Insulin Injection Technique: 7 Common Mistakes and How to Avoid Them
For individuals with diabetes who rely on insulin, proper injection technique is as important as the medication itself. Injecting insulin the wrong way can lead to poor blood sugar control, pain, bruising, and even skin complications like lipohypertrophy (lumps under the skin). Fortunately, these issues can be prevented with correct guidance.
Here’s a guide to the most common insulin injection mistakes and how to avoid them.
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Using the Same Injection Site Repeatedly
Mistake: Injecting insulin into the same spot daily (e.g., the same side of the abdomen)
Why it’s harmful: Repeated injections in one area can lead to lipohypertrophy, which reduces insulin absorption.
Solution: Rotate injection sites. Use different quadrants of the abdomen, thighs, arms, or buttocks. Rotate within each area in a circular pattern.
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Not Changing the Needle Each Time
Mistake: Reusing the same needle multiple times
Why it’s harmful: Needles become dull after a single use, causing pain, bruising, and infection risk.
Solution: Always use a new needle for each injection, even if you are using a pen device.
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Injecting into Muscle Instead of Fat
Mistake: Injecting too deeply, especially in lean individuals
Why it’s harmful: Insulin is meant to be injected into subcutaneous fat, not muscle. Muscle absorbs insulin faster, leading to sudden drops in blood sugar.
Solution: Use the correct needle length (4–6 mm is ideal for most people). If you are thin, lift the skin gently before injecting.
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Not Warming Insulin Before Use
Mistake: Injecting cold insulin straight from the fridge
Why it’s harmful: Cold insulin may cause more discomfort during injection and affect absorption.
Solution: Take insulin out of the fridge 30 minutes before use (if it’s a new vial). Once opened, insulin pens can be stored at room temperature.
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Incorrect Timing with Meals
Mistake: Taking rapid-acting insulin too long after meals
Why it’s harmful: It may not match the blood sugar spike after eating, causing poor control.
Solution: Take rapid-acting insulin 10–15 minutes before meals, unless otherwise advised by your doctor.
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Improper Storage of Insulin
Mistake: Exposing insulin to extreme temperatures
Why it’s harmful: Heat or freezing can damage insulin, making it ineffective.
Solution: Store unopened insulin in the fridge (2–8°C), but don’t freeze it. Opened vials or pens can be stored at room temperature (below 25°C) for up to 28 days.
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Skipping Site Inspection
Mistake: Injecting into scarred, lumpy or bruised skin
Why it’s harmful: Absorption may be unpredictable, leading to highs or lows in blood sugar.
Solution: Inspect your skin regularly and avoid damaged or lumpy areas.
Final Tip
Proper technique ensures insulin is absorbed correctly, keeping your blood glucose levels within target range. If you are unsure about your method, ask a diabetes educator or nurse to demonstrate.
