Time-action of different insulins

Insulins Starts working Peaks 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



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

  • 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.

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

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