Insulin Pen 

Why might I not like insulin pens?

 • Insulin pens are not right for 100% of diabetes patients. Insulin in pens and cartridges is generally more expensive than bottled insulin and syringes. When pens are used a small quantity of insulin is wasted, making the process less economical.

• Not all types of insulin are available to be used in insulin pen cartridges at this stage. Furthermore, insulin pens do not let you mix two different types of insulin, meaning in some cases two separate injections will need to be administered.
https://www.diabetes.co.uk/insulin/diabetes-and-insulin-pens.html#google_vignette