"Insulin" is commonly used as a generic Blood Sugar Formula Review term for a multitude of different types of insulin that are available. When you shop for a new "car," you may come home with an SUV, a pick-up truck, a sports car, a sedan, or a minivan. All these different "cars" have a different function, just as different types of insulin have different effects.
Insulin has been used since the 1920s in the treatment of diabetes. Initially, purified pork and beef insulins were utilized; however, patients could develop antibodies or symptoms of an allergic reaction to these "foreign" substances. Consequently, human insulin was developed for pharmaceutical use in the 1960s. The 1990s saw the development of genetically altered "analog" insulins; these have become the standard of care today.
The older human insulins that are still available and used today are short-acting and intermediate-acting insulin. These human insulins vary significantly in their day-to-day action within the same person, producing a higher incidence of hypoglycemia. Their peak is such that it requires the patient be eating at the time of peak action to prevent the onset of hypoglycemia. I limit the use of these insulins, believing that the patients who take them are "working for their insulin," rather than "having their insulin work for them".