Injecting insulin for type 2 diabetes

Insulin is a hormone produced in the body by the pancreas (an organ found behind the stomach). When blood sugar (glucose) levels rise — for example, after a meal — insulin controls glucose levels in the body, by causing the liver, muscle and fat tissue to take up glucose from the blood. People with diabetes may not produce enough insulin, so insulin can be injected instead. The manufactured insulin does exactly the same job as your body’s own insulin would.

A person injecting insulin

Injecting insulin, using a needle and syringe, into the fat layer under the skin (subcutaneously) around the muscles of the stomach. Insulin can also be injected using a ‘pen’ device. Image:

Where do I inject insulin?

Insulin cannot be taken by mouth because it is destroyed by the digestive acids in the stomach. So it is injected under the skin (subcutaneously) into the fat layer, usually around the muscles of the stomach or into the leg. The abdominal wall (stomach muscles) is the best site for injections as insulin injected there is taken up by the body quickly and evenly and therefore starts to work more rapidly. The thigh, upper arm or buttock can also be used but insulin injected in these areas is absorbed into the system more slowly (unless the person is exercising).

While many people worry about injecting insulin, most find the injections are not painful. Insulin should be injected into different places on the body (but not the arms) to prevent lipodystrophy (a lump or small dent in the skin that can form when injections are made regularly in the same place).

How do I inject insulin?

Insulin comes in a number of types and forms. Some types of insulin come in more than one different type of container:

  • as a cartridge that is used with a pen injection device
  • in a pre-filled disposable pen device
  • in a vial — so the insulin is injected using a disposable syringe.

This means that with some types of insulin, you will have a choice of different injection devices. The choice of device will depend on the type of insulin that is recommended for you, advice from your health professional, and your personal preference. A health professional can also provide advice about:

  • how to use your injection device
  • the most suitable length and width of needle for you
  • how, when and where to inject your insulin
  • how long your insulin takes to work and how long it works for
  • side effects of insulin
  • how to dispose of your needles, and used pens safely.

A syringe pen with a cartridge containing insulin.A pack of insulin cartridges that can be used with a syringe pen.

Many types of insulin come in cartridge form. A health professional can provide advice about how to inject insulin and the injection devices available.

A pre-filled disposable insulin injecting pen.

Pre-filled disposable injecting pens. Your health professional can provide advice about the most suitable insulin and injection device for you.

A disposable syringe being filled with insulin from a vial.

A new syringe and needle will be needed for each dose administered, and these must be disposed of safely after use. A health professional can provide advice about how to inject insulin and the injection devices available.

How many injections will I need?

People with type 2 diabetes may only need to inject insulin once or twice a day depending on the type of insulin, and their glucose levels. For some people, a single injection of insulin is enough. It may take a little time to find the right combination and timing of injections.

If you have type 1 diabetes, you may need up to four injections of insulin a day depending on the type of insulin you are using and your glucose levels. See our type 1 diabetes hub for more information.

For people who need frequent insulin injections, an insulin pump can be a convenient alternative. To find out more, read our information about insulin pumps.