Types of Insulin

There are three main groups of insulins: Fast-acting, Intermediate-acting and Long-acting insulin.

Fast-acting insulin:
Is absorbed quickly from your fat tissue (subcutaneous) into the bloodstream.
Is used to control the blood sugar during meals and snacks and to correct high blood sugars

Includes:

Rapid Acting Insulin Analogs (Insulin Aspart, insulin Lyspro, Insulin Glulisine) which have an onset of action of 5 to 15 minutes, peak effect in 1 to 2 hours and duration of action that lasts 4-6 hours. With all doses, large and small, the onset of action and the time to peak effect is similar, The duration of insulin action is, however, affected by the dose – so a few units may last 4 hours or less, while 25 or 30 units may last 5 to 6 hours. As a general rule, assume that these insulins have duration of action of 4 hours.

Regular Human Insulin which has an onset of action of 1/2 hour to 1 hour, peak effect in 2 to 4 hours, and duration of action of 6 to 8 hours. The larger the dose of regular the faster the onset of action, but the longer the time to peak effect and the longer the duration of the effect.