Different Types of Insulin

Where Insulin Comes From

Almost all of the insulin sold in the United States today is what is known as "human insulin." Developed by scientists, this laboratory-created insulin is made by DNA recombinant technology and is very similar, really identical, to insulin from a human pancreas. It's available in varieties that are designed to start working within just a few minutes or last for many hours, giving insulin users a lot of control over their blood sugar levels. (Before the introduction of human insulins, people used insulin from beef and pork sources.)

Insulin can't be taken as a pill or capsule because the digestive juices in the stomach ruin its effectiveness. Oral insulin pills might be a reality someday, but right now the only way to take insulin is by injecting it directly into the layer of fat just below the skin. Most people inject insulin with a syringe or insulin pen, although other methods are available.

Basal and Bolus Insulins

The pancreas naturally secretes insulin in two different ways:

  • A slow, continuous trickle of insulin that stays at a low level in the blood at all times (known as "basal insulin").
  • Large bursts of insulin that are released when your blood sugar rises, typically after meals (known as "bolus insulin").

While people with type 1 diabetes need a treatment program that gives them both basal and bolus insulin, the treatment for people with type 2 varies and usually changes over time:

  • Some people with type 2 diabetes only need basal insulin injections (often just a single shot at bedtime) because their pancreas can still provide the extra insulin needed for meals.

  • Some people with type 2 diabetes need both basal and bolus insulin.

  • Many people with type 2 diabetes don't need any insulin injections.

Injections of rapid-acting and short-acting insulins provide the bolus insulin supply needed after meals. Conversely, injections of intermediate-acting and long-acting insulin mimic the body's natural basal supply.


The BD Diabetes Learning Center describes the causes of diabetes, its symptoms, and diabetes complications such as retinopathy and neuropathy. This site contains detailed information about blood glucose monitoring, insulin injection and safe sharps disposal. Interactive quizzes, educational literature downloads and animated demonstrations help to teach diabetes care skills.

Important Note: The content of this website is not intended to be a substitute for professional medical advice, diagnosis or treatment. Do not disregard your doctor's advice or delay in seeking it because of something you have read in this website.

Unless otherwise noted, BD, BD logo and all other trademarks are property of Becton Dickinson and Company. © 2017 BD