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Type 1 Diabetes: Insulin Treatment


Insulin and Type 1 Diabetes

Insulin is the only hormone in the body that can lower blood glucose. Without it, we would not survive: The carbohydrates from our diet would lead to potentially dangerous accumulation of glucose levels in our bloodstream.

Type 1 diabetes completely damages the pancreas, an organ responsible for making insulin. For that reason, people with type 1 diabetes cannot produce any insulin on their own. Every person with type 1 diabetes depends on injections of insulin so that glucose can be used as energy in the body. Insulin is vital to life!


Good to Know:

People who have recently been diagnosed with type 1 diabetes might produce a small amount of insulin for a short period of time on their own. Even so, the doctor will start long- and short-acting insulin treatments right away to get glucose levels into a normal range as quickly as possible.


What types of insulin are available?

Two major types of insulin are used to treat people with type 1 diabetes: short-acting and long-acting insulin. These two types are described in the table below.

The names and products below are intended as a reference and for educational purposes only.


Types of Insulin


How They Work

When They're Taken


Long-Acting ("Basal") Insulin


Basal insulin keeps blood glucose at a safe, constant level when the person is not eating.

Once or twice a day, depending on which type is prescribed (see examples).

  • Glargine is usually given once a day.

  • Detemir  is usually given twice a day.

  • NPH is an older type of insulin given twice a day.

Short-Acting ("Bolus") Insulin

Nutritional Insulin

Nutritional insulin helps the body digest carbohydrates from meals.

Up to 15 minutes before each meal. Short-acting insulin is most effective about one to two hours after it’s injected, and is nearly gone by four hours. That’s why it is ideal to take before a meal.

  • Lispro

  • Aspart

  • Glulisine

  • Regular insulin is sometimes used, but it must be given at least 30 minutes before a meal.

Correctional Insulin

Correctional insulin—like its name suggests— corrects high blood glucose by bringing it down to healthy levels.

Similar to nutritional insulin.

Similar to nutritional insulin.


How do I know how much insulin to take?

How do I know how much insulin to take?Each person will have a personalized treatment plan for taking insulin, in consultation with their health care provider. While the specific details of the treatment plan will differ for each, the doctor will usually make sure that roughly half of the daily insulin a person takes is long-acting, while the other half is short-acting. However, this may also depend on the person’s needs.

Determining the proper dose of nutritional insulin:

Sample calculation: Imagine that your dosing formula requires you to inject one unit of insulin for every 10 grams of carbohydrates that you eat or drink. Sample dose calculations are shown below, but it is important to remember that these are unique for each person.

Important note: Each person has a different insulin requirement. Contact your doctor if you are unsure of your doses.

 How much nutritional insulin will you need if you eat an entire sandwich that consists of 60 grams of carbohydrates?

  • For every 10 grams of carbohydrates, you will need one unit of insulin.

  • This sandwich contains 60 grams of carbohydrates: 60 g  ÷ 10 g = 6.

  • You will need six units of nutritional insulin.


Determining the proper dose of correctional insulin:

Sample calculation: Imagine that your dosing formula requires you to inject one unit of correctional insulin for every 25 mg/dl that your blood glucose is over a target level of 125 mg/dl.


You test your blood glucose before dinner and see that it’s 175 mg/dl. That’s high!


How can you lower it? How much correctional insulin should you inject before eating dinner?

  • First, determine how far off target your blood glucose is right now:

Actual Blood Glucose – Target Blood Glucose = Difference

175 mg/dl–125 mg/dl    = 50 mg/dl

  • For every 25 mg/dl of difference, you’ll need to inject one unit of insulin. So:

50 mg/dl ÷ 25 mg/dl = 2.

  • You should inject two units of correctional insulin before eating.


This sounds complicated. How many injections will I need every day?


At first, you might feel overwhelmed by the prospect of calculating doses of insulin and giving daily injections. If you aren’t sure where to begin, ask for help! Doctors, nutritionists and diabetes educators have many useful tricks for teaching patients and their families how to measure and give injections of insulin. Before long, the process will become as routine as brushing your teeth before bed.


Recommended treatment schedule

Most people with type 1 diabetes are recommended a treatment schedule known as “intensive insulin therapy,” which requires four injections a day. As long as people with type 1 diabetes pay close attention to the number of carbs they eat and drink, this method allows a great deal of flexibility with regards to the types of food they eat, when they eat it and how much they eat.

Here’s how it works:

  • The long-acting insulin is typically taken at bedtime.

  • Nutritional and correctional insulin are taken before each meal. The amount of insulin given is based on how many carbohydrates are in the meal and the blood glucose reading before the meal.

  • The person tests their blood glucose before each insulin injection to ensure the doses are adequate.


Other treatment schedules

For various reasons, some might prefer a treatment schedule that requires just two to three injections a day. The advantage of fewer injections, however, is offset by the stricter meal schedule that these people follow. Those who choose this method are recommended to eat at the same time every day, and they may be limited in the amount of carbs in each meal. If these people do not stick to a regular eating schedule, there’s a good chance that they will experience dangerous drops or rises in blood glucose. Talk with your doctor to see which injection schedule would work best for you.


What it all means

People with type 1 diabetes should work closely with their doctors and notify them as soon as possible of changes in lifestyle, including exercise regimens, weight gain or loss, dietary changes, illnesses or other medications.

Nutritionists and diabetes nurse educators are available to help patients learn how to determine their doses and make sure their current settings are working.

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