Product Reviews

BD Micro-Fine + 4mm Pen Needle

BD Micro-Fine + 4mm Pen Needle

Product guide written by Diabetes Expert: Sue Marshall


BD (or Becton-Dickinson) is a brand name in the world of needles. A brand familiar to many of us who have to take insulin injections. Many of us will recall BD disposible syringes, indeed some may still use them.

Buy BD Micro-Fine Needles in the Diabetes Shop:

4mm needles

For those that moved on to insulin injection pens, then you may be using existing BD needles. Here we have a new, smaller-than-ever-before needle, coming in at only 4mm. So is smaller better? Based on the research undertake, it seems that it is.

There are a couple of factors. First, injections should be subcutaneous (under the skin) and not intra-muscular.

Pinch or fold skin?

There have been debates over the years about whether to not to pinch a fold of skin to inject into. There are arguments both for and against. This new shorter needle actually takes away the need to pinch a fold of skin.


One of the thing that can happen in the diabetes sector is akin to reinventing the wheel. Most of inject, some of us are going to pumps and some control their diabetes by other means. If you do inject, then one of the little bits that goes with the kit is the needle. BD, who you might be familiar with thanks to disposable syringes, have brought out the shortest needle on the market which is only 4mm deep. One of the things they’re trying to address is that when it comes to injection technique, people don’t necessarily do the right thing.

First off, we all have fat on our bodies. Primarily, you’re not supposed to inject intramuscularly, it’s supposed to be subcutaneous. In the very old days, when you had much longer needles you were taught to go sideways so you made sure your needle was under the skin and not going into the muscle.

Now with the new tiny needle, it’s almost impossible to go intramuscular. So it helps people with diabetes to achieve the right technique by not allowing them to do the wrong thing, as it were. These are widely available. People who are very young or looking after children with diabetes find them attractive as with little people, little needles makes a lot of sense.

There’s not an awful lot of modification of products for children mainly because as a demographic, there’s not a lot of children with diabetes. However, if you do have diabetes as a child, all the little things that can be helped to be scaled to your size make a lot of difference. The 4mm needle is not primarily for children, it can be for anyone, but it can help you to not resent the pain or inconvenience of injecting.

Certainly, if you use a new needle per injection the chances of you feeling it are very slim indeed.

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Intra-muscular injections

Research has shown that the incidence of an intra-muscular injection with a 12.7mm needle is 45% as it’s big enough to go through the skin, the layer of fat we all have under the skin, and straight into muscle. The risk of an intra-muscular injection is minimised with the 4mm pen needle.

With a 90° insertion angle and no lifted skin fold, there is no risk of intra-dermal injections but the risk of an intra-muscular injection dramatically increases with needle length.

The diagram belows displays how the 4mm needle is adequate for not piercing muscle.

With poor blood glucose control due to intra-muscular injections it is clear why a lifted skin fold has often been recommended in the past. Unfortunately research has shown that almost two thirds of people with diabetes who inject do not use a lifted skin fold when injecting, with the subsequent increased risk of an intramuscular injection.

The second diagram below displays a summary of pain level of first pen needle used and current pen needle on different attributes.

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