How Do Short-Acting Insulins Work?

Reviewed on 1/10/2022


Short-acting insulins are a class of drugs used to control high blood sugar in people with type 1 (T1DM) and type 2 diabetes mellitus (T2DM) along with a proper diet and exercise. T1DM or insulin-dependent diabetes is an autoimmune condition in which the body does not produce insulin and therefore cannot control the amount of sugar in the blood. However, T2DM is a slowly progressive metabolic disorder caused by a combination of genetic and lifestyle factors that promote chronically elevated blood sugar levels. Proper control of diabetes may also reduce the risk for heart attack or stroke (loss of blood flow to part of the brain).

Short-acting insulin, also known as regular or human insulin, takes 30 minutes to start working and reaches a peak in two to four hours with its effects lasting for six to eight hours. They are often recommended along with a healthy diet, regular exercise, and other insulin products or oral diabetic medications.

Insulin is a peptide hormone produced by the beta cells of the pancreas to help metabolize food and use it for energy throughout the body. Insulin is released from the pancreas following a meal to promote the uptake of glucose (a type of sugar found in many carbohydrates) from the blood into internal organs and tissues such as the liver, fat cells, and skeletal muscles. It allows the body to use glucose for energy; helps in storing glucose in the liver, fat, and muscles; and regulates body’s metabolism of carbohydrates, fats, and proteins.

Short-acting insulins are administered subcutaneously (under the skin) in the stomach area, thighs, buttocks, or back of the upper arm typically 30 minutes before meals.

Short-acting insulins work in the following ways:

They are man-made product similar to human insulin and often used along with a long-acting insulin product.

They work by replacing the insulin that is normally produced by the body and help in the absorption of sugar from the blood into other body tissues for energy.

In addition, they prevent the liver from producing more sugar.


Short-acting insulins are indicated to improve glycemic control in patients with T1DM and T2DM along with a proper diet and exercise.


Some of the common side effects include:

  • Injection site reaction (pain, redness, and irritation)
  • Weakness
  • Diarrhea
  • Headache
  • Tiredness
  • Nausea
  • Sore throat
  • Other rare side effects include:
  • Weight gain
  • Hypokalemia (low blood potassium level)
  • Muscle cramps
  • Dizziness (feeling faint, weak, or unsteady)
  • Swelling of the arms, hands, feet, ankles, or lower legs
  • Confusion
  • Hypoglycemia (low blood sugar level)
  • Sudden sweating
  • Fast heartbeat
  • Blurred vision
  • Tingling in hands/feet

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.


Generic and brand names of short-acting insulins include:

References condition.htm#what_are_side_effects_associated_with_using_insulin

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