Normally your pancreas produces all the insulin your body needs. When you have type 1 diabetes, however, your pancreas does not produce any insulin. You must get insulin from an outside source.

When you have type 2 diabetes, your body doesn't produce enough insulin, and your body can't use it well. You may need to supplement your body with insulin from another source. The insulin that you take is made in a laboratory so that it is identical to human insulin.

Supplemental insulin:
  • must be injected and cannot be taken by mouth
  • is necessary for people with type 1 diabetes
  • may be necessary for women who have gestational diabetes
  • may be necessary for people who have type 2 diabetes
  • comes in several types, which vary in how fast they work, when their peak action occurs, and how long they last

Most people who have diabetes need one to four insulin shots a day. How quickly or slowly insulin works depends on:

  • the type of insulin
  • your body's own response
  • the type and amount of activity you do
  • the length of time between your shot and physical activity
  • where on your body you inject the insulin

You'll need to monitor your blood glucose to know whether your diabetes medication is working.

Written by award-winning health writer Bobbie Hasselbring

Reviewed by Beth Seltzer, MD

Last updated June 2008