What is insulin?

Insulin is a hormone made by the pancreas in your body. It controls the amount of glucose (sugar) in your blood. Insulin helps glucose move from your blood into your cells, where it can be used for energy.

How does insulin treat diabetes?

The 2 main types of diabetes are type 1 diabetes and type 2 diabetes.

In type 1 diabetes, your body stops making insulin or makes very little insulin.

In type 2 diabetes, your cells do not respond properly to insulin. This is known as ‘insulin resistance’. Eventually, your body stops making enough insulin.

Insulin injections are used to replace or ‘top up’ the insulin in your body.

Do I need to take insulin?

Most people with type 2 diabetes start by taking tablets to control their blood sugar levels. Over time, some people with type 2 diabetes need injected insulin.

All people with type 1 diabetes need injected insulin.

What types of insulin are available?

The insulin used to treat diabetes is made in a laboratory. It is made as close to natural human insulin as possible. It works in the same way to control your blood glucose levels.

You can't take insulin as tablets, because the digestive juices in your stomach would break down the insulin.

There are several different types of insulin available:

• Fast-acting insulin — starts to work in 5 to 20 minutes. Its effect peaks at about 30 minutes to 1 hour after the injection, and lasts for 3 to 5 hours. It’s important to eat right away after injecting fast-acting insulin to avoid hypoglycaemia (low blood sugar).
• Short-acting insulin — starts to work in about 30 to 60 minutes. Its effect peaks at 2 to 5 hours after the injection and lasts for 6 to 8 hours.
• Intermediate-acting insulin — starts to work about an hour and a half after you inject it. Its effect peaks at about 4 to 12 hours and lasts for 16 to 24 hours.
• Long-acting insulin — works for about 24 hours at a steady dose (with no peak).

Fast- and short-acting (bolus) insulins are taken with meals.

Longer-acting (basal) insulins are taken at regular times, regardless of mealtimes. They last all day, supplying the ‘background’ insulin your body needs to maintain a normal blood glucose level.

Combination injections, with short- and long-acting insulins, are also available.

Depending on the type of insulin and delivery device you use, you will probably need to inject insulin a few times a day.

Your doctor or diabetes educator will discuss your medical situation and lifestyle. They will recommend the best insulin regimen and delivery device for you.

How do I store insulin correctly?

Insulin must be stored correctly to work properly.

When stored in the fridge, insulin will last until its expiry date.

If kept at room temperature (below 25⁰C), it will last for one month. Do not use insulin that has been out of the fridge for more than one month.

Spare insulin should always be kept in the fridge. Use the door of the fridge so it doesn’t freeze. Never put insulin in the freezer.

How do I take insulin?

Insulin needs to be injected to work properly. There are a few different types of delivery devices available to inject insulin.

Your doctor or diabetes educator can advise you about how to take insulin using your device. It is important that you always follow this advice exactly.

Contact your diabetes educator if you:

• have forgotten or missed a dose of insulin
• are late taking your insulin
• have not taken enough insulin

What should I do if I take too much insulin?

Taking too much insulin or other diabetes medicines can cause your blood sugar level to drop too low. This is called hypoglycaemia (low blood sugar) or a ‘hypo’.

Hypoglycaemia can be serious if not addressed. If you think you have taken too much insulin, check your blood glucose level as soon as possible. Repeat this frequently.

If your blood glucose level is low, you will need to address this straight away with glucose. Read the healthdirect page on hypoglycaemia for how to do this.

What should I do if I miss a dose or take too little insulin?

Taking too little insulin can cause your blood glucose level to rise too high. This is called hyperglycaemia (high blood sugar).

Ask your diabetes healthcare team for a set of instructions on what to do if you forget your insulin.

If you have missed a dose of insulin, or have not taken enough insulin:

• Do not take the missed dose or extra insulin unless your diabetes educator or doctor advises you to do so.
• If you have a missed dose plan, follow those instructions.
• Drink plenty of sugar-free, non-alcoholic fluids such as water to stay well hydrated.
• Continue to monitor your blood glucose level regularly.
• If you find your blood glucose level stays high, you will need to address this.

What should I do if I run out of insulin?

It is a good idea to always keep at least one spare vial of insulin for emergencies. Remember to take your insulin with you when you go out.

If you run out of insulin:

• contact your doctor or diabetes educator for advice
• ask your pharmacist if they can give you an emergency supply (they may charge for this service)

What should I do if my insulin is expired?

All insulin has an expiry date printed on the packet. If this date has passed, do not use the insulin. Instead, return it to the pharmacy for safe disposal.

How do I safely dispose of ‘sharps’?

Sharps are medical devices that can go through your skin. These include syringes, pen needles, lancets (finger prickers) and insulin pump insertion needles.

It’s important to dispose of these safely, to prevent needlestick injuries and to protect people in the community. Do not dispose of sharps in household general waste bins.

Place used sharps in specially designed ‘sharps bins’. These are available from pharmacies. You can dispose of sharps bins at:

• hospitals
• pharmacies and some medical centres
• community sharps disposal bins provided by local councils

Resources and support

You can search for diabetes services near you, including diabetes educators and after-hours pharmacies using the Find a Health Service tool.

Visit Diabetes Australia for information and resources. You can also:

• call Diabetes Australia on 1800 177 055
• find resources for Aboriginal and Torres Strait Islander people
• get multicultural resources
• read about sharps disposal locations around Australia

The National Diabetes Services Scheme (NDSS) has a range of resources, support services and subsidised diabetes products. The NDSS website also has a range of diabetes resources in languages other than English.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.