Long Acting Insulin
One form of insulin is long acting insulin. If you have insulin glargine, insulin detemir, or insulin degludec then you have long acting insulin. If you’re not sure which type you have, look for the brand names Lantus, Levemir, Basaglar, Toujeo, or Tresiba.
Long acting insulin is made in a special way that allows it to hang around in your body for the whole day after injecting it. So, instead of injecting your insulin with every meal, you just inject it once every morning. Long acting insulin is usually called the “background” insulin, and you may still have to take another insulin product with your meals. The combination of both long acting and short acting insulin ensures that your body can handle anything throughout the day.
This graph below shows how long each different type of insulin will hang around in your body after equivalent injections. You can see that the long acting insulin lasts the whole day, but it doesn't have a very high activity. That's why we call it the "background" insulin. The short acting insulin doesn't last very long, but while it does work it has very high activity. That's why short acting insulin works so well before meals.