Insulin comes in many formulations, sometimes in pens and sometimes in vials. They may be short-acting, rapid-acting, long-lasting, or intermediate in duration of action. An interesting variation  is called "premixed insulin" or "mixture" insulins, because two different insulins of two different durations are premixed at the factory into one solution. They can provide some degree of blood sugar control at meals, between meals, and even at night, depending on your treatment plan and how much...