How Many Times Can You Reuse a Syringe?

Medical review by Elizabeth Gomez, MSN, FNP-BC

Whether you’re new to insulin injections or if you’ve been using them for decades, at some point the thought has definitely crossed your mind: “Can I reuse my syringes?”

There are at least two tempting reasons to reuse your syringes: it saves money, and it saves hassle. Every member of the Diabetes Daily staff will admit to having at least occasionally re-used syringes, lancets, and insulin pen tips.

But it’s important to know that medical authorities universally agree: you should never reuse syringes. This article will discuss the risks.

The Blunt Truth

Syringes, insulin pen tips, and lancets (used to prick the fingertips for glucose meters) are all manufactured to be used only once. Simply put, they’re not built to penetrate your skin multiple times. Every time you use one of these sharp implements, the needle’s tip degrades.

If you spend time in the diabetes online community, you may have seen photos of what are supposedly magnified images of syringe tips. Here’s an example of an image that has been shared many times, all throughout the internet:

Pretty ugly, right? We’re not sure where this image actually comes from, and therefore cannot verify that it’s real. Here’s an image that we know is legitimate, published in an academic journal in an article specifically about pen needle tips:

While we don’t know how many times this needle was used, the takeaway should be clear: needles suffer degradation after use that cannot be assessed with the naked eye. And remember that this was a pen tip – a syringe, which also has to penetrate the stopper on the insulin vial, may well exhibit even more damage.

So, what’s the problem with a blunt (or ragged or hooked) needle? The first and most obvious problem is that it might hurt. Those re-used needles are also more likely to cause bruising or bleeding.

But the damage from a blunt needle may go beyond an ouchie. It’s been proposed that ragged needle tips also contribute to lipohypertrophy, the scarring and unwanted growth of fatty tissues. Lipohypertrophy is a sneaky and surprisingly common complication that can lead to both unpleasant lumpy skin and to declining blood sugar control, because injections into damaged flesh are more likely to be absorbed unpredictably. We all want to avoid lipohypertrophy: it’s the primary reason we are taught to rotate our injection sites.


There also exists a risk of bacterial contamination when you repeatedly inject yourself with the same needle, especially if you are not careful about using alcohol swabs to disinfect your skin (and the insulin vial stopper). While infection is not common, it is a possibility, and a dangerous one at that. Many people with diabetes suffer from a decreased ability to fight off infections.

There is also the chance that you involuntarily help accelerate the degradation of the insulin itself by introducing contaminants into the vial.

And if you leave a pen tip attached to your insulin pen, you have opened a small pathway between the insulin and the outside world. Small amounts of air or fluid can travel through the needle, especially when the pen is exposed to temperature changes, which can reduce dosing accuracy.

What About Lancets?

The recommendation from health authorities and manufacturers on lancets is the same: you should change your lancet every time you use it.

The truth is that it is a very rare patient that changes their lancet every time. According to One Drop, a glucose meter manufacturer, most people change their lancets less often than daily. About one in five patients change their lancets “a few times a year,” or never. There are many lancet memes that joke about this lazy (and very common) tendency.

Lancets are slightly less problematic than insulin, because they do not introduce lipohypertrophy or risk contaminating the insulin itself. But dull and ragged lancets hurt, and if re-used excessively, you may not even realize how much they have started hurting because the change has been so gradual.

Ideally, you should change your lancet as often as possible.

Another Perspective

With all of that said, the absolute risk of needle re-use appears to be fairly low. One 1989 study followed 87 patients with diabetes to see if they actually followed syringe use recommendations. About half of them didn’t, reusing syringes an average of 6.6 times, and only a minority disinfected the way they’d been taught. The results? No harm done, apparently:

No adverse effect of syringe reuse was identified. The authors conclude that diabetic patients frequently reuse disposable syringes, without apparent harmful effect.

This study was small, and did not address pen tip or lancet re-use, so it’s best taken with a grain of salt. But it may be a general indication that the negative effects of needle re-use are somewhat rare.

There may also be some situations in which using a fresh needle is actually more dangerous than not. How so? Well, imagine that you have no way of disposing your old lancet or pen tip properly. You can’t just toss it in the trash, and you certainly don’t want it bouncing around unprotected in your handbag or backpack. In that case, it may be better for everyone if you would just re-use your needle.

You might also find yourself without a fresh sharp when you want to use one – mistakes happen, and plans are upended. It happens to all of us. In that case, you may need to balance the risk of re-using needles against the risk of suboptimal blood sugar management.

The Bottom Line

All health authorities are united when they say that all sharps – whether syringes, pen tips, or lancets – should be used only once.

Many people with diabetes ignore this advice, and the risk of doing so is difficult to quantify.

The best practice is undoubtedly to use a new disposable needle every single time it’s possible. However, there may be some situations where re-using a sharp is the best option.

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