Quick answer: Priming insulin pens removes the air bubbles and ensures your insulin dose is accurate. To do it, select two units, point the pen up, and press until insulin drops appear. It's fast, simple, and essential before every shot.
While insulin pens are easy and convenient for people with diabetes who receive insulin therapy, misusing them, especially skipping the priming step, can seriously impact blood glucose management.
According to the American Diabetes Association, many diabetic patients often forget to prime their insulin pens. Let's explain exactly how to prime an insulin pen, why it's essential, and what could happen if you skip this critical step.
Related article: Does insulin need to be refrigerated, and how to store it properly?
Why priming your insulin pen is important
Priming an insulin pen means preparing your pen for injection by expelling a few units of insulin into the air. This removes air bubbles and ensures the pen and needle are working correctly.
It's necessary before every insulin injection, whether you're using an insulin pen, syringe, or any injection device.
Related article: A step-by-step guide to using insulin pens for injection
What happens if you don't prime an insulin pen?
Skipping the priming step can lead to:
- Partial insulin dose (if bubbles are present)
- No insulin dose (if the pen is defective)
- High blood sugar or hyperglycemia
💡 It's important to note that injecting air bubbles subcutaneously is not dangerous, but it means you're getting less insulin than prescribed. That small difference adds up fast, especially if you're injecting multiple times a day.
Related article: What happens if you miss a dose of insulin?
Bubbles in insulin pens: why they happen and why they matter
Why should you remove air bubbles before injecting
The most crucial reason for priming an insulin pen is to eliminate air bubbles in the pen and ensure you're getting your full dose of insulin.
Air bubbles commonly form due to:
- Temperature changes
- Atmospheric pressure shifts
- Shaking or vibrating the pen
These bubbles take up space inside the cartridge. If you skip priming, you may inject less insulin than intended, resulting in poor blood sugar control.
Related article: How to Check If Your Insulin Pen Is Empty and the Best Way to Dispose of It Safely
Insulin pen priming: making sure the needle works
Why prime every time you attach a new needle?
Insulin pens use disposable needles; a new one should be used for each injection. Priming helps verify:
- The needle is correctly attached
- It is not clogged or damaged
- The pen isn't jammed or defective
Even though issues like a blocked needle or broken reservoir are rare, they can lead to missed doses or no insulin delivery. Priming is your safety check.
Related article: What Happens When Insulin Gets Warm? Risks, Effects, and Essential Storage Tips to Keep It Safe
How to prime insulin pens step by step
Priming is quick and straightforward. Here's a refresher on how to do it correctly.
Step-by-step instructions
- Screw the disposable needle onto the insulin pen.
- Remove the outer and inner caps from the needle. Discard the inner cap, but keep the outer one for later.
- Turn the dose knob to select two units of insulin.
- Hold the pen upright with the needle pointing up.
- Tap the cartridge to bring bubbles to the top.
- Push the injection button fully to release insulin into the air. You should see at least one drop of insulin.
- Repeat steps 3 to 6 if no insulin appears. If still unsuccessful, try a new needle. If a new needle doesn't work either, your pen may be defective-do not use it.
How many units should be used for insulin pen priming?
The standard recommendation is to prime with two units of insulin, but some manufacturers suggest using three units.
You may need to use more if:
- The pen is new
- There are a lot of bubbles inside
Always prime until you see insulin at the needle tip and no more air bubbles.
Related article: Can You Safely Put Insulin Back in the Fridge? Storage Tips to Keep Your Insulin Effective
Do you prime insulin pens every time?
Yes, you must prime your insulin pen before every single injection.
Even though it might feel like wasting insulin, the risk of underdosing is far more significant. A 1-2 unit error across several daily injections could mean you're missing up to 10 units of insulin daily-a big deal for blood glucose management.
Final Thoughts on priming your insulin pen
Failing to prime your insulin pen can lead to inaccurate insulin delivery and poor blood sugar control.
Don't skip it, and if you're unsure whether you're doing it correctly, speak with your healthcare provider or diabetes educator.
Whether you're new to insulin pens or have been using them for years, making priming part of your injection routine is a small step that makes a big difference in managing your diabetes effectively.
Key Takeaways:
Be sure to remember these key points:
💉 Priming an insulin pen removes air bubbles and ensures full, accurate insulin doses.
🧪 Always check needle flow by priming before every injection-you'll know your pen and needle are working.
⚠️ Skipping priming can lead to underdosing, which may cause hyperglycemia or poor blood sugar management.
🔁 Yes, you must prime every time, even if it feels repetitive-it helps avoid errors and protects your health.
We'd Love to Hear From You!
💬 How often do you prime your insulin pens? What tips or tricks do you use to remember this important step? Share your questions, experiences, or advice in the comment section below. We're all in this together, and your insights could help others on their diabetes journey!
📆 Article Update History:
✅ Updated: April 17, 2025
Originally Published: December 29, 2022
References:
[1] Trends In Insulin Pen Priming, O'malley Grenye; Selassie J. Ogyaadu; David W. Lam; Lisa M. Norlander; Jessica Robic; Camilla M. Levister;Stacey Anderson; Liana Hsu; Sarah E. Loebner; Laya Ekhlaspour; Marc D. Breton; Bruce A. Buckingham; Carol J. LevyDiabetes 2018;67(Supplement_1):83-Lb Https://Doi.Org/10.2337/Db18-83-Lb
