Ultra Long-Acting Insulin

Reviewed by: HU Medical Review Board | Last reviewed: August 2023

Ultra long-acting insulin is a treatment option for people with type 2 diabetes (T2D). It is used to control blood sugar. Ultra long-acting insulin starts to work a few hours after injection and stays active for up to 42 hours.1-3

Insulin is what helps the body store and use energy from glucose. People with T2D make insulin in their bodies, but they do not respond well to it. This is why they may need to take insulin as a treatment.1

An ultra long-acting insulin may be recommended when:3,4

  • Effects of other insulin treatments do not last a full day
  • Improved absorption is desired
  • Flexible dosing is desired

How does ultra long-acting insulin work?

Ultra long-acting insulin is different from other insulin types that work on rapid, short, intermediate, or long time frames. While it takes up to 6 to 12 hours to reach the maximum effect, it is released slowly and steadily over time. It does not peak and mimics the rate at which the pancreas would normally release insulin. This helps to keep your blood sugar levels controlled and steady over long periods of time.1,2,4

Ultra long-acting insulin is usually taken once a day. It must be injected into the fat layer under the skin to reach the bloodstream.2,3

Ultra long-acting insulin treatments are available in different doses. Your doctor will decide which is most helpful for you. Your doctor may also prescribe other T2D drugs in addition to an ultra long-acting insulin.2,4


Ultra long-acting insulin is sold under the brand names:3,5,6

  • Toujeo® (insulin glargine)
  • Tresiba® (insulin degludec)

What are the possible side effects?

Side effects can vary depending on the specific ultra long-acting insulin you are taking. People who take either Toujeo (insulin glargine) or Tresiba (insulin degludec) may experience:3,5,6

  • Low blood sugar
  • Discomfort or rash at the injection site
  • Itchy skin
  • A loss of fat from some areas of the body with fat gain at other areas (lipodystrophy)

Serious but uncommon allergic reactions may happen with both of these insulin treatments.5,6

These are not all the possible side effects of ultra long-acting insulin. Talk to your doctor about what to expect when taking ultra long-acting insulin. You also should call your doctor if you have any changes that concern you when taking an ultra long-acting insulin.

Other things to know

Toujeo (insulin glargine) can be used in adults and children as young as 6 years old. Tresiba (insulin degludec) can be used in adults and children as young as 1 year old.3,5,6

Before starting insulin treatment, let your doctor know if you:5,6

  • Plan to become pregnant
  • Are taking any new prescription or over-the-counter medicines

When taking insulin treatment let you doctor know if you:5,6

  • Feel short of breath
  • Gain a lot of weight quickly
  • Have swelling in your ankles or feet

Before beginning treatment for T2D, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.

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