Expert-reviewed by Ashwini S.Kanade, Registered Dietician and Certified Diabetes Educator with 17 years of experience
Insulin injections are a part and parcel of life for many people with diabetes. It is thus extremely important to ensure that insulin is taken correctly, to avoid any complications that may arise from the incorrect administration.
Dr Fred Williams, who is the Consultant Endocrinologist at Columbia Asia Hospital in Whitefield, Bangalore, shared with us a list of common insulin mistakes that should be avoided and how to avoid them.
1. Sharing your insulin pen:
This increases the risk of infection with bloodborne pathogens, such as hepatitis or HIV. If you are using a new needle every time, an insulin pen can be used multiple times. But do note that it is unsafe to share the same pen. According to the warning of the American Diabetes Association, blood and skin cells can be sucked into the insulin cartridge during a shot.  Hence, sharing a pen could easily expose you to infections. Make sure that every member of the household who uses insulin has their own pen.
2. Storing insulin incorrectly:
If insulin is exposed to extreme heat or cold, its ability to control blood sugar decreases. The longer the exposure, the less effective it becomes. These are the ideal conditions for storage:
- Unopened insulin should be stored in the refrigerator (set between 2°C and 7°C).
- An opened vial can be stored at room temperature or in the refrigerator for up to 28 days.
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3. Injecting insulin incorrectly:
The insulin should be injected right below the skin, in the fatty tissue area. Popular injection sites include the abdomen (staying two fingers or a few inches away from the belly button), outer thighs, hips, upper buttocks, lower back, and backs of the arms.  If insulin gets injected deeper into your muscle, it is more painful and it will also get absorbed too quickly into your body. All of which can lead to low blood glucose levels.
Here is the right way of injecting yourself with insulin:
- Start by gathering all the supplies.
- Wash your hands thoroughly with soap and water.
- Take a look at the insulin and double check the label for the correct product.
- Fill the syringe with the required dose. Make sure to not put more than one type of insulin in a single syringe.
- Administer the injection into the fat layer just under the surface of the skin.
- While injecting the dose, push the needle all the way into the skin and slowly push the syringe to deliver the dose. Ensure the plunger is completely depressed. Hold needle in place for 10 sec.
- After you are done, the needle and the syringe should be disposed of into the sharps container carefully.
4. Injecting too much insulin:
Having too much insulin in the blood can lead to too little glucose. If blood sugar levels fall too low, the body no longer has enough fuel to carry out its regular functions. In hypoglycemia (very low sugar), the body becomes so starved for fuel that it begins to shut down. If someone has diabetes and uses insulin to help control their blood sugar, they can end up with excess amounts of insulin in the blood if they inject too much insulin or miss a meal after injecting insulin.
5. Not checking the expiration date:
After the passing of the recommended expiration date, there is an increased possibility that the insulin is no longer sterile and effective. Even though an expiration date is stamped on each vial of insulin, a loss of potency might occur after the bottle has been in use for more than a month, especially if it was stored at room temperature. 
- Melissa K. Schaefer, MD, Rachel A. Kossover, MPH, RD, and Joseph F. Perz, DRPH. Sharing Insulin Pens: Are You Putting Patients at Risk? Published by American Diabetes Association at Diabetes Care. 2013;36(11):e188-e189. doi:10.2337/dc13-1522. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3816894/
- American Association of Diabetes Educators, Information Leaflet; Retrieved on 20th December 2017; Link: https://www.diabeteseducator.org/docs/default-source/legacy-docs/_resources/pdf/general/Insulin_Injection_Pro_Tips_AADE.pdf