What is short acting insulin?

It is a type of insulin analog that works very fast to reduce high levels of blood sugar. As a result, short-acting insulin is normally prescribed together with long-acting insulin. Compared to rapid-acting insulin, short-acting insulin does not work as fast in lowering the levels of blood glucose in diabetic people. Hence, short-acting insulin may be prescribed to certain diabetic patients. Short-acting insulin comes in human or animal insulin form that is normally injected subcutaneously using a syringe. It is recommended you take short acting insulin before you eat. Your doctor will tell you how long you should stay before you take a dose of short acting insulin.

Short acting insulin peak times, onset and duration

Onset refers to how fast short-acting insulin works in the body to lower levels of blood glucose after injection. Peak time is the period when short-acting insulin is most effective in reducing the levels of blood sugar. Duration refers to how long short-acting insulin works in the body to reduce the levels of blood glucose. Short acting insulin has an onset of 30 to 60 minutes, peak time of about 2 hours and duration of up to 8 hours.

Brand names


Actrapid is a prescription fast-acting insulin drug that is technically classified as a short-acting insulin. This insulin is produced by a company called Novo Nordisk and comes in prefilled vials. Actrapid is normally taken before a meal and may be prescribed together with long- or intermediate-acting insulin. Actrapid is usually administered subcutaneously but it may also be injected intravenously by a nurse or doctor.


Novolin is the brand name of insulin isophane that is usually prescribed together with exercise and diet program to control levels of blood sugar in diabetic patients. This insulin medication can be used by people with type 1 and type 2 diabetes. Your doctor will show you how to safely administer this medication at home.


Velosulin is a fast acting animal insulin that is made by Novo Nordisk. Velosulin, which is also known as regular insulin, works the same as human insulin. When you inject insulin regular, it helps the body cells absorb sugar from the bloodstream.

Side effects

The most common side effect of short-acting insulin is hypoglycemia. If you are taking short-acting insulin, it is important you watch out for low blood glucose symptoms like

  • hunger
  • fast heartbeat
  • shakiness
  • blurred vision
  • dizziness
  • confusion
  • slurred speech

Other side effects include the following:

  • Low blood potassium
  • Severe allergic reaction
  • Heart failure
  • Swelling in feet and hands

Disclaimer: Please note that the contents of this community article are strictly for informational purposes and should not be considered as medical advice. This article, and other community articles, are not written or reviewed for medical validity by Canadian Insulin or its staff. All views and opinions expressed by the contributing authors are not endorsed by Canadian Insulin. Always consult a medical professional for medical advice, diagnosis, and treatment.