How Needle Size Affects Diabetes Control

Using the smallest needle size for pen insulin injectors may be worth considering. If you find using a pen medication injector to be painful, you may be able to eliminate this problem by switching to a different needle size.

Studies have found short, thin needles deliver insulin as effectively as longer, thicker ones and may be more comfortable to use. Your healthcare provider can help you make an informed decision about whether using a different needle is an option for you and which size to switch to.

This article discusses needle sizes of pen injectors, as well as ways to reduce pain caused by pen injectors.

Benefits of Smaller Needles

Smaller needles can refer to the length of the needle and/or the thickness of the needle.

Needle Length

Injectable medications such as insulin and glucagon-like peptide-1s (GLP-1s) are most effective when injected just below the skin into fatty tissue so the body can easily absorb and use it. Therefore, a long needle isn't necessary.

In fact, if insulin is injected into muscle tissue it will be used up more quickly than is ideal, which could potentially lead to hypoglycemia. What's more, if a needle pierces muscle tissue, it can cause pain, bruising, and bleeding.

Studies show needle length doesn't affect blood sugar control. Needles as short as 4 millimeters (mm) do not appear to impact the function of insulin given. In addition, shorter needles may have an advantage over longer needles: People may be less likely to skip self-injections to avoid pain.

Some people with diabetes worry that a shorter needle may allow insulin to leak from the injection site, but research has shown this doesn't happen.

Needle Thickness

For people who need to inject a large dose of insulin at one time, a thicker needle (lower gauge) may deliver the insulin quicker and avoid medication leaking out from the injection site. However, injecting insulin using thicker needles can be more painful.

Needle Sizes

Insulin pen needles range from 4 mm to 12 mm in length and 29 to 32 gauge in diameter. The lower the number of millimeters, the shorter the needle, while the higher the gauge, the thinner the needle. On average, human skin is 1.6 mm to 2.1 mm thick, so a 4 mm needle will easily go through the skin layer.

3.5 to 4 mm

One of the smallest, thinnest needles is the nano 4 mm, 32 gauge needle, which is about as thin as two strands of hair. These include:

• GlucoRx 4mm: FinePoint Pen Needles Universal Fit 4 mm 31G
• BD Micro-Fine Pen Needles 4 mm
• NovoFine Plus 32G 4 mm

There is even a smaller needle that is 3.5 mm and 34 gauge called:

• Droplet Micron 3.5mm 34G
  

The risk of injecting into muscle tissue is very rare when using these needles, They are so small, in fact, that they do not require pinching the skin while injecting.

Both are considered suitable for adults and children.

6 mm

The 6 mm mini needle usually comes in a gauge of 31 or 32, making it as thin as the 4 mm needle. Options include:

• Unifine Pentips 6 mm
• Novofine Pen Needles 6 mm
• MyLife Penfine Needles 6 mm
• GlucoRx FinePoint Pen Needles Universal Fit 6 mm 31G

8 mm

The 8 mm needle is still short and very thin, with an average gauge of 31, but typically requires pinching the skin to get the most accurate dose.

Options for this length include:

• GlucoRx FinePoint Pen Needles Universal Fit 8 mm 31G
• BD Micro-Fine Pen Needles 8 mm
• MyLife Penfine Needles 8 mm
• Novofine Pen Needles 8 mm
• Unifine Pentips 8 mm

10 mm to 12 mm

The 10 to 12 mm length was once the standard needle size and many people are still accustomed to this length. These needles are very thin, with a gauge size ranging from 29 to 31.

There's a chance that a longer needle such as the 10 mm or 12 mm size may negatively impact thinner patients who have less subcutaneous fatty tissue to get through before reaching the muscle. In fact, 4-, 5-, and 6-mm needles are recommended for all adults with diabetes regardless of their BMI.

Ask your healthcare provider if this length is right for you.

Options for this length include:

• Unifine Pentips (10mm)
• MyLife Penfine Needles (10mm)
• FinePoint Pen Needles Universal Fit 10 mm 31G
• FinePoint Pen Needles Universal Fit 12 mm 31G
• BD Ultra-Fine Pen Needles 12.7 mm 29G

Reducing Injection Pain

There are methods to prevent or lessen pain discomfort while using an insulin pen, regardless of needle size:

• Bring insulin to room temperature. Cold insulin can sting—remove it from the refrigerator 15 minutes before injecting.
• Allow the alcohol to dry. If you use alcohol to clean and prepare your injection site, allow it to dry before injecting your insulin.
• Try not to tense up. Before injecting, take deep abdominal breaths and mentally work to relax the muscles at the site where you'll be injecting.
• Don't jab. Instead, aim for quick, direct penetration. Inject at a 90-degree angle to your skin and do not change the direction of the needle once you are in the injection site.
• Rotate injection sites. Move the injection site by 1 inch with each dose to prevent soreness, irritation, or the formation of a painful lump.
• Press, don't rub. If an injection is painful, apply pressure to the site for a few seconds, but do not rub it. This could increase insulin absorption and put you at risk of hypoglycemia.
• Use a new needle for each injection. Using the same needle repeatedly can weaken the needle and make it dull, causing pain, bruising, or bleeding. Repeated use also increases the risk of the needle breaking and/or causing infection.

Summary

Short, thin needles for pen insulin injectors have been shown to cause less pain and deliver insulin effectively. The needle size that is best for you may depend on how much fatty tissue you have and how much insulin is required with each injection. In addition to changing needle size, there are several ways you can reduce injection pain. Talk with your healthcare provider about which needle size best meets your needs.