Insulin Pens

Often the size and shape of a large marker, insulin pens carry insulin in a self-contained cartridge. They are easy to use and growing in popularity.

Some users use insulin pens for all their injections, while others carry them when they are "on the go" and rely on less-expensive and more versatile syringes when they are:

  • mixing different insulins
  • taking an insulin that is not available in a pen
  • at home

Insulin pens are used with pen needles that are sold separately. A new pen needle should be used each time you inject.  

Insulin Pen Types

While there are a number of different brands and models available, most insulin pens fall into one of two groups: reusable pens and disposable pens.

  • Before using a reusable insulin pen, you must load it with a cartridge of insulin. Depending on the size of your doses, a cartridge may give you enough insulin to last for several days of injections. When the cartridge is empty, you throw it away and load a new cartridge. With good care, a reusable pen can often be used for several years.
  • Disposable insulin pens come filled with insulin and are thrown away when they are empty.

Disposable pens are generally more convenient than reusable pens because you do not need to load any cartridges, but they usually cost more to use than reusable pens and cartridges.

Pen brands and models differ from one another in many ways. When working with your healthcare team to select a pen, there are many factors to keep in mind, including:

  • The brands and types of insulin that are available for the pen. 
  • The number of units of insulin that the pen holds when full. 
  • The largest size dose that can be injected with the pen. 
  • How finely the dose can be adjusted by the pen. For example, one pen may dose in two-unit increments (2, 4, 6, etc.), another in one-unit increments (1, 2, 3, etc.) and yet another in half-unit increments (1/2, 1, 1 1/2). 
  • The way the pen indicates whether or not there is enough insulin left in it for your entire dose.
  • The styling and appearance of the pen and the material (plastic or metal) that the pen is made of. 
  • The size of the numbers on the pen dose dial and whether they are magnified. 
  • The amount of strength and dexterity required to operate the pen. 
  • How to correct a mistake if you dial the wrong dose into the pen. 
  • The way the pen indicates whether or not there is enough insulin left in it for your entire dose. 

Advantages and Disadvantages

The reasons why some insulin users prefer insulin pens include: 

  • Insulin pens are portable, discreet, and convenient for injections away from home. 
  • They save time because there is no need to draw up insulin from a bottle - it is already pre-filled in the self-contained cartridge. 
  • They usually let you set an accurate dose by the simple turn of a dosage dial, and that may make it easier to set an accurate dose for people who have vision or dexterity problems.

There are also reasons why insulin pens are not right for all users, including: 

  • Insulin in pens and cartridges is often more expensive than insulin in bottles for use in syringes. 
  • Some insulin is wasted when pens are used: one to two units of insulin are lost when the pen is primed before each injection; and there is usually some insulin left in the pen or cartridge (but not enough to inject) when they are used up. 
  • Not all insulin types are available for use in insulin pen cartridges. 
  • Insulin pens do not let you mix insulin types, which means that if the insulin mixture you need is not available as a pre-mix, two injections must be given - one for each type of insulin. 
  • Insulin pens should only be used for self-injection. This is because the pen needle must be removed from the pen after each injection, and there is no way to completely protect the person giving the injection from getting accidentally stuck by the needle while he or she is removing it from the pen.