As each system has its advantages and drawbacks, the choice of a pen or a syringe to administer insulin has to be made jointly with your nurse and/or doctor. By explaining the different insulin injecting devices available, they will help you to choose the one that suits you best.
Some insulin treatments combine both insulin pen use for one type of insulin and syringe for another type.
You may also require two insulin pens if your treatment involves two different insulin types.