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When is the best time to administer Humalog insulin?

Medically reviewed by Sally Chao, MD. Last updated on July 29, 2021.

Official answer


Humalog should be injected within 15 minutes before eating a meal or immediately after eating a meal. Humalog is a rapid-acting insulin that is used to help control blood sugar in people with diabetes. Insulin is most commonly administered as a subcutaneous (under the skin) injection.

Humalog is a brand name for insulin lispro, a rapid-acting insulin. It is approved by the U.S. Food and Drug Administration (FDA) for adults and children ages three years and older with diabetes mellitus.

Insulin is dosed in units. The exact dose to inject is determined by several factors, including your current blood sugar and how many grams of carbohydrate are being eaten. One risk of insulin injections is having your blood sugar drop too low (called hypoglycemia). This can happen when a person eats less than he or she planned. Rapid-acting insulins, like Humalog, can be administered immediately after eating, so you know how many grams of carbohydrates have actually been eaten.

Insulin is a hormone that helps your body to use the sugar (carbohydrates) from food for energy. In healthy individuals, insulin is made and stored in the pancreas. It is normally released by the pancreas in response to rising blood sugar levels. Individuals with diabetes mellitus don't make any or enough insulin of their own, so they must give themselves insulin.

There are different types of insulins. One way they differ is by their time profile: how rapidly they start to work, when their peak effects occur and how long their effects last.

Insulins are categorized as:

  • Rapid acting
  • Short acting
  • Intermediate acting
  • Long acting
  • Ultra-long acting

Most individuals with diabetes need to use more than one kind of insulin each day to achieve the best control of their blood sugar.

  • Insulin is often self-administered by individual subcutaneous injections either by drawing the insulin up into a syringe from a vial or by using a prefilled pen. All the insulin types may be given this way. Injection sites are rotated and include the abdomen, thigh, upper arm or buttocks.
  • Some people use an insulin pump, which delivers the insulin subcutaneously but as a continuous infusion.
  • In a medically supervised setting, such as a hospital, insulin may also be given as an intravenous (IV) infusion.

Humalog may be delivered all three ways.


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