Gamma GT

July 21, 2020

What is Gamma GT?

Gamma-glutamyl transferase or Gamma GT (GGT) is an enzyme found predominantly in the liver. The blood level of GGT increases if the liver becomes injured or if the bile ducts become obstructed affecting the flow of bile. Therefore, GGT is a good biomarker for detecting liver disease and bile duct injury.[1]

Why take a Gamma GT blood test?

Gamma-glutamyltransferase is a good biomarker for detecting liver disease, especially alcohol-related liver disease. You may require a GGT test if you are displaying symptoms of liver injury. It can also help to identify why the concentration of alkaline phosphatase (ALP) may be increased. For example, if both ALP and GGT are raised then this is indicative of some liver disease or disease of the bile duct. Whereas a raised ALP level alone usually indicates bone disease.[1]

You can test your Gamma GT levels by purchasing a simple at-home finger prick test kit which is then analysed at an accredited lab. Forth offers a number of blood tests which include Gamma GT such as a liver function test which can be purchased for just £39.00.

What function does Gamma GT have in the body?

Gamma-glutamyl transferase is found in cell membranes in many tissues such as kidneys, bile ducts, brain and gallbladder. It helps to move amino acids across the cell membrane.

GGT is also a fundamental part of the GGT cycle which is involved in the production and metabolism of glutathione.

When we take enzyme-inducing drugs such as barbiturates, the levels of GGT in the liver are increased. Furthermore, individuals who drink chronic amounts of alcohol have increased GGT levels.[2]

How do changes in Gamma GT affect health and wellbeing?

Because increased levels of GGT are often caused by liver injury or damage, then the symptoms of this condition can affect your everyday life. The higher the concentration of GGT in the blood, the more extensive the liver damage is.

If excessive alcohol consumption is to blame, there may be underlying causes for drinking which should be addressed. Alcohol affects our mental ability to operate machinery, drive and carry out simple tasks. Therefore, it is essential not to drink alcohol if you are doing any of these activities. Furthermore, symptoms such as severe fatigue, stomach pain and jaundice can all severely affect your quality of life.

Some research has shown GGT levels may be predictive of chronic conditions like cardiovascular disease, type II diabetes and heart failure. Several studies have shown that GGT levels have been increasing in certain populations over the last three decades, possibly due to increased exposure to environmental chemicals as well as iron overload. [3]

If you are worried about your liver function or just want to check where you fall on the range, you can test your Gamma GT level with a simple at-home blood test.

What can cause Gamma GT to change?

There are several factors which can cause GGT levels to rise, including:

  • Liver injury
    • Consuming too much alcohol
    • Hepatitis
    • Reduced blood flow to the liver
    • Liver tumours
    • Cirrhosis
    • Fatty liver disease
  • Heart failure
  • Diabetes
  • Pancreatitis

An increased GGT and ALP level can indicate bone disease.


What are the most common symptoms of liver damage?

Increased GGT levels usually mean something is happening to your liver, although it can’t tell you specifically what. Liver damage can be a reason for liver damage, especially if you drink large amounts of alcohol.

Common symptoms associated with liver damage are:

  • Feeling tired and weak all or most of the time
  • Reduced appetite
  • Loss of libido
  • Jaundice (yellowing of the skin and whites of the eyes
  • Itchy skin
  • Nausea and/or vomiting[4]

GGT is sensitive and it is possible not to experience any symptoms when levels are raised. Equally, GGT levels can be raised at the same time as other liver enzymes which may help to establish a cause.

How to keep GGT in the healthy range

Although liver damage is a serious problem and can cause other health complications, it can be reversible if the damage isn’t too severe. The best ways to begin lowering GGT levels are to quit smoking, quit drinking alcohol and lose weight.

In the developed world, alcohol consumption is one of three leading causes of liver disease. Therefore, limiting alcohol intake is key to keeping your liver healthy. Government guidelines state the public should not regularly drink more than 14 units of alcohol per week. 14 units could be:

  • 6 pints of 4% beer
  • 6 glasses of 13% wine
  • 14 25ml shots of 40% spirits

You should also spread your units evenly over the course of the week rather than saving them up. You should also try to incorporate some alcohol-free days into the week, too to help your liver recover.

A diet high in natural foods such as fruit and vegetables has been linked to reduced blood GGT levels. These foods are a good source of vitamins, minerals and fibre, but they are also rich in antioxidants which have protective properties against DNA cell damage caused by high GGT levels. [5]

Being overweight and obese can increase the risk of fatty liver disease and so exercise is a good way to help lose weight. Exercise has many beneficial effects on both physical and psychological health. Physical activity reduces the fat in the liver and at the same times improves both cardiovascular and respiratory health. [6]

- Health scores calculated



[1] Lab Tests Online. (2016). GGT Test. Available at:

[2] Goldberg, D, M. (1980). Structural, Functional, and Clinical Aspects of Gamma-Glutamyl Transferase. CRC Crit Rev Clin Lab Sci: 12(1), pp 1-58.

[3] Koenig, G and Seneff, S. (2015). Gamma-Glutamyltransferase: A Predictive Biomarker of Cellular Antioxidant Inadequacy and Disease Risk. Disease Markers.

[4] National Health Service. (2017).  Liver Disease. Available at:

[5] Nanri, H., Hara, M and Tanaka, K. (2015). Dietary Patterns and Serum Gamma-Glutamyl Transferase in Japanese Men and Women. Journal of Epidemiology:25(5), pp 378-386.

[6] Smart, N, A., King, N., McFarlane, R., Graham, P, L and Dieberg, G. (2016). Effect of Exercise Training on Liver Function in Adults Who Are Overweight or Exhibit Fatty Liver Disease: A Systematic Review and Meta-Analysis. British Journal of Sports Medicine: 0, pp 1-11.

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This information has been medically reviewed by Dr Nicky Keay

Nicola has extensive clinical and research experience in the fields of endocrinology and sport and exercise medicine. Nicky is a member of the Royal College of Physicians, Honorary Fellow in the Department of Sport and Exercise Sciences at Durham University and former Research Fellow at St. Thomas' Hospital.

Dr Nicky Keay

Dr Nicky Keay

BA, MA (Cantab), MB, BChir, MRCP.