Insulin Lispro is an Insulin that helps lower after-meal glucose levels. Insulin is produced by specific cells in the pancreas called beta cells.  Its job is to help the body use or store the glucose that’s derived from carbohydrates in the diet.  Insulin is a hormone that works by lowering levels of glucose (sugar) in the blood.  When the body doesn’t produce insulin (as in the case of type 1 diabetes) or when it becomes resistant to using insulin properly (as happens with gestational and type 2 diabetes), cells are no longer able to access the energy they need and glucose builds up in the blood, which can result in serious chronic complications of uncontrolled diabetes.

Individuals are prescribed insulin as a medication to control their diabetes.  It is used to keep blood glucose levels in the recommended range.  If you’re prescribed Insulin Lispro to treat your diabetes, it can help to understand the characteristics and categories of this type of insulin and the important role the hormone plays in your health.The pancreas produces insulin in two different ways:

  • Basal insulin(sometimes called background insulin) it regulates glucose levels between meals and is released 24 hours a day, whether or not a person eats.
  • Bolus insulinis released by the pancreas in direct response to the ingestion of food in order to manage the rise in blood glucose that immediately follows.

Insulin Lispro is a bolus insulin which lowers after-meal glucose levels.  Insulin Lispro is manufactured by the pharmaceutical company Eli Lilly right here in the United States.  Eli Lilly’s Insulin Lispro is a bioequivalent to Eli Lilly’s Humalog.  Advanced Diabetes Supply carries Eli Lilly’s Insulin Lispro.

Also, know there are two types of bolus insulin: rapid-acting insulin and short-acting insulin.  Insulin Lispro is rapid acting insulin, which means it is

  • Is absorbed quickly from your fat tissue (subcutaneous) into the bloodstream.
  • Is used to control the blood sugar during meals and snacks and to correct high blood sugars

Now, to understand how Insulin Lispro works in your body you must know that insulin has an action curve with three phases:

  • Onset: How much time lapses between when the insulin is injected and when it starts to affect blood sugar levels; amount of time between your injections and when the insulin starts to lower your blood sugar.
  • Peak:The point at which insulin is working at maximum capacity.
  • Duration: How long insulin continues to work after taking effect.

With Insulin Lispro being a rapid-acting insulin it is taken at mealtimes and starts working in 15 minutes or less.  It peaks in 30 minutes to 90 minutes, and the effective duration and it remains in the bloodstream for up to 3 to 5 hours.

Because it starts working so quickly, rapid-acting insulin is generally taken within 15 minutes of eating — either within the 15 minutes before a meal or as much as 15 minutes after starting to eat.

Storage of Insulin: You must store all unopened insulin products in the refrigerator.  Refrigerate at 36° to 46°F (2° to 8°C).  Do not freeze the drug.  Opened Insulin Lispro vials may be stored in the refrigerator or at room temperature.  Opened Insulin Lispro cartridges and prefilled pens can only be stored at room temperature and should not be refrigerated.  Throw away all Insulin Lispro in use after 28 days, even if there is insulin left.  Also, throw away all insulin products after the expiration date on the package.

Insulin Delivery:  Insulin is usually injected into the fatty tissue just under the skin.  This is called subcutaneous tissue.  The body areas used most commonly for insulin injections or to insert an insulin pump infusion set are the abdomen, buttocks, and thighs.  Insulin can be placed in the body three ways:

  • Insulin vial and syringe.  The traditional way of taking insulin, using a syringe to draw insulin from a vial and inject it.
  • Insulin pens and dosing devices.  Insulin pens are usually the size of a large fountain pen. Some are reusable, and some are disposable. Disposable pens come pre-filled with insulin. Reusable models use a cartridge filled with insulin.
  • Insulin pump.  Insulin pumps are small, computerized, mechanical devices about the size of a pager. You wear it on your belt or in a pocket.   It delivers a steady stream of rapid- or short-acting insulin by pumping it to your body 24 hours a day through a needle attached to a flexible plastic tube.  Whenever you eat, you press a button on the pump to give yourself bolus insulin.  If you are presently on an Insulin Pump and your pump supplies are being billed to your Medicare Part B benefit, Advanced Diabetes Supply can service you for Insulin Lispro with a prescription from your prescriber.


When insulin is prescribed by your physician, it is important that the method of delivery be individualized.  Expense and insurance coverage may influence your choice, as well as convenience and level of manual dexterity.  Having your insulin billed to your Medicare Part B benefit may save you in out-of-pocket expenses.  Also, having your insulin billed to your Medicare Part B benefit will help avoid costs that affect your Part D / Pharmacy Benefit Doughnut hole.  Make sure to work with your physician and your diabetes care team to choose and learn to use the best method for you.

By, Halle Elbling, MS, RDN, CDE



American Diabetes Association. Insulin basics. Updated 2019.

American Diabetes Association. Insulin & other injectables. Updated 2019.