Please note: This information was current at the time of publication but now may be out of date. This handout provides a general overview and may not apply to everyone. 

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Am Fam Physician. 2000;62(9):2141

What is insulin?

Insulin is a hormone that controls the level of sugar (also called glucose) in your body. When you have type 1 diabetes, your body doesn't make enough insulin. This causes sugar to build up in your blood. Over time, high blood sugar levels can cause serious health problems, such as blindness, kidney problems and damage to the nerves that go to your legs and feet.

People with type 1 diabetes must take insulin. This helps them keep their blood sugar level as close to normal as possible. If you can do this, you can avoid or delay many of the serious health problems caused by diabetes.

How do I use insulin?

You can give yourself insulin with injections, an insulin pen or an insulin pump. There are different kinds of insulin. They all start working and keep working at different speeds. Your doctor will talk with you about what insulin to use. Your doctor might want you to use more than one kind of insulin every day. Some insulins can be mixed together.

What is a flexible insulin regimen?

A flexible insulin regimen is one that lets you adjust the timing and amount of insulin to meet your needs. With a conventional regimen, you take insulin at set times and have to follow a strict schedule. A flexible regimen allows for changes in your schedule and lets you adjust your insulin as needed. For example, you might increase the dose of insulin if you eat a meal with a lot of carbohydrates. Or you might lower your insulin dose if you are going to exercise. A flexible regimen also may help you keep tighter control over your blood sugar level.

A flexible insulin regimen has benefits, but it means you will have to make some extra effort. You must check your blood sugar level regularly and keep track of what you eat. This means counting the carbohydrates you eat. Your nurse, doctor or dietician can teach you how to count carbohydrates. You must also learn how your body reacts to insulin and how to adjust your dose. Too much insulin can give you hypoglycemia (blood sugar level is too low). Too little insulin can give you hyperglycemia (blood sugar level is too high). Both of these conditions can be dangerous.

When should I take insulin?

Your nurse, doctor or dietitian will talk with you about when to take insulin. Remember that some insulins start working faster, while others keep working longer. It's important to pay attention to the time between taking insulin and eating a meal. For example, regular insulin has to be taken 20 to 30 minutes before eating. Insulin lispro should be taken no more than 15 minutes before eating a meal because it works faster.

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