Bolus Dose of Insulin

Woman injecting insulin into abdomen.
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A bolus dose of insulin is the dose of regular or rapid-acting insulin that is injected to cover the food you eat in a meal or a snack. This type of insulin begins to work quickly (usually withing 15-30 minutes) and lasts in the system for a shorter time period (around 2-4 hours). When an insulin pump is used, the bolus is given, as basal rate continues to be infused, to cover food intake. The bolus dose allows your cells to take in the glucose produced in digesting food so you maintain appropriate blood glucose levels

The Bolus Insulin is Meant to Mimmick a Well Functioning Pancreas

Injecting insulin with each meal may seem unnatural, but you are simply doing by injection what a normal pancreas does in releasing insulin in a person who doesn't have diabetes. In someone who does not have diabetes, the pancreas should be releasing a small amount of insulin continuously, day and night. This is referred to as a basal level of insulin. Then when you eat food, especially carbohydrates, the pancreas detects the increase in blood sugar and releases a bolus of insulin. The insulin then allows the cells to take in sugar, lowering the blood glucose level and allowing the cells to use it for fuel or store it. As a result, blood glucose levels stay within the normal zone and hyperglycemia is prevented.

People with diabetes, take exogenous insulin so that they can mimmic this system and maintain normal blood sugar levels. 

Taking Bolus Doses of Insulin

Bolus insulin, or mealtime insulin is meant for all people with type 1 diabetes, as they do not produce any of their own insulin. But sometimes, it is meant for people wtih type 2 diabetes, too. This can happen when blood sugars are elevated depsite optimized oral medications, lifestyle changes, etc. When this happens, your doctor will recommend an appropriate plan for injecting bolus doses of insulin at meals. Insulin must be injected because it is a protein and it would be broken down if taken in a pill. It can be injected by syringe, pen, or pump.

Your dose will be caluated based on a variety of factors, including blood sugar levels, and amount of carbohydrate eaten, etc. You may start with a fixed amount of insulin per meal, or perhaps your physician will provide you with an insulin-to-carbohydrate ratio, a ratio that is calculated to cover a specific amount of carbohydrates.. For example, if your insulin-to-carbohydrate ration is 1:10, that means, for each 10 grams of carbohydrate eaten, ,you would need to inject 1 unit of insulin. If you consumed 60 grams of carbohydrate for that meal, you would then "bolus" 6 units of insulin. 

Bolus doses are also used when blood glucose levels are too high, to lower the amount of glucose in the blood. This is referred to as a "correction factor." 

As always, every diabetes plan should be individualized based on a persons' lifestyle, blood sugars, cognitive abilities, age, etc. Your doctor or certified diabetes educator will also tell you when to take your bolus (usually given before the meal) and how to inject it safely and accurately. 

A Word from Verywell 

Work with your doctor to ensure you are on the right medications and that you understand when and how to administer them. While having to take a bolus injection when you eat is inconvenient, it is a key part of maintaining blood glucose control and preventing complications from diabetes. You are simply doing what the pancreas normally does and what our bodies expect to have happen when we eat and digest food. Everyone else in the room is giving themselves a bolus dose, even if they don't realize it. You just need a little technological help.

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Article Sources

  • Insulin Routines, American Diabetes Association, June 29, 2015. Accessed February 11, 2016.
  • The Basics of Insulin. Retrieved December 13, 2007, from American Diabetes Association.