All About Insulin Pens

Insulin injections can be a daily hassle for people with Type 2 diabetes. There’s a lot to handle when using a vial and syringe, and the needle attached can be a bit intimidating. But injections are much easier with an insulin pen – giving everything you need for an accurate, sterile insulin dose in the palm of your hand. We go over everything you need to know about insulin pens and why you may want to make the switch.

Insulin Pens Explained

Taking insulin is a big part of diabetes self care and insulin pens offer a more convenient, simpler option than the traditional vial and syringe method.

An insulin pen is made up of an insulin reservoir or cartridge (on a reusable pen), disposable needle and a dial or knob to adjust dosage. You simply adjust the dosage and press the injection button.

Using a vial and syringe involves precisely measuring each dose and keeping the syringe intact and clean. It also means carrying around a few items of syringes and vials.

And many popular insulin brands and products are also available in pen form. This includes long acting insulins likes Tresiba and Lantus, and fast acting insulin like Lyumjev.

Types of Insulin Pens

There’s basically two main types of insulin pens: disposable and reusable.

Disposable Pens

Disposable pens come prefilled with insulin and each injection may only use a portion of the insulin. Once all the insulin has been used (or has expired), then the entire pen is thrown away after it’s used.

insulin pen solostar
Lantus SoloStar

Some examples are the Novo Nordisk FlexTouch, Lantus SoloStar and Eli Lily KwikPen.

Reusable Pens

Reusable pens on the other hand use an insulin cartridge, which can be removed and replaced. So only the insulin cartridge is disposed but not the whole pen. Some examples are the Novo Nordisk NovoPen and Eli Lily HumaPen Luxura.

Smart Insulin Pens

As wireless technologies have gotten better and smaller, it’s even made its way to insulin pens!

smart insulin pen
Source: MedTronic InPen

MedTronic’s InPen pen uses Bluetooth technology to sync data on a smartphone app in order track dosage info, time doses and even calculate dosage based on your glucose levels.

Why To Use an Insulin Pen (Or Not)

Insulin pens offer a lot of benefits but also have their drawbacks. Talk to your healthcare provider about whether using an insulin pen is best for your condition.


  • Convenient – everything you need to take inulin in one hand
  • Get exact dosing without measuring
  • Pens are compact, making it easy to store and travel with
  • Available with thinner needles
  • Better for shaky hands or poor vision
  • “Smart” insulin pens have advanced features

The main advantage of an insulin pen is the convenience and ease of taking insulin. A single pen has all you need and there’s no hassle of measuring insulin like you have with a syringe and vial .

Also, some people are more afraid or uncomfortable with using a syringe uncomfortable. A pen on the other hand can be less intimidating and easier to handle.


  • Pen and insulin cartridges often cost more than a vial and syringe
  • Max dosage not as high as a syringe
  • expire faster than vial and syringe
  • Medical insurance may only cover certain insulin pens

But the higher costs of using an insulin pen compared to the syringe and vial is a big drawback. Syringes are inexpensive and insulin vials hold more volume than cartridges, which means more doses per vial.

Also, adjusting the insulin dose with a pen is more limited than a syringe. For example, syringes can handle up to a 100 units but an insulin pen can only handle up to 60-80 units. So if you need a dose of 85 units, you’ll need to take two injections with an insulin pen while a syringe will handle that in one injection.

How to Use Insulin Pens

Always follow the instructions of the pen you’re using. But to give you an idea, below are general steps of using a disposable insulin pen (using reusable pen is similar but with the added step of inserting/removing a cartridge).

Abdomen injection site
  1. With clean hands, remove the pen’s cap and check the reservoir for cloudy insulin (which you shouldn’t use if you do).
  2. Attach a new needle (some come with a sterilizing pad).
  3. Prime the pen by turning the dose adjuster by a couple units, hold the needle straight up, and tap the pen a few times (to get air bubbles out). Press the injection button and you should see a few drops come out.
  4. Select the correct dose by turning the dose adjuster. Note, most pens only go up to 60 or 80 units.
  5. Place the pen on an injection site – usually the abdomen, upper arm or thighs. Inject the dose by pressing the injection button with your thumb and hold for about 10 seconds to make sure all the insulin is injected.
  6. Pull the needle from your skin, slowly remove the needle from the pen and dispose the needle.
  7. If there’s not enough insulin for a later dose, dispose of the pen. If there is enough, replace the cap and store.

Storage and Travel

Insulin pens are small and lightweight, making them easy to store and travel with. Pens usually come with a handheld storage case with room for several insulin cartridges. But there’s plenty of aftermarket insulin pen cases, wallets and other styles to choose from.

Insulin pen case

Proper Temperature

Insulin should be kept away from direct sunlight or heat because it can damage the integrity of the insulin.

For unused pens, manufactures usually recommend that you store them in the fridge (between 36° – 46°F) but should not be frozen. For open or in-use pens, they should be stored in room temperature and away from sunlight or heat.

And make sure to read the insulin pen instructions for the expiration date and when to dispose of open/in-use pens.

Travelling with Insulin

Because insulin has to be kept cool, travelling, long commutes or even where you work can make it hard to store insulin properly. A simple solution is to use a small insulated lunch/food bag with an ice pack and that should keep it cool for several hours.

But if you want something designed for insulin pens, you can find a variety of insulin travel cooler cases. They have compact handheld cooler cases that use small ice packs, and others that resemble insulated “water bottles” that can store more pens and insulin cartridges.

Depending on the style you choose, these cooler cases can keep insulin within temperature anywhere from 5 hours to up to 24 hours.

Disoncare travel cooler


How to dispose of insulin pens?

Needles should be disposed of in a sharps container but if you don’t have one, using a strong plastic container can work.

Check with your local waste provider for disposing the container and your local pharmacy, medical office and fire department may also accept them. The insulin pen is usually just discarded in the trash.

How to calculate how many insulin pens per months?

Take the number of units per day of insulin you’ve been prescribed and multiply by 30 days. This gives you the total insulin you’ll need in a month.

Then divide that by the number of units in one insulin pen, which will give you approximately the number of pens you’ll need in one month.

How long does an insulin pen last?

This will depend on the specific insulin pen you’re using and will say in the instructions. Generally, disposable insulin pens can last anywhere form 14 to 28 days after the first use. For a reusable pen, check the insulin cartridge’s labeling and instructions for the expiration date.


Insulin pens make taking insulin a lot easier, faster and overall more convenient than the standard vial and syringe method. You have everything you need in a single pen without the hassle of measuring. Using these pens are really simple – attach a needle and cartridge, adjust dosage, inject and dispose of the needle – that’s it.

But insulin pens generally cost more than a vial and syringe and your health insurance may only cover certain pens. And they do need to be kept cool and stored properly so you may want to invest in a good insulin pen cooler or travel case.

If you have the option to switch, insulin pens offer a lot of benefits, take away the hassles of insulin injections, and is a great tool in your daily diabetes management.

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