Diabetes and Pen Needles

What You Want to Know About the Length and Thickness of Your Pen Needles

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If you are using a pen device and missing injections because of discomfort or pain, then you must find a solution. No one needs to feel pain when injecting insulin or other medications. The needles of today are made very thin and short. And because insulin and other injectable medications for diabetes, such as GLP-1s, should be injected into subcutaneous or "fatty tissue," an extra long needle is not necessary.

In fact, studies have shown that glycemic (blood sugar) control does not change based on needle length. For those persons that are considered to be overweight or obese, they do not need a longer needle either. Studies have also shown that smaller needle lengths (as small as 4mm) do not impact the function of administered insulin and there also seems to be no difference in insulin leakage. And more importantly, those persons who use shorter needles are more likely not to miss injections.

How Do I Know the Size of My Needle?

Pen needles are measured by thickness and length. Most pen needles range from 4mm-12mm in length and 29-32 gauge in thickness or diameter. The higher the gauge, the thinner the needle, while the lower the mm the shorter the needle. If you are experiencing pain, you may want to assess your needle size and length and perhaps ask your physician to switch to a shorter, thinner needle.

What is the Smallest, Thinnest Needle?

The smallest, thinnest needle is the nano 4mm, 32 gauge needle. By comparison, this needle is thought to be as thin as two strands of hair. The risk of injecting into muscle tissue is very rare when using this needle. In fact, BD, the company that makes the BD ultra-fine nano needle - a 4mm, 32g needle - suggests that for those using this needle there is no need to even pinch the skin.

However, you must still inject at a 90-degree angle and hold the needle at the injection site for at least 10 seconds. There are videos available to show you how to correctly use an insulin pen.

What Should You Do if You are Using the Smallest Needle Size and Still Experiencing Pain?

There are other controllable factors that can help to reduce pain at the injection site:

  • Refrain from injecting cold insulin. Cold insulin can sometimes sting - it's best to inject insulin at room temperature.
  • If you are using alcohol to clean your injection site, allow it to dry before injecting your insulin.
  • Try not to tense up before injecting - relaxing the muscles of the site you are injecting can help. Do not inject into muscle, rather relax the muscle around the fatty tissue you are injecting.
  • Do not jab the needle into your skin, rather use a quick penetration. Inject at 90 degrees and avoid changing the direction of the needle once you are at the site.
  • If a particular injection seems painful you can apply pressure at the site for a few seconds, but do not rub it. Rubbing the injection site can increase absorption and put you at risk of hypoglycemia.


    Kreugel, G, et. al. Diabetes Technol Ther. Randomized trial on the influence of length of two insulin pen needles on glycemic control and patient preference in obese patients with diabetes. Jul 2011; 13(7): 737-741. Accessed on-line. June 21, 2014: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3118929/

    Hirose, T, et al. J Diabetes Investig. Identification and comparison of insulin pharmacokinetics injected with a new 4-mm needle vs 6- and 8-mm needles accounting for endogenous insulin and C-peptide secretion kinetics in non-diabetic adult males. May 6, 2013; 4(3): 287-296. Accessed on-line. June 23, 2014: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4015666/

    Hirsch, LJ, et. al. Curr Med Res Opin. Comparative glycemic control, safety and patient ratings for a new 4mm x 32G insulin pen needle in adults with diabetes. June 26, 2010; (6): 1531-41. Accessed on-line. June 21, 2014: http://www.ncbi.nlm.nih.gov/pubmed/20429832

    BD. Injecting with a pen needle. Accessed on-line. June 21, 2014: http://bd.com/us/diabetes/page.aspx?cat=7002&id=62855

    American Association of Diabetes Educators. Strategies for insulin injection therapy in diabetes self-management. Accessed on-line. June 21, 2014: http://www.diabeteseducator.org/export/sites/aade/_resources/pdf/research/aade_meded.pdf

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