Patient Guide to Insulin

What You Need to Know about Insulin

Get the Basics on the Types of Insulin

Toxicologists, scientists, and pharmaceutical researchers have developed different types of insulin derived from and formulated with other compounds.  Doctors and patients have many different types of insulin drugs to choose from including delivery methods and devices.

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

This led researchers to investigate human insulin synthesis by developing a chemically identical drug with the help of DNA recombinant (rDNA) technology.  Today, almost all insulin prescribed is recombinant DNA human.

While only a brief overview of where insulin comes from is presented, it is important for you to know there are many types.  Your doctor makes his or her recommendation based on your diabetes, blood glucose (blood sugar) levels, and lifestyle, and from his or her experience with the insulin.  Whatever type of insulin your doctor prescribes, keep in mind that it is regulated and approved by the US Food and Drug Administration (FDA), who oversees medication safety and efficacy.

Possible Insulin Complications
As with any drug or treatment, side effects and complications are possible.  Your doctor understands the possible risks (associated with insulin and other medications he or she prescribes.  This is another reason to share your complete medical history including allergies, daily medications, and supplements (e.g., vitamins, herbs) with your doctor. 

Types of Insulin
Considering your body’s glucose levels change in response to foods you eat, energy expended, stress, and many other factors, different types of insulin were developed to better care for the needs of persons with diabetes.  The insulins currently available are used to mimic the action of the pancreas. The pancreas normally releases a small amount of insulin 24 hours a day (basal insulin) and in response to food (bolus insulin).

The American Diabetes Association characterizes insulin by the way it works.

  • Onset is defined as the length of time insulin hits your bloodstream and begins to lower blood glucose.
  • Peak is the time during which insulin is at its “peak” or maximum effectiveness at lowering blood glucose.
  • Duration is the length of time insulin continues to lower blood glucose.

Of course, persons with diabetes are individuals, so you should expect deviations in the amount of time any of these medications reach your bloodstream, begin to take effect, peak, and sustain glucose levels.  Rely on your doctor’s advice to help you anticipate how you may react.

The types of insulin used to treat diabetes are listed and briefly explained.  All insulin comes to you in liquid form. 

Rapid-acting insulin begins to effect blood glucose about 15 minutes after injection.  While rapid-acting insulins may peak in an hour, they continue to work after a few hours.  Rapid-acting insulin should be injected before a meal.  Do not delay eating a meal when using rapid-acting insulin.

Regular or short-acting insulin reaches your bloodstream usually within 30 minutes after injection.  It peaks in the 2-3 hour range and stays effective for 3-6 hours.

This type of insulin includes NPH (neutral protamine hagedorn) that help control glucose for 10-12 hours.  A protamine is a type of protein that slows the action of insulin.  NPH is partially named after Hans Christian Hagedorn, who was instrumental in leading insulin research beginning around 1923.  He was the one who discovered that adding protamine to insulin prolonged its effect.

Long-acting insulin enters the bloodstream 1-2 hours after injection and may be effective for as long as 24-hours.  An advantage to long-acting insulin is avoidance of a pronounced peak and more closely works like normal pancreatic basal insulin secretion.


  • Premixed insulin contains a combination of two different insulin products. The mixtures contain a rapid- or short-acting insulin with an intermediate acting insulin. Different mixtures are available.  It eliminates the need to draw insulin from more than one bottle.

Important:  Unless directed by your doctor, never combine or mix different insulin medications.  If you experience a reaction or if you have concerns or questions, contact your doctor.

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Insulin Delivery