Does the injection site affect how well insulin works?

Preparation

• Make sure your hands are clean before the injection.
• Wipe the rubber stopper of the vial with an alcohol swab.
• If you see air left in the syringe while drawing up insulin, expel it.
• Insulin should be at room temperature when injected – do not heat it.
• Short-acting insulin should be clear: do not use insulin that is cloudy, has sediment or looks suspicious, or that is past its expiry date. Do not buy insulin from random people.

How to inject

Insulin must be injected into the fat layer under the skin – injecting it into muscle is wrong.

1. Pinch up a fold of skin with your fingers – this keeps the insulin from reaching the muscle layer.
2. Insert the needle at a 90° or 45° angle.
3. Wait 7–10 seconds after injecting, then withdraw the needle and release the skin fold.
4. Press on the injection site without massaging it. Applying heat to the injection site is also wrong.
5. Inject insulin only at the times prescribed by your doctor.

Where to inject

Another important point is the injection site: insulin is absorbed at different speeds from different parts of the body, so its effect depends greatly on where it is injected.

• front of the abdomen – fastest absorption;
• front and outer thigh and outer upper arm – medium absorption;
• outer buttock – slowest absorption.

Remember to rotate sites

Injecting the same type of insulin into the same area every time is not right – otherwise your blood sugar may swing up and down.

Each time, insert the needle at least 2 cm away from the previous injection site.

If injection sites are not rotated, dents (lipoatrophy) or hard lumps (lipohypertrophy) can form in the fat under the skin. Injecting into the same area also causes bruising.

Do not reuse needles

Insulin pen needles are single-use and should be changed with every injection. Reusing them can lead to the following:

• insulin can crystallise inside the needle and block it;
• the needle loses its lubricating coating and the injection becomes painful;
• the needle tip becomes blunt, causing both pain and bruising;
• with excessive use the needle tip can break off and leave metal particles under the skin.

If bruises appear

A bruise forms when the needle touches a small blood vessel under the skin. Such bruises disappear completely after a while. To prevent them, you can apply an ice pack for 30–60 seconds before the injection, try not to inject too close to the navel and use a new needle every time. If you take blood-thinning medicines, bear in mind that your risk of bruising is higher.

How to store insulin

When insulin is kept at temperatures above 25 °C, its composition changes and it starts to lose its strength. This can lead to an unexplained rise in blood sugar and even a diabetic coma.

• Keep unopened insulin in the fridge at 2–8 °C, for example in the fridge door.
• Insulin that is in use can be kept at 15–25 °C for up to 28–30 days.
• Never freeze insulin – frozen insulin is ineffective.
• Do not leave insulin in direct sunlight or in a car – in a hot car it can become ineffective within a few hours.
• Use a thermal (insulated) bag when travelling.
• Do not shake insulin hard or fast.