Information for the public

Using insulin

All adults with type 1 diabetes need to use insulin, because their body does not make it. Insulin cannot be taken as a tablet and has to be injected.

Which insulins?

There are several different types of insulin treatment, which vary in both the insulins used and the number of injections. You should usually be offered 2 insulins that act in different ways:

  • a 'background' (also known as a 'basal' or 'long‑acting') insulin that is ideally injected twice a day and

  • a 'quick‑acting' (also known as a 'bolus' or 'rapid‑acting') insulin that is injected before each meal, to deal with the rise in blood glucose from eating.

A number of options are possible depending on what suits you. Your diabetes care team will talk with you about this, so that you can agree what is best for you.

Your care team should also give you clear advice about adjusting your insulin doses, in response to your blood glucose test results and also for when you are ill (sick-day rules).

Some people may be offered an insulin pump if:

  • they are having problems with severe hypos or

  • their HbA1c levels are still too high even though they have been careful to take their insulin correctly.

Biosimilar insulins

Your care team may talk to you about changing to a 'biosimilar' version of an insulin you are taking. A biosimilar is a biological copy of an existing insulin. Biosimilar insulins are cheaper and work in exactly the same way as the original insulin. However, you do not have to switch to a biosimilar if you are happy with your current insulin. Switching is a decision that needs to be made between you and your diabetes care team.


If you are overweight and you want to keep your insulin dose as low as possible, you may be offered a medicine (tablet) called metformin as well as insulin.

Injecting insulin

Insulin is commonly injected using a device called an 'insulin pen'. Your diabetes care team should help you choose the type of device and needles that suit you, and offer you different needles to try if your skin gets sore or irritated.

Your skin can get lumpy if you keep injecting in the same place, so you should use different areas of your body (stomach, thighs, bottom, upper arms) and different spots in these areas. Your care team will check your skin at your annual review, and more often if needed.

You should be given a special secure container (called a 'sharps bin') for used needles, lancets (from finger pricking) and any other sharps. You should also be told how to get rid of these containers when they are full and how to get new ones.

Questions to ask about insulin

  • Please explain about the differences between the different insulins

  • Why might I need to change my insulin dose if I'm ill?

  • Can I take metformin as well as insulin?

  • How often do I need to inject insulin? What are the best times to do this?

  • Where should I inject?

  • What different types of insulin device and needles are available?

  • Information Standard