Single use only

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Insulin injection - single use only

Why should I use a new pen needle each time I inject?

Pen needles are designed to deliver an insulin dose just once. Like all medical sharps, they are single-use products for good reason.

The reuse of needles has negative consequences. Don’t take any risks! Here you find details on why it is important to use a pen needle only once. 

Avoid pain and lipos

Avoid pain and lipos

A pen needle is a sterile, very precise medical device – for single use only. If you reuse it, the pen needle is no longer sterile, the fine silicone finish has worn off and the tip becomes blunt.

The consequences of multiple use:

  1. The needle is no longer sharp, so there is more pain if you inject again.
  2. The risk of lipohypertrophies (short: lipos) forming is higher.
  3. The possibility of the needle bending or breaking off increases.(3)

Receive the full dose

Receive the full dose

Leaving the needle on the pen and injecting yourself again leads to a higher risk of incorrect dosing.

Reason one: blockages

Tissue residue or crystallized insulin from the previous injection may block the needle. Thus, a correct insulin dose cannot be guaranteed anymore.

Reason two: air in the cartridge

Liquids are generally temperature sensitive: They expand when warmed and shrink when cooled down. When the liquid in the cartridge shrinks with the needle still attached, air is drawn inside. As a consequence, you either inject air with the insulin or the air expands after the injection and the insulin drips out of the pen. In both cases, you will not receive the full dose of insulin.


If you realize that you have air in the cartridge, perform an air shot. And, as with all pen needles, do not reuse it under any cirumstances. Do you have further questions concerning the use of pen needle or injecting yourself in general ? If so, please contact your diabetes team or consult the instructions for use.


Tips: single use only

✔ Use a new pen needle for every injection.

✔ Multiple use damages the needle and makes injecting more painful.

✔ The insulin dose can be distorted because of a blockage or air in the cartridge.

✔ Put the new needle onto the pen just before you inject yourself.

✔ When you have finished, dispose of the needle right away.



3. Frid A. et al., New Insulin Delivery Recommendations, Mayo Clinic Proceedings, September 2016; 90(9):1231-1255.

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