Skip to main content

Time-action of different insulins

  • Insulins

    Starts working


    Stops working


    Humalog® (lispro)

    NovoLog® (aspart)

    Apidra® (glulisine)

    5 to 15 minutes

    1 to 2 hours

    2 to 4 hours


    Regular (R)

    30 to 45 minutes

    3 hours

    4 to 8 hours


    NPH (N)

    2 to 4 hours

    4 to 8 hours

    10 to 16 hours


    Intermediate-acting/rapid acting

    NPH and regular insulin

    5 to 15 minutes

    30 to 45 minutes

    1 to 2 hours/ some increase at 4 to 8 hours

    2 to 3 hours/

    4 to 8 hours

    10 to 16 hours

    10 to 16 hours


    Lantus® (glargine)

    Levemir® (detemir)

    2 hours

    No peak

    24 hours

    *The long-acting insulin may work the best between four and eight hours.

    **Lantus and Levemir cannot be mixed with any other insulin.

    How to help insulin work best


    The insulin you inject only lowers your blood glucose. It does not cross the placenta to your baby.

    • Take your insulin at the same time each day as directed.
    • Take your insulin every day, even if you feel sick. If you cannot eat normally because you are sick, see Sick day tips when taking insulin.
    • Don't change your meal plan, exercise, prescribed medications or insulin routines without talking to your health care provider.

    Pen devices

    Most insulins are available in a pre-filled pen you throw away after use. See the product insert for specific use guidelines.

  • Source: Source: Allina Health's Patient Education Department, Gestational Diabetes: When You Have Diabetes During Pregnancy, third edition, ISBN 1-931876-21-6
    Reviewed by: Reviewed by Allina Health's Patient Education Department experts
    First published: 11/27/2006
    Last reviewed: 01/20/2014