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How long does it take for Humalog to work?

Medically reviewed by Sally Chao, MD. Last updated on July 22, 2024.

Official answer

by Drugs.com

Humalog (insulin lispro) is a rapid-acting insulin prescribed to improve blood sugar control in people with diabetes. In general, Humalog starts to work about 15 minutes after it is injected, and peak effects happen after an hour or two. Humalog's effects usually last 2-4 hours. However, this can be different for everyone, or even vary for the same person from one injection to another.

If you have diabetes, your body does not produce enough insulin or does not respond to insulin appropriately. Insulin is a hormone that enables your body to use the energy from the food you eat. You may have to give yourself insulin injections under the skin (subcutaneously), usually several times a day, to control your blood sugar.

The injections can be given under the skin of the abdomen, thigh, upper arm or buttocks. The exact dose is determined by several factors, including your current blood sugar as well as what (and how much) you are eating.

Factors that can influence the timing of insulin's effects include:

  • The injection site
  • Blood flow to the injection site
  • Body temperature

For example, exercising after giving yourself an insulin injection would increase blood flow and body temperature. Both of these factors could potentially increase the rate of insulin absorption from the injection site, which might shorten the time for initial effects and increase the degree of peak effects of the insulin.

To optimize the effects of insulin, coordinate the timing of your insulin injections with mealtimes and workouts.

References
  1. Food and Drug Administration (FDA). Drugs@FDA: FDA-Approved Drugs. HUMALOG (insulin lispro injection). November 2019. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/020563s196s198s199,205747s022s025s026lbl.pdf. [Accessed July 7, 2021].
  2. American Diabetes Association (ADA). Insulin basics. Available at: https://www.diabetes.org/healthy-living/medication-treatments/insulin-other-injectables/insulin-basics. [Accessed July 12, 2021].

Read next

Does Humalog need to be refrigerated?

Humalog (insulin lispro) should be stored in a refrigerator (36° to 46°F [2° to 8°C]) until it is opened, but do not freeze it. Once your Humalog vial, cartridge or prefilled pen is in use, it can be stored at room temperature, below 86°F (30°C), for 28 days. Discard it after 28 days. Continue reading

Is Admelog the same as NovoLog?

No, Admelog (insulin lispro) is not the same as NovoLog (insulin aspart). These insulins have different chemical structures but they are both man-made, rapid-acting forms of insulin used to help lower mealtime blood sugar (glucose) levels in patients with diabetes. Continue reading

What type of insulin is Humalog?

Humalog (insulin lispro) is a fast-acting insulin. It begins working to lower blood sugar levels about 15 minutes after injection, reaches a peak in about 1 hour, and continues to work for 2 to 4 hours. Humalog helps to control the blood sugar spikes that may occur during mealtime. It is used within 15 minutes before eating or right after eating a meal. Continue reading

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