Types of insulin

Photo of a man (PantherMedia / Christine Langer-Pueschel)

Insulin therapy is essential for everyone who has type 1 diabetes and some people who have type 2 diabetes. Various types of insulin are available. They differ in terms of how quickly and how long they are effective, as well as in their chemical structure.

Some types of insulin work quickly (short-acting insulin or rapid-acting insulin), while others only start to work after a certain amount of time, and then work over a longer time period (long-acting or basal insulin).

Insulin can be extracted from the pancreas cells of pigs (porcine insulin) or cattle (bovine insulin) and prepared for use in humans. But nowadays most people use genetically engineered insulin for the treatment of diabetes. There are two types of genetically engineered insulin, known as human insulin and insulin analogues. Human insulin is similar to the insulin made in the human body. Insulin analogues have a different chemical structure, but they have a similar effect.

What are the different types of insulin?

The following types of insulin products differ in terms of how quickly and how long they are effective, as well as in terms of their chemical structure:

  • Short-acting insulin:
    Insulin analogues:
    Start working: about 5 to 10 minutes after injection
    Maximum effect: about 1 to 1.5 hours after injection
    Duration of effect: about 2 to 3 hours
    Regular insulins (human insulin, porcine insulin, bovine insulin):
    Start working: after about 15 to 30 minutes
    Maximum effect: about 1 to 3 hours after injection
    Duration of effect: about 4 to 8 hours
  • Intermediate-acting insulin (insulin analogues, human insulin or porcine insulin with delayed action due to addition of NPH (neutral protamine Hagedorn) or zinc):
    Start working: about 2 hours after injection
    Maximum effect: about 4 to 6 hours after injection
    Duration of effect: about 12 to 14 hours
  • Long-acting insulin (insulin analogues, human insulin, porcine insulin):
    This kind of insulin takes longer to start working. Peak activity and duration of effect depend on the way in which the action is delayed. Usually works for up to 24 hours.
  • Premixed insulin (insulin analogues, human insulin, porcine insulin):
    Short-acting insulin and intermediate-acting or long-acting insulin that has already been mixed.

Short-acting insulin – including regular insulin, insulin analogues and premixed insulin – is normally injected before meals. Some people wait a certain amount of time following the injection before they eat. Others vary the time interval between injecting and eating depending on their blood sugar levels.

Many people find fixed injection-meal intervals bothersome and difficult to stick to in everyday life. So far there is no evidence to show that blood sugar levels are better controlled if you stick to fixed injection-meal intervals.

Comparing human insulin and insulin analogues

Insulin analogues were introduced to the market in the 1990s. Compared to human insulin, they start lowering blood sugar somewhat sooner after being injected. For many years now there has been a debate about whether people with diabetes benefit from this. But research has not found any evidence to suggest they do.

If, for instance, a particular type of insulin were shown to prevent complications caused by poorly controlled blood sugar levels, that type of insulin would offer a clear advantage. It would also be an advantage if the insulin prevented strong fluctuations in blood sugar levels that lead to noticeably low or high blood sugar (hypoglycemia or hyperglycemia). Or if it made it easier for people to follow their daily treatment plan. But studies in this area suggest that insulin analogues and human insulin are equally effective in the treatment of diabetes.