What’s the Difference Between Basal and Bolus Insulin?

You may have heard the terms basal and bolus insulin in relation to treating type 1 diabetes. For those who are new to an insulin regimen, these terms may be confusing. Here we’ll clear up what these terms mean.

Basal-bolus therapy

People with type 1 diabetes, and even some with type 2 diabetes, have to use insulin throughout the day to manage their diabetes. If you are following a regimen using daily injections, you follow a basal-bolus injection schedule. Basal-bolus therapy is now also called intensive or flexible insulin therapy. 

The basal-bolus regimen attempts to mimic the way the body would naturally deliver insulin in someone who does not have diabetes.


Basal insulin

In the routine, a person takes basal insulin one or twice a day in order to regulate blood sugar levels throughout the day. Basal insulin is longer-acting. Examples of basal insulin include glargine, detemir, and degludec.

Bolus insulin

Before eating a meal, the person with diabetes injects bolus, or mealtime, insulin. This works to counteract blood sugar highs brought on by eating. The amount of insulin may need to be adjusted depending on how many carbs are consumed in the meal. Bolus insulin will be rapid-acting or short-acting. Examples of bolus insulin include aspart, lispro, and glulisine.

basal bolus


Advantages and disadvantages of basal-bolus therapy

With advancements in diabetes treatment, now 30 to 40 percent of people don’t use basal-bolus therapy but rather use a continuous glucose monitor and an insulin pump

The advantages of using the basal-bolus regimen versus pump therapy are:

  • More flexibility with how much you eat and when
  • Matches the way the body would naturally release insulin
  • Reduces A1C levels better than other treatments
  • Reduces dangerous blood sugar lows at night

The disadvantages of using the basal-bolus regimen versus pump therapy are:

  • More injections and blood sugar checks throughout the day
  • More difficult for children who are school-aged
  • Must keep insulin supply with you at all times
  • Must maintain a food log and calculate carbs

Speak with a  doctor about the right ways to regulate your blood sugar. Insulin acts differently for each person, so you may need to adjust accordingly. If you feel that basal-bolus therapy is not working for you, talk to your doctor about switching to insulin pump therapy.