Insulin: What You Should Know About This Life-Saving Hormone

Millions with type 1 and type 2 diabetes use this hormone to control their blood sugar. Do you know what insulin does and how to use it effectively? Learn the basics here.

How does insulin work illustrationInsulin is the crucial hormone that allows cells throughout the body to convert the glucose from the food you eat into energy.

Ah, insulin. This crucial hormone is the go-between that lets cells throughout your body use blood sugar (glucose) from the food you eat for energy or to store glucose to use later. Without it, glucose could not readily leave your bloodstream and enter your cells.

An estimated 7.5 million American children and adults with diabetes use insulin, according to statistics from the American Diabetes Association.  First used to treat diabetes by Canadian physician and researcher Frederick Banting and others in 1922—a Nobel Prize-winning discovery still hailed as one of medicine’s all-time biggest breakthroughs—insulin “literally began to save human lives” immediately, say the authors of a 2018 report on the cost of insulin in the journal Diabetes Care.

A Brief History of Insulin

Researchers and scientists have developed different types of insulin derived from—and formulated with—a variety of compounds so doctors and patients have a variety of products, and delivery methods to chose from. 

In the beginning, bovine (cow) and/or porcine (pig) insulin was extracted and used to insulin for human use.  While bovine and porcine (sometimes combined) insulin is similar to the human counterpart, their composition is a little different.  Because of this, some patients’ immune systems produce antibodies making bovine and/or porcine preparations ineffective.

Eventually, researchers developed a chemically identical drug with the help of DNA recombinant (rDNA) technology. Today, almost all insulin prescribed is recombinant DNA human. 

Although insulin’s changed a lot over the years, it’s still saving lives. If you or someone you love uses this hormone—or if your doctor has recommended it, here’s what you should know about this life-saving drug:

What is insulin?

Inside your pancreas, special cells called beta cells produce and pump out insulin as needed when your blood sugar begins to rise after you have a meal, snack or carbohydrate-rich drink like juice, soda or even milk. Insulin acts like a key in a lock, fitting into special receptors on cells throughout your body so cells can absorb glucose from your bloodstream. Once inside, glucose is burned for energy.

Excess glucose may be saved up in your liver and sent out into your bloodstream when you need it—such as when you’re hungry between meals or if you’re burning a lot of glucose during exercise or other physical activity. So insulin controls glucose levels in your bloodstream—and make sure it gets to where your body needs it.

Who Needs Insulin Therapy?

Virtually everyone with type 1 diabetes must use insulin, because their own bodies do not produce this hormone (or may make so little that it is not effective). A growing number of people with type 2 are also using insulin – and are starting insulin therapy sooner than in the past. “In type 2 diabetes, insulin resistance makes it difficult for your body to respond to insulin but over time you will also make less and less insulin, as well,” notes Carla Cox, PhD, RD, CDE, CSSD, FAADE, CPT, a spokesperson and fellow of the American Association of Diabetes Educators.  “Half of all people with type 2 diabetes will eventually use insulin, usually along with other diabetes medications.”

Types of Insulin

Insulin today is formulated in a variety of different types. Some work quickly but last for just a few hours, others reach peak levels in your bloodstream more slowly and continue to work for up to 48 hours. Most people who use insulin use several types, with doses and timing carefully developed with the help of their doctor and/or diabetes educator for optimal blood sugar control. Types of insulin you may hear about are:

  • Rapid-acting insulin, which acts within 15 to 30 minutes and lasts about three to four hours. 
  • Short-acting (also called regular) insulin acts within 30-60 minutes and can last five to eight hours.
  • Intermediate-acting insulin (also called NPH), which works within 90 minutes to two hours and reaches peak action in four hours.
  • Long-acting insulin, which works within an hour and may last up to 24 hours.
  • Ultra long-acting insulin, which also works within an hour and may last up to 48 hours.

How Does a Person with Diabetes “Take” Insulin?

You may inject yourself with insulin using a syringe or a pen injector, use an insulin pump that provides a steady supply of insulin all day and night or even use a newer, inhaled insulin.

Less frequently, people receive insulin using a jet injector that sprays insulin into the skin or via an injection port that delivers the insulin under your skin through a short tube.

Today, about 60% of insulin users opt for pen injectors. Disposable insulin pens come prefilled with insulin—you throw it away once you’ve used it up. Other pens take an insulin cartridge that you insert, then replace as needed. They can cost more than using a needle and syringe, but may be easier to use.

Meanwhile, a growing number of children and adults with type 1 and type 2 are opting for an insulin pump, Cox notes. These small machines connect to a small plastic tube and a very small needle that stays in your skin for several days, and then is changed. The machine, often worn on your belt, pumps insulin ‘round the clock. (Another type of pump connects directly to your skin.) 

“No matter how you receive your insulin, I recommend using a continuous glucose monitor with a sensor so you can track how well your dose is working with the food you eat and with your physical activity,” she says. “The information will help you and your healthcare provider make smart decisions about the best insulin therapy for you.”

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