All About Insulin

What is insulin? 

Insulin is a hormone produced by the pancreas that helps your body use glucose (sugar) from the food you eat for energy or store it for later use. It helps regulate your blood sugar levels and prevents them from becoming too high (hyperglycaemia) or too low (hypoglycaemia). 

People with diabetes may need insulin injections when their bodies do not produce enough insulin or cannot use it effectively.

What are the different types of insulin? 

Insulin is available in different types, which vary in how quickly they start working and how long their effects last.

• Rapid-acting insulin: Examples include insulin lispro.

• Short-acting insulin: An example is regular insulin.

• Intermediate-acting insulin: An example is NPH insulin.

• Long-acting insulin: An example is insulin glargine.

• Premixed insulin: Combines two types of insulin in a fixed proportion, such as 70/30 formulations.

The type of insulin prescribed depends on your individual needs and treatment plan. Always follow your healthcare provider’s instructions.

How can you store insulin? 

• Open insulin vials can be stored between 2°C and 30°C for a duration of 28 days. 

• Unopened insulin vials stored in the refrigerator can be used until the expiry date. 

• Insulin pens should be stored at room temperature. 

What factors affect insulin dosage? 

Your insulin dose is individualised and may depend on several factors, including:

1. Blood glucose levels

2. Food intake and carbohydrate consumption

3. Physical activity level

4. Age

5. Body weight

6. Insulin resistance

7. Illness, stress and other medications

Types of insulin syringes

Insulin syringes are available in different sizes. A U-100 insulin syringe is designed for insulin with a concentration of 100 units per millilitre (mL).

Always use a syringe that matches your insulin concentration and prescribed dose. Ask your healthcare provider or pharmacist to demonstrate the correct syringe and measurement technique.

How to prepare an insulin injection using a vial and syringe

Supplies required

• Prescribed insulin vial or vials

• Appropriate insulin syringe

• Alcohol swab, if required

• Approved sharps disposal container

Method 1: Preparing a Single Vial (Pre-mixed or NPH Insulin)

1. Wash your hands thoroughly with soap and water.

2. Gently roll the cloudy/milky insulin vial between your palms to mix it. Do not shake, as this creates air bubbles.

3. Wipe the top of the vial with an alcohol swab and let it dry.

4. Pull the syringe plunger down, drawing air into the syringe equal to your required insulin dose.

5. Push the needle through the rubber top of the vial and inject the air into the bottle.

6. Leave the needle in, turn the vial upside down, and pull the plunger down to draw your required dose.

7. Tap the syringe gently to force any air bubbles to the top, and push them back into the vial. Remove the needle.

Method 2: Mixing Two Vials

1. Wash your hands and gently roll the cloudy vial to mix. Wipe both vials with an alcohol swab.

2. Pull air into the syringe equal to the cloudy insulin dose. Inject this air into the cloudy vial, then remove the needle without drawing insulin.

3. Pull air into the syringe equal to the clear insulin dose. Inject this air into the clear vial.

4. Keep the needle in the clear vial, turn it upside down, and draw your clear insulin dose. Remove the needle.

5. Insert the needle into the cloudy vial, turn it upside down, and carefully draw your cloudy insulin dose. Be precise, as you cannot push mixed insulin back into the vial.

Administering your insulin

Common insulin injection sites

Insulin is injected into the fatty tissue just beneath the skin. Common injection sites include:

• Upper arms: The fatty tissue at the back of the upper arm.

• Abdomen: The fatty tissue of the abdomen, avoiding the area immediately around the navel.

• Thighs: The fatty tissue at the front or outer part of the thighs.

How to administer insulin using a syringe

1. Clean the chosen injection site with water or an alcohol swab and let it dry completely.

2. Gently pinch a 1-to-2-inch fold of skin.

3. Insert the needle quickly and smoothly at a 90° angle (a 45° angle may be recommended for children or very thin individuals).

4. Push the plunger down completely to inject the insulin.

5. Keep the needle in the skin for 10 seconds to ensure the full dose is delivered.

6. Pull the needle straight out. Release the pinched skin.

7. Gently press a clean swab over the site if there is minor bleeding. Do not rub or massage the area.

8. Dispose of the syringe immediately in your sharps container. Do not recap the needle.

How to use a prefilled insulin pen

Supplies required

• Prescribed insulin pen

• Compatible pen needle

• Alcohol swab, if needed

• Approved sharps disposal container

Procedure

1. Wash your hands and verify you have the correct insulin pen.

2. Remove the pen cap and wipe the rubber seal with an alcohol swab.

3. Screw a new, sterile needle tightly onto the pen. Remove both the outer and inner needle caps.

4. Prime the pen: Dial to 2 units, point the needle up, and push the button until a drop of insulin appears. This clears air from the needle.

5. Dial the pen to your prescribed dose.

6. Clean the injection site, let it dry, and gently pinch the skin.

7. Insert the needle straight into the skin at a 90° angle.

8. Push the injection button down completely.

9. Continue holding the button down and slowly count to 10 before removing the needle from your skin.

10. Carefully unscrew the used needle and dispose of it in a sharps container. Replace the pen cap.