Easy-to-read medicine information about insulin – what it is, how to use insulin safely and possible side effects.
Insulin in our body is made by our pancreas so if the insulin-producing cells in our pancreas are damaged, (such as in type 1 diabetes and over time in type 2 diabetes) then we need to replace this insulin to help our bodies function well.
Insulin cannot be taken by mouth as a tablet because it is inactivated by our digestive enzymes.
Insulin needs to be taken as an injection, just under the skin so it can be absorbed into the bloodstream and travel around the body to help glucose get into our cells and give us the energy we need for daily life.
Types of insulin
There are different brands of insulin available in New Zealand and these are grouped by the time it takes for the insulin to work.
Rapid acting insulin
Usually works straight away, so it is injected just before or with food. Its effect lasts 1 to 2 hours.
Short acting insulin
Usually works within 15 to 20 minutes, so inject each dose 15 to 20 minutes before you eat. Its effect lasts 3 to 4 hours.
Intermediate and long acting insulin
Usually works after about 1 hour. Its effect lasts all day and may be injected once or twice a day.
Levemir (not subsidized in New Zealand)
These insulins are a mixture of short and intermediate acting insulins. These may be injected twice a day.
NovoMix 30 FlexPen
Humalog Mix 25
Humalog Mix 50
Your doctor or nurse will work with you to find the best insulin to meet your needs. This can be made up of a rapid acting insulin and an intermediate or long acting insulin, or it can be insulin and tablets.
How to use insulin
The timing of your insulin in relation to food and exercise is important. Your doctor or nurse will advise you when it is best to use your insulin.
It is best to avoid hot showers or baths within 30 minutes of an insulin dose.
Your doctor or nurse will advise what to do if you miss a dose of insulin.
Drinking alcohol can affect blood glucose and the dose of insulin may need to be changed. Avoid or limit alcohol intake.
If you are unwell and not eating as you usually do, your insulin dose may need to be changed. Contact your doctor or nurse for advice.
Insulin should be injected into the fatty tissue under the skin. The abdomen or tummy area, about 5 cm away from your belly button, is usually a good place. It is easy to reach and insulin absorbs well from this area.
Other areas such as the buttocks, thigh or outer arm are usually not preferred because they are harder to reach, insulin is absorbed slower and absorption may be affected by exercise.
Move injection sites so that the skin does not become lumpy. Lumpy skin can affect how your body absorbs insulin. You can move from one side of your abdomen to the other side each time.
Unopened insulin can be stored in the fridge until it is used.
Do not store insulin in the freezer.
Once opened, insulin vials, cartridges or pre-filled pens can be kept at room temperature but must be discarded after 28 days.
Side effects when using insulin
Sometimes insulin may lower your blood sugar too much – called hypoglycaemia. This may cause you to feel weak, faint, dizzy, drowsy or irritable. You may get a headache, tremor (shakes) or blurred vision. If this occurs, drink something sweet such as a small glass of sweetened soft drink, or fruit juice, or eat something sweet such as lollies. Make sure your family and friends know what to do too. Tell your doctor or nurse if this happens a lot. Your dose of insulin may need to be changed.
Pain or redness at the injection site – change the injection site and contact your doctor or nurse if the pain or redness continues.
Insulin interacts with some other medications and herbal supplements so check with your doctor or pharmacist.
It is important to inject insulin correctly. Ask your diabetes nurse, pharmacist or doctor for advice.
For insulin pens:
Wash your hands with soap and water before injecting.
Use a new needle for every injection to minimise pain. Reusing needles can lead to bruising, bleeding and infection.
Dial the number of units you are going to inject by turning the dose selector knob.
Inject insulin into the fatty tissue just under the skin, in the abdomen or tummy area, about 5 cm away from your belly button. Read more about injection sites below.
Hold the pen in your hand with your thumb or finger on the dose selector knob at the end of the pen.
If you are using an 8 mm (or longer) needle, pinch up your skin on your stomach then slide the needle into the skin fold at a 90º angle. If your needle is less than 8 mm long, don't pinch up your skin.
Push the dose selector to inject the dose, relatively slowly, as far as it will go. The dose window should read zero.
Leave the needle in for 6 seconds.
Continue to push in the dose selector knob while you remove the needle.
Insulin should be injected into the fatty tissue under the skin. The abdomen or tummy area, about 5 cm away from your belly button, is usually a good place. It is easy to reach and insulin absorbs well from this site.
Other areas such as the buttocks, thigh or outer arm are usually not preferred because they are harder to reach, insulin absorbs slower and absorption may be affected by exercise.
Do not inject your dose into the muscle, this can be painful and affects the absorption of insulin in the body.
If you think you are injecting into the muscle, talk to your diabetes nurse, pharmacist or doctor.
Move injection sites so that the skin at the site of injection does not become lumpy. Lumpy skin can affect how your body absorbs insulin. You can move from one side of your abdomen to the other side each time.
Do not inject insulin into any scar tissue.
Tips to minimise pain when injecting insulin
Injecting insulin can cause discomfort, but it should not be painful. Here are a few tips to minimise pain when injecting:
Make sure your stomach muscles are relaxed.
Use insulin and a needle at room temperature.
Push the needle in quickly and hold for about 10 seconds before removing the needle.
Try not to wiggle the needle as you’re injecting or removing it.
Always use a new needle for every injection.
Move the site of injection – do not inject into the same site you last used. This will help avoid scarring and reduce pain.
The following links provide more information on injecting insulin. Be aware that websites from other countries may have information that differs from New Zealand recommendations.
In New Zealand insulin is available as 10 mL vials and 3 mL cartridges.
Insulin from the 10 mL vial is injected using a syringe with a needle.
Insulin from the 3mL cartridge are given using an insulin pen. There are 2 types of insulin pens:
Reusable pen which allows you to replace the insulin cartridge when it's empty or expired – The cartridge can be removed from the pen, thrown away and a new cartridge is fitted into the same pen.
Disposable pen in which a cartridge is pre-fitted into the pen and cannot be removed. When the insulin runs out, the entire pen is thrown away and a new pen is required.
Syringes & needles
There are 3 different sized syringes available in New Zealand: 0.3mL, 0.5 mL and 1 mL.
The strength of all insulins in New Zealand is 100 units/mL, so a 0.3 mL syringe has doses of up to 30 units. A bigger syringe is used for larger doses.
People who mix insulins in the syringe may prefer a larger syringe (0.5 mL or 1 mL) to allow for ease of mixing.
Syringes have attached to them a variety of different sized needles. Needle sizes are measured by their thinness (gauge) and their length (in mm); for example 31 gauge x 8 mm.
The higher the gauge, the thinner the needle; for example, a 31 gauge needle is thinner than a 28 gauge needle.
People who use syringes more than once may prefer a stronger (lower gauge number) needle. If the syringe is being used for a young child the finer, shorter (31 gauge, 8 mm) needle may be preferred.
Syringe sizes available in New Zealand¹
0.3 mL with 29 gauge x 12.7 mm needle
0.3 mL with 30 gauge x 8 mm needle
0.3 mL with 31 gauge x 8 mm needle
0.5 mL with 29 gauge x 12.7 mm needle
0.5 mL with 31 gauge x 8 mm needle
1 mL with 27 gauge x 12.7 mm needle
1 mL with 29 gauge x 12.7 mm needle
1 mL with 31 gauge x 8 mm needle.
If you are unsure of which syringe and needle size is best for you, talk to your diabetes nurse, pharmacist or doctor.
In New Zealand, you can have 100 subsidised syringes on a prescription if insulin is also on the prescription or the prescription is endorsed as being for a patient using insulin. Your doctor can write more than one prescription. Read more about syringes
Insulin pens are similar in size and shape to a writing pen. Pens make measuring and injecting your insulin easier and are easy to carry around. Insulin pens are not pre-fitted with needles. A suitably sized needle has to be attached to the pen. There are 2 types of pen devices available in New Zealand: reusable and disposable.
Reusable pens allow you to replace the insulin cartridge. When the cartridge runs out or expires, it is removed from the pen, thrown away and a new cartridge is fitted into the same pen.
In New Zealand, insulin is supplied by Novo Nordisk, Eli Lilly and Sanofi-Aventis. It is important to use the correct insulin brand in the correct pen. For example, Lilly pen will use Lilly insulin cartridges, a Novo-Nordisk pen will use Novo-Nordisk insulin cartridges, etc. Reusable pens are available at no cost from Diabetes Clinics and pharmacies.
These pens have an insulin cartridge pre-fitted into the pen that cannot be removed. When the insulin runs out, the pen is thrown away and a new pen is required.
Insulin pens are not pre-fitted with needles. A suitably sized needle has to be attached to the pen. Needle sizes are measured by their thinness (gauge) and their length (in mm); for example 31 gauge x 8 mm. The higher the gauge, the thinner the needle; for example, a 31 gauge needle is thinner than a 28 gauge needle.
Needle sizes available in New Zealand²
29 gauge x 12.7 mm
31 gauge x 5 mm
31 gauge x 6 mm
31 gauge x 8 mm
32 gauge x 4 mm
28 gauge x 12 mm
30 gauge x 8 mm.
Which device: syringe or pen?
The decision to use syringes or pens is a personal one. Here are some points to think about:
Insulin pens are easy to carry around, and make measuring and injecting your insulin easier. Injections can be administered discretely. Most pens hold 300 units of insulin and allow delivery of up to 60 to 80 units at a time. Most insulins are available as pens.
Syringes hold up to 100 units. They may be best if you use mixed insulins or if you're giving insulin to a child.
Short and rapid acting insulins can also be given by a portable insulin pump. This delivers continuous insulin and can be activated to give extra insulin at meal times. These pumps can be useful for people who have hypoglycaemia often, or if their levels are difficult to control. There are certain criteria for funding, and many options available. For more information, see sub-cutaneous insulin infusions (insulin pumps), Ministry of Health, NZ.