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October 10, 2017.
What is Insulin Resistance?

Insulin resistance is a decreased ability to respond to the effects of insulin, especially by muscle and fat (adipose) tissues. Insulin is a hormone produced by the beta cells in the pancreas. Small amounts of it are normally released after each meal to help transport glucose into the body's cells, where the glucose is needed for energy production. Since cells must have glucose to survive, the body of an insulin-resistant individual compensates by producing additional amounts of the hormone. This results in a high level of insulin in the blood (hyperinsulinemia) and over-stimulation of some tissues that have remained insulin-sensitive. Over time, this process causes an imbalance in the relationship between glucose and insulin and, without treatment, may eventually cause health complications affecting various parts of the body.

Hyperinsulinemia and insulin resistance is associated with alterations in the concentration and relative amounts of the body's lipids, significantly increasing the amount of triglycerides and LDL (low-density lipoprotein, the "bad cholesterol") in the blood and decreasing the amount of HDL (high-density lipoprotein, the "good cholesterol"). It may also increase a person's risk of developing a blood clot, cause inflammatory changes, and increase a person's sodium retention, which can lead to increased blood pressure.

The cause of insulin resistance is not fully understood. It is thought to be due partly to genetic factors, including ethnicity, and due partly to lifestyle. Most people with insulin resistance do not have any symptoms. In most cases, the body is able to keep pace with the need for extra insulin production for many years. If the body's insulin production fails to keep up with demand, then hyperglycemia will occur. Once glucose reaches a high enough level, type 2 diabetes is present. The high glucose level can damage blood vessels in many organs, including the kidneys. Insulin resistance is therefore a risk factor for developing type 2 diabetes. Changes in lipids can cause fatty plaque deposits in the arteries and lead to cardiovascular disease (CVD) and strokes.

Metabolic syndrome and insulin resistance are two terms that have often been used interchangeably to characterize some of the abnormalities associated with increased resistance to insulin and increased production of insulin, and to recognize these changes as risk factors for future disease. Metabolic syndrome is essentially a subset of insulin resistance; although several different sets of diagnostic criteria for metabolic syndrome exist, all include obesity, alterations in lipid levels, and impaired glucose processing in the definition of this disorder. The goal of screening for metabolic syndrome is to identify and work with obese, sedentary people to decrease their health risks through lifestyle changes.

Insulin resistance is not a disease or specific diagnosis, but it has been associated with conditions such as, as mentioned, CVD, type 2 diabetes, obesity, and hypertension as well as polycystic ovarian syndrome (PCOS) and nonalcoholic fatty liver disease. Some researchers also believe that there may be a link between insulin resistance and certain forms of cancer. The mechanisms of these associations, however, are not well understood. It is important to remember that many people who have these conditions do not have insulin resistance and, likewise, many people who have insulin resistance will never develop these conditions. These are just patterns of association that have emerged. They are frequently seen together and it is thought that insulin resistance may contribute to their development and exacerbate them when it is present.

Accordion Title
About Insulin Resistance
  • Tests

    There is no one test that can directly detect insulin resistance. Instead, a health practitioner will look at an individual's entire clinical picture and may suspect insulin resistance if the person has increased glucose levels, increased levels of triglycerides and LDL cholesterol, and decreased concentrations of HDL cholesterol. Laboratory tests most likely to be ordered include:

    • Glucose. This is usually performed fasting but, in some cases, a health practitioner may also order a GTT (glucose tolerance test, several glucose tests that are taken before and at timed intervals after a glucose challenge). The goal of glucose testing is to determine whether a patient has an impaired response to glucose.
    • A1c. This test reflects average blood glucose levels over the past 3 months by measuring the percentage of hemoglobin that have been glycated, or bound with glucose, in the bloodstream. It is also called hemoglobin A1c, HbA1c, or a glycohemoglobin test.
    • Lipid profile. This measures the HDL, LDL, triglycerides, and total cholesterol. If the triglycerides are significantly elevated, a DLDL (direct measurement of the LDL) may need to be done.
    • One of the most common ways of detecting insulin resistance is by using the homeostatic model assessment (HOMA). It involves measuring glucose and insulin levels and then using a calculation to estimate function of the beta cells in the pancreas that produce insulin and insulin sensitivity.


    Other laboratory tests that may be ordered to help evaluate insulin resistance and provide additional information include:

    • Insulin. The fasting insulin test is variable, but insulin levels will usually be elevated in those with significant insulin resistance.
    • hs-CRP. This is a measure of low levels of inflammation that may be done as part of an evaluation of cardiac risk. It may be increased with insulin resistance.
    • LDL-P. This is a measurement of the number of various types of low-density lipoprotein particles using a lipoprotein subfractions test. It is thought that a greater number of small, dense LDL particles than large, fluffy particles is associated with a greater risk of cardiovascular disease.
    • Insulin tolerance test (ITT). This test is not widely used but is one method for determining insulin sensitivity (or resistance), especially in obese individuals and those with PCOS. This test involves an IV-infusion of insulin, with subsequent measurements of glucose and insulin levels.
    • Quantitative insulin sensitivity check index (QUICKI). This uses a mathematical formula to calculate a number based on glucose and insulin blood tests. Insulin resistance is diagnosed based on where the calculated value lies in the QUICKI index.


    Specific insulin suppression tests may also be ordered in a research setting to study insulin resistance but are not generally used in a clinical setting.

  • Treatment

    Treatment of insulin resistance primarily involves changes in diet and lifestyle. The American Diabetes Association recommends losing excess weight, getting regular amounts of moderate-intensity physical activity, and increasing dietary fiber to lower blood insulin levels and increase the body's sensitivity to it. Weight loss and regular exercise can:

    • Decrease blood pressure
    • Increase insulin sensitivity
    • Decrease triglyceride and LDL cholesterol levels
    • Raise HDL cholesterol levels

    People who are identified by their health practitioners as having insulin resistance should work with their health care provider and with other medical professionals, such as a nutritionist, to develop an individualized treatment plan and to monitor its effectiveness. Drug treatments may also be necessary to control any co-existing conditions or diseases.

View Sources

NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

(2003 April). QUICKI is a useful index of insulin sensitivity in subjects with hypertension. American Journal of Physiology. Vol. 284. Available online at http://ajpendo.physiology.org/content/284/4/E804 through http://ajpendo.physiology.org. Accessed September 2013.

(2008 December). Insulin Resistance May Hasten Diabetes Progression in Certain Patients. Medscape from Reuters Health Information [On-line information]. Available online at http://www.medscape.com/viewarticle/568888 through http://www.medscape.com. Accessed August 2009.

Jeppesen, J. et. al. (2007 May 29). Insulin Resistance, the Metabolic Syndrome, and Risk of Incident Cardiovascular Disease [On-line information]. Medscape from J Am Coll Cardiol. 2007;49(21):2112-2119. Available online at http://www.medscape.com/viewarticle/556743 through http://www.medscape.com. Accessed August 2009.

DeBusk, B. and Barclay, L. (2008 June 20). Severe Insulin Resistance Linked to Complications of Pregnancy and Birth CME. Medscape Medical News [On-line information]. Available online at http://www.medscape.com/viewarticle/576388 through http://www.medscape.com. Accessed August 2009.

Samuel T Olatunbosun, S. and Dagogo-Jack, S. (2008 August 13). Insulin Resistance. eMedicine [On-line information]. Available online at http://www.emedicine.com/med/TOPIC1173.HTM through http://www.emedicine.com. Accessed August 2009.

(2013 January). Insulin Resistance and Pre-Diabetes. National Diabetes Information Clearinghouse [On-line information]. Available online at http://diabetes.niddk.nih.gov/dm/pubs/insulinresistance/#diagnosed through http://diabetes.niddk.nih.gov. Accessed September 2013.

(©1995-2013) American Diabetes Association. Diabetes Basics, Lower Your Risk. Available online at http://www.diabetes.org/diabetes-basics/prevention/checkup-america/ through http://www.diabetes.org. Accessed September 2013.

Christine L. Snozek, PhD. Lab Tests Online adjunct board member.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

Reaven, G. (2004 June). The metabolic syndrome or the insulin resistance syndrome? Different names, different concepts, and different goals. Endocrinology and Metabolism Clinics V33 (2).

(2004 May). Insulin Resistance and Pre-Diabetes. National Diabetes Information Clearinghouse, NIH Publication No. 04-4893 [On-line information]. Available online at http://diabetes.niddk.nig.gov/dm/pubs/insulinresistance/ through http://diabetes.niddk.nig.gov.

(2002 August, Updated). Insulin Resistance Syndrome. Familydoctor.org [On-line information]. Available online at http://familydoctor.org/660.xml through http://familydoctor.org.

Levin, A. (2003 July). Silent Scourge of Insulin Resistance. NCRR Reporter, Cover Story [On-line news article]. Available online at http://www.ncrr.nih.gov/newspub/jul03rpt/sotries2.asp through http://www.ncrr.nih.gov.

Sadovsky, R. (2004 February 15). Best Way to Identify Patients with Insulin Resistance. American Family Physician, Tips from other Journals [On-line journal]. Available online at http://www.aafp.org/afp/20040215/tips/17.html through http://www.aafp.org.

Sadovsky, R. (2004 June 15). Metabolic Markers Predict Insulin Resistance. American Family Physician, Tips from other Journals [On-line journal]. Available online at http://www.aafp.org/afp/20040615/tips/9.html through http://www.aafp.org.

(2008 December). Insulin Resistance May Hasten Diabetes Progression in Certain Patients. Medscape from Reuters Health Information [On-line information]. Available online at http://www.medscape.com/viewarticle/568888 through http://www.medscape.com. Accessed August 2009.

Jeppesen, J. et. al. (2007 May 29). Insulin Resistance, the Metabolic Syndrome, and Risk of Incident Cardiovascular Disease [On-line information]. Medscape from J Am Coll Cardiol. 2007;49(21):2112-2119. Available online at http://www.medscape.com/viewarticle/556743 through http://www.medscape.com. Accessed August 2009.

DeBusk, B. and Barclay, L. (2008 June 20). Severe Insulin Resistance Linked to Complications of Pregnancy and Birth CME. Medscape Medical News [On-line information]. Available online at http://www.medscape.com/viewarticle/576388 through http://www.medscape.com. Accessed August 2009.

Samuel T Olatunbosun, S. and Dagogo-Jack, S. (2008 August 13). Insulin Resistance. eMedicine [On-line information]. Available online at http://www.emedicine.com/med/TOPIC1173.HTM through http://www.emedicine.com. Accessed August 2009.

(2006 August). Insulin Resistance and Pre-Diabetes. National Diabetes Information Clearinghouse [On-line information]. Available online at http://diabetes.niddk.nih.gov/dm/pubs/insulinresistance/ through http://diabetes.niddk.nih.gov. Accessed August 2009.

(Released December 12, 2009) Homeostatic (HOMA) Calculator. University of Oxford, Diabetes Trial Unit. Available online at http://www.dtu.ox.ac.uk/index.php?maindoc=/homa/index.php through http://www.dtu.ox.ac.uk. Accessed September 2009.