Understanding insulin

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Learn where injectable insulin comes from and how it works.

Key points

  • All children and nearly all adults with diabetes receive biosynthetic human insulin products and insulin analogs.
  • Insulin is available in premixed doses that combine rapid -acting insulin with intermediate-acting insulin in fixed proportions.

Where does injectable insulin come from?

Insulin was first isolated and collected from the pancreases of cows and pigs for use in humans with diabetes. Since 1983, however, a product called biosynthetic human insulin has been available. This insulin is produced in a laboratory by introducing a man-made human gene into bacteria or yeast. This process produces insulin that is almost exactly the same as that created in the human pancreas.

Through further changes, man-made altered forms of insulin (called insulin analogs) differ from naturally incurring insulin by having different action times. Today, all children and nearly all adults with diabetes receive biosynthetic human insulin products and insulin analogs.

Insulin strength and packaging

In North America, insulin is usually produced at a concentration of 100 units/mL. Before giving insulin to your child, make sure to check the concentration. Insulin is available in three ways:

Vial
CartridgesPreloaded disposable pens
  • Used with needles (syringes);
  • Each vial holds 10 mL of insulin.
  • Used with insulin pen or insulin pumps;
  • Each pen cartridge holds 3 mL of insulin.
  • Each pen has a preloaded cartridge that hold 3 mL of insulin.
insulin vial illustration insulin cartridge illustration insulin preloaded disposable pen illustration

Insulin action times

Insulin analogs are generally described as:

  • rapid-acting (also referred to as fast-acting)
  • intermediate-acting
  • long-acting.

Insulin analogs are also described according to their course of action:

  • Onset is the time it takes for the insulin to start working.
  • Peak describes the period when the insulin is working at its strongest.
  • Duration describes the length of time before the effect of the dose wears off.
Table showing the different types of insulin, their appearance and their action times after injection in hours

Premixed insulin

Insulin is available in premixed doses that combine rapid-acting insulin with intermediate-acting insulin in fixed proportions. Premixed insulin is generally not recommended for children, because it does not allow for any flexibility in insulin dose adjustments and, therefore, does not allow for better blood sugar control compared to other insulin routines.

Last updated: October 17th 2016