Ways to Inject Insulin: Syringes and Pens

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Ways to Inject Insulin: Syringes and Pens

When it comes to giving yourself insulin, it’s important to know that you have options. The process of giving yourself insulin is called insulin delivery. Of course, the ideal way to deliver insulin would involve anything without a needle — for example, swallowing a pill, using a nasal spray or wearing a patch. Unfortunately, these methods aren’t available (yet). In the meantime, the most common insulin delivery methods are:

· Syringe and vial
· Pen
· Pump
· Inhaler


Each of these methods has its pros and cons, and, for this reason, it’s helpful to talk out your options with a diabetes educator or your doctor to decide what’s best for you. In this piece, we’ll take a closer look at insulin syringes and insulin pens.

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Insulin syringes

When insulin first became available, a person with diabetes used glass syringes with removable needles that required boiling, soaking and sharpening with a pumice stone. You can imagine how much work that involved! Today, insulin syringes are disposable, and needles are shorter and thinner, making injections much more comfortable than in years past. If you use insulin syringes, you’ll need to draw up your insulin from a vial.

Insulin syringes come in three sizes:

· 3/10 cc syringe holds 30 units of insulin (1/2 -1 unit for each line of the syringe)
· 1/2 cc syringe holds 50 units of insulin (1 unit for each line of the syringe)
· 1 cc syringe holds 100 units of insulin (2 units for each line of the syringe)

The size syringe that you choose should depend on the dose of insulin you’re taking. The larger your dose, the larger the syringe you’ll need (otherwise, you’d need to take another injection).

In addition to choosing a syringe size, you’ll need to consider what size needle to choose. Syringe needles come in three lengths

· 12.7 mm
· 8 mm
· 6 mm

Since insulin injections are given subcutaneously, or into the fat layer just below the skin, you will need to “pinch up” your skin before you inject with a syringe to avoid injecting into muscle. (By the way, if you inject into muscle, the insulin may be absorbed somewhat inconsistently and can raise the risk of low blood sugar).

Insulin syringe needles come in different gauges, or thicknesses. The higher the gauge, the thinner the needle. Syringe needle gauges range from 28 to 31.

One advantage of using insulin syringes and vials is that, depending on the types of insulin you’re taking, you can mix two insulins in one syringe, thereby limiting the number of injections that you need. Keep in mind, though, that many types of insulin can’t be mixed — always check with your diabetes educator or provider for instructions.

Another advantage to using syringes is cost. In most states, insulin syringes can be purchased without a prescription; the cost of syringes varies, ranging from $10 to $40 for a box of 100, depending on the pharmacy. There’s a separate cost for insulin, and that can range widely. Some types of insulin cost up to several hundred dollars per vial, while older types of insulin can be purchased at Walmart for $25.

Insulin pens

These days, many people are using insulin pens to inject insulin. The use of insulin pens has steadily grown in popularity, thanks to their ease of use, accuracy and convenience. Insulin pens look like a writing pen. On one end is a dial to set the dose and a button to deliver the insulin; on the other end is where a needle is attached. Like syringes, pen needles come in different lengths:

· 12.7 mm
· 8 mm
· 6 mm
· 5 mm
· 4 mm

Pen needle gauges tend to be 31 or 32 gauge. When it comes to needle length and gauge, don’t assume that your health-care provider will automatically prescribe you the shortest, highest gauge — make sure to ask! And if you’re concerned that you might need to use a longer needle because of your body weight, don’t be. Research shows that skin thickness is pretty much the same regardless of body fat, age, race or gender. When using a short needle, there is no need to pinch up, either (although very lean people may need to pinch up, even with short needles).

Some insulin pens have a replaceable cartridge, while others are prefilled with insulin and are disposed of when the pen is empty. In addition, some pens allow you to dial up half-units of insulin which is ideal for someone who needs very small amounts of insulin.

There are pros and cons to using an insulin pen. On the “pro” side, pens are generally easier to use than syringes (no drawing up insulin); fewer steps are involved with using a pen. If you have difficulty seeing, you can listen for the “click” when dialing up your dose (each click is equal to one unit of insulin). Plus, if you have issues with dexterity, using an insulin pen is the way to go. A lot of people like using pens because they’re easy to carry and giving an injection away from home, such as in a restaurant, is easier and more discreet than using a vial and syringe.

On the “con” side, insulin pens tend to be more expensive than using syringes and vials if you’re paying for them by cash, although in the long run, the cost tends to come out to be the same. That’s because you get more insulin per pen than you do per insulin vial. Many pens contain 300 units of insulin; so, a box of five pens contains a total of 1500 units of insulin. For comparison, a vial of insulin contains 1000 units of insulin.

Some health plans don’t cover the cost of insulin pens, so you’ll need to check with your plan to find out what’s covered. Insulin pens generally come in boxes of five, although you may be able to get one pen at a time from your pharmacy. You will also need to purchase insulin pen needles separately. They are sold in boxes of 100 (yes, you should change the pen needle each time you use your pen), and can range in price from $15 to $45, although the cost may be covered by your insurance with a prescription.

Another factor to consider: if you take two different types of insulin, you will need two separate pens, which means two separate injections.

There is certainly a lot to consider and think about when choosing how you will inject your insulin. In fact, it can be downright overwhelming, especially when you have to consider needle length and gauge. Don’t hesitate to talk with your health-care provider or diabetes educator about what’s best for you. Your pharmacist can also be a great resource, as well.

Want to learn more about insulin? Read “What Does Insulin Do?” and “Insulin Basics.”

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES on social media

A Registered Dietitian and Certified Diabetes Educator at Good Measures, LLC, where she is a CDE manager for a virtual diabetes program. Campbell is the author of Staying Healthy with Diabetes: Nutrition & Meal Planning, a co-author of 16 Myths of a Diabetic Diet, and has written for  publications including Diabetes Self-Management, Diabetes Spectrum, Clinical Diabetes, the Diabetes Research & Wellness Foundation’s newsletter,, and

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