10 to 15 minutes 30 to 90 minutes 4 hours
Regular 30 to 60 minutes 2 to 4 hours 6 to 9 hours
(lasts 10 to 20 hours)
NPH 1 to 2 hours 3 to 8 hours 12 to 15 hours
Ultralente 2 to 4 hours 6 to 14 hours 18 to 20 hours
(lasts 20 to 24 hours)
Lantus (Insulin Glargine) 1 to 2 hours 2 to 22 hours 24 hours
Pre-Mixed Insulins      
Lente 1 to 2 hours 3 to 14 hours 18 to 20 hours
70/30 NPH/Regular 30 to 60 minutes 3 to 8 hours 12 to 15 hours
75/25 NPH/Humalog 10 to 15 minutes 30 minutes to 8 hours 12 to 15 hours

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