Types of Insulin
What Are the Differences?
The main differences among the various types of insulin mainly involve how quickly (or slowly) they start and stop working, and when they produce a peak effect. Rapid-acting insulins begin working very quickly, produce a sharp, fast peak, and stop working quickly. Short-acting insulins take a little while longer to start working, peak later, and stop working a little later. Both rapid- and short-acting insulins are used to control the increases in blood sugar levels that occur after meals. They are both taken before meals.
Intermediate-acting insulins start and stop working later than short- or rapid-acting insulins. They also peak later. They usually cover the background insulin needs for about half a day and are combined with a short- or rapid-acting insulin for mealtime use.
Long-acting insulins are much like intermediate-acting ones, except they work a little longer and usually produce less of a peak (or, in some cases, no peak at all). They usually cover the background insulin needs for the entire day and are combined with a short- or rapid acting insulin for mealtime use. Some people may need to take a long-acting insulin twice a day.
Combination insulins are taken twice daily before meals. They provide a short- or rapid-acting insulin for mealtime blood sugar control and an intermediate-acting insulin for the background insulin need throughout the day.
Older Insulin TypesThere are several different types of insulin that are no longer available, for various reasons. Because there was originally no way to make human insulin in a laboratory, early forms of insulin came from cows (bovine insulin) or pigs (porcine insulin). However, once recombinant DNA technology became available, human insulin largely replaced pork and bovine insulin. Now, there are no longer any pork or bovine insulins manufactured or sold in the United States.
Lente (an intermediate-acting insulin), ultralente (a long-acting insulin), and inhaled insulin (Exubera®) are all forms of insulin that have been discontinued due to low sales.