Effects, Types of Insulin and their Side Effect - Health Education - DesiMD Healthcare - India
Health Education


Authored by DesiMD Doctor on 19 Mar 2013 - 14:33

Insulin is a natural hormone produced by the Pancreas, in an area called the Islets of Langerhans. Its key function is regulating carbohydrate and fat metabolism. It signals cells in various areas throughout the body to increase uptake of glucose to be used as energy in the mitochondria, or to be stored in the liver and muscle as glycogen. Insulin also inhibits the use of fat as energy, and poor insulin control is the main reason people fail to lose weight effectively.

Insulin, under normal conditions, is present in the body in sufficient quantities to handle glucose uptake, but is inhibited in certain medical conditions. Diabetes and metabolic syndrome are two of these disorders.

When insulin control becomes inadequate, it frequently results in Diabetes Mellitus. Under these conditions it becomes necessary for the patient to use oral anti-diabetic medications, or insulin itself. Patients diagnosed as Type 1 Diabetic are those who require external sources of insulin, since the hormone is no longer produced by the body. Type 2 Diabetics have a relative insulin deficiency, or loss of potency that can be supplemented by oral medications.

Effects of Insulin
• Increases protein synthesis and DNA replication
• Controls activity of various enzymes
• Controls cellular intake of mainly glucose and fat into muscle and adipose (fat) cells
• Decreases lipolysis (fat breakdown) and proteolysis (protein breakdown)
• Promotes storage of fat( hence the high incidence of diabetes and high cholesterol)
• Increases acid (hydrochloric) secretion in the stomach

Types of Insulin

Insulin can be classified according to the duration/speed of action, or its source.
It may be obtained from bovine (cow/beef), porcine (pork/pig) or recombinant (human) sources.

In most instances, it is more important to classify insulin based on the speed/ duration of action. These differences determine how often and when it is necessary to take it, to ensure adequate uptake of glucose into cells.

Following is a brief overview of the different types of insulin available:

Rapid acting Insulin

These types of insulin are injected just around meal time (just before or after). They work very quickly to accommodate the spike in blood sugar that will follow. It is important to note that due to their speed, they have the greatest tendency to cause low blood sugar (hypoglycemia). It is wise to administer together with a longer acting variety to ensure reasonable coverage. The most common rapid acting varieties available include Humalog (lispro), Novolog (aspart) and Apidra (glulisine). Although small differences in action exist between them, general onset is between 10-30 minutes, with duration of action between
1 - 5 hours.

Short acting Insulin

This variety of insulin will normally be taken before meals. They are often referred to as neutral or regular insulin. They do not act as fast as rapid insulins, and need to be taken a bit before a rapid would. They may be sourced from either animal or human origin, and still possess the risk for hypoglycemia. This is also the group of insulins that most closely mimic natural insulin structure and effects. In general, these insulins have an onset of action between 30-60 minutes, and have duration of action between 2- 8 hours.

Intermediate acting Insulin

Intermediate acting insulins are normally used in conjunction with a faster acting counterpart, since by themselves they are insufficient to control postprandial (after meal) blood glucose spikes.  These insulins have a tendency of causing nocturnal (nighttime) hypoglycemia more than most other insulins, so timing is crucial. The commonly available insulins of this class are Lente insulin and NPH (Neutral Protamine Hagedorn). These drugs have an onset of action ranging between 1-2 ½ hours, with duration of action between 18-24 hours.

Long acting Insulin

Long acting insulins, similar to all longer action insulins, are commonly used together with a more rapid acting version, to allow fast resolution of blood sugar levels. In theory, this would be the best type of insulin since there would be no peak in activity; just a maintained release pattern.  The two most common insulins of this class are Lantus and Ultralente, which have onsets ranging between 30 minutes and 3 hours, with duration of roughly
10- 24 hours.

Side effect of Insulin
Side-effects from insulin usage are rare, but can be serious when encountered.

The most commonly encountered side effects are:

  • Hypoglycemia: To avoid this occurrence ensure to eat at regular intervals or around timing of shots.
  • Irritation at injection site: Generally as a result of poor surface preparation or faulty administration technique.
  • Allergic reactions: This may be the worse encountered side effect; it can be fatal if not attended to promptly. It is best to avoid certain sourced insulin if conscious of allergies.

Insulin is a great addition in the arsenal to fight diabetes, but only when used judiciously. Improper usage can result in poor control of blood sugar, or even worse harm. Please consult your doctor before utilizing an insulin preparation.


This is not a medical advice. The content is for educational purposes only, please contact your doctor for any health care issue.