Humalog Pen

insulin lispro

By Eli Lilly

What is this medication for?

Insulin is a naturally-occurring hormone made by the pancreas that helps our body use or store the glucose (sugar) it gets from food. For people with diabetes, either the pancreas does not make enough insulin to meet the body's requirements, or the body cannot properly use the insulin that is made. As a result, glucose accumulates in the bloodstream. Insulin injected under the skin helps to lower blood glucose levels.

Having good control of blood glucose levels is the key to reducing the risk of complications of diabetes (e.g., kidney disease, eye problems, nerve problems).

Long-term control of blood glucose levels is an important step in preventing diabetes complications such as stroke, heart disease, and kidney disease. This medication works best for people who are following a proper dietary and exercise plan.

There are many different types of insulin and they are absorbed at different rates and work for varying periods of time. Insulin lispro is a rapid-acting insulin. It takes about 10 to 15 minutes after injection to begin working and has its maximum effect between 30 minutes and 90 minutes. It stops working after 4 to 5 hours. It is used to help control blood glucose (sugar) in people with diabetes (type 1 or 2).



What form(s) does this medication come in?

Humalog Pen® is available as:

  • injectable solution
    • 3 mL prefilled disposable pens (100 units per mL)

How should I use this medication?


Your dose of insulin should be injected subcutaneously (under the skin), exactly as instructed by your doctor or diabetes educator. The dose of insulin is measured in units (U). Insulin lispro is injected under the skin within 15 minutes before or immediately after a meal. Longer-acting insulins are often used along with insulin lispro to cover the periods of time between doses of insulin lispro. There are many variations of insulin dosing.

Check to make sure you are injecting the correct insulin and dose, especially if you use other insulin with this medication.

Consult your doctor or diabetes educator for proper instructions for injecting insulin. The best places to inject insulin under the skin are on the upper arm, abdomen area (stomach), buttocks, or thigh. Never inject it into a vein or muscle. Rotate these injection areas in order to prevent thickening of the skin (which can happen if certain skin areas are used more frequently than others).

While using this medication, it is important to monitor your blood glucose level regularly, as directed by your doctor or diabetes educator.

Do not dilute or mix insulin lispro with other insulin or solutions without checking with your doctor first. Some forms of insulin cannot be mixed with insulin lispro, and insulin lispro should not be mixed with other insulins if it is in a cartridge or if it is to be used in an external insulin pump.

Insulin lispro should be clear and colorless. Do not use the insulin if you notice anything unusual in the appearance of the solution.


It is important to use this medication exactly as prescribed by your doctor. The timing of insulin with respect to your meals is crucial to keeping blood glucose under control and preventing unwanted side effects. If you miss a dose, contact your health care professional for advice.

Keep unopened bottles of insulin in the refrigerator until needed - they may be used until the expiration date on the label. Never allow insulin to freeze. Insulin that is currently in use may be kept at room temperature for 28 days only and then discarded. Do not expose insulin to extremely hot temperatures or to sunlight. Keep insulin out of reach of children.

Who should NOT take this medication?

Do not use this medication if you:

  • are allergic to insulin or any ingredients of the medication
  • have low blood glucose (hypoglycemia)
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