Insulin: Types, Storage and Usage

Insulin is essential as part of the body’s normal metabolism. Without it, your health will deteriorate until death occurs. When the body lacks insulin, it is necessary to supply it artificially, and there is a variety prescribed today by doctors. Insulin is manufactured in several different forms or types. Sometimes, diabetics must use a combination of insulin types to achieve an important goal – the ability to control blood glucose levels.

Reason for different forms of administered insulin:

In normal healthy conditions, your body is circulating a fairly small amount of insulin on a routine basis. A diabetic with dysfunctional insulin responses requires the body to be provided with a type of insulin that reproduces this natural condition as close as possible. This is called “basal” insulin. It is the equivalent of the amount of insulin that is usually in the bloodstream between meals and over night.

Whenever you eat, the pancreas is stimulated to secrete a more substantial amount of insulin. This is to assist both in the metabolism of the glucose as well as in its removal from circulation. As a diabetic you require insulin that is shorter acting to mimic this action performed by the pancreas. That’s why diabetics inject short acting insulin some 30 minutes prior to eating a meal. This is the insulin referred to as the bolus insulin. The term “bolus” means a mass. Bolus insulin also acts to lower high blood glucose level.[1]

The Clinical Forms of Insulin

There are 4 basic types of clinical insulin[2]. They are classified according to their action and are as follows:

  • Rapid acting insulin – This form of insulin is usually taken just prior to a meal.  It is also the type used in hospital emergency rooms. It deserves its name since it acts in 15 minutes, reaches a peak of action in 1-2 hours and is finished up in 3-4 hours. This can act as basal insulin.[3]
  • Regular or short acting insulin – This form of insulin is also usually taken before a meal. It is slower, acting in 30 minutes. Regular insulin usually reaches a peak of action in 2-3 hours and is finished up in 3-6 hours.
  • Intermediate insulin – This form of clinical insulin is called N or NPH. This stands for Neutral Protamine Hagedorn. It is longer acting than either rapid acting or regular insulin. It is meant to be given twice a day. Intermediate insulin acts in 2-4 hours, reaches a peak of action in 4-10 hours and is finished up in 10-16 hours.
  • Long acting insulin – This form of insulin is used as a general base in a mix. It starts acting in 1-2 hours. However, long acting insulin does not peak and is not finished up until 20-24 hours later. This form of insulin is used to act as the basal insulin.

When using insulin, remember it is packaged differently by various companies. While all types may be classified as intermediate or fast or short acting or long acting, it is always wise to stick to whatever brand you have been prescribed.  This ensures you are receiving the specific dosage and kind of insulin you require for your particular type of diabetes.

Clinical Utilization of Insulin

The clinical strength of insulin is measured in “units.” It is packaged in 100 units per milliliter (ml or cc – same thing).

Establishing the right dosage has a component of trial and error. The insulin amount must be adjusted to the amount of glucose intake and exercise output. The initial requirement for each day is calculated generally by the factor of 0.3-0.5 against body weight. As a result the following holds true: A child who weighs 70 pounds (32 kg) would at first be given each day a total of 10 units of insulin. This total sum will be divided into two parts: long use and bolus use. This is accomplished by halving the amount for each. As a result, the 70 pound child would receive 5 units of long and 5 units of short acting insulin. While the basal insulin can be given once per day because it lasts 24 hours, the short acting insulin will be subdivided further in order to fit the pattern of natural insulin use within the body. The bolus dose is split up into three doses to be taken 30 minutes before the meals, and allocated according to how much carbohydrate there is in each meal.While these calculations are daunting at first site, you doctor will do the calculations for you and advise you on the exact amount you should start with for both the basal and bolus doses.

The guide to determining the right dosage and timing is based on several medical tests but trial and error also enters the picture. That’s why recording glucose meter readings every day plays an important role in diabetes management. You have to read and record your glucose levels regularly because it’s the only way to determine the typical rise and fall of glucose blood levels throughout the day based on your unique diet and lifestyle. Reading should be done:

  • Upon awakening in the morning
  • Before meals
  • Between meals
  • Following meals
  • Before bed

Sticking to this practice will eventually determine the pattern you will come to regularly use for administering your insulin. It may never be an exact science or a fixed quantity, but it will reflect an understanding of your own insulin requirements. Once your insulin requirements are more stable, you may be able to reduce your glucose readings to three times per day.

Taking Care of Your Insulin

You cannot leave your insulin out in the fresh air or on the counter top. It is true that it can survive room temperature for a maximum of 4 weeks, but this is not the way to safely store it. Insulin is a biological material. It is a protein that is made inactive when exposed to heat. Like much of the fresh food you eat, it must be kept cool. This means you need to find a suitable place for it in your refrigerator. Insulin pens can often be left out at room temperature more safely. Be sure you can see the expiration date clearly.[4] If you do not use the insulin within the designated period, discard it according to the requirements of your doctor and/or municipality.


Insulin is a protein required by your body to function. A lack of it results in illness and death. You can replace the insulin in your body artificially. Doing so requires a prescription from your doctor for the right type of insulin and delivering it according to the needs of your body. This will require some trial and error as it is not an exact science. Keep a record of your blood sugar levels and you will be able to establish a typical pattern that can be used to manage your insulin administration.


[1] Warshaw, HS; and Pape, J (2009). Real-Life Guide To Diabetes. Alexandria, VA: ADA.

[2] US Department of Health (2011). “National Diabetes Information Clearing House: Types of Insulin.” Retrieved from

[3] Allison J. Hahr, AJ; and Molitch, ME (2010). “Optimizing Insulin Therapy in Patients with Type 1 and Type 2 Diabetes Mellitus: Optimal Dosing and Timing in the Outpatient Setting.” Disease-a-Month, 56 (3): 148-162.

[4] American Diabetes Association (2009). Type 2 Diabetes. Your Healthy Living Guide. Alexandria, VA: ADA.

This article was originally published July 12, 2012 and last revision and update of it was 9/10/2015.