GGT is a liver enzyme involved in the transport of amino acids and peptides into cells as well as glutathione metabolism. GGT is mainly found in liver cells and as such is extremely sensitive to alcohol use. Elevated GGT levels may be found in liver disease, alcoholism, obesity, bile-duct obstruction, cholangitis, and drug abuse. Decreased levels can be found in hypothyroidism, hypothalamic malfunction and very low levels of magnesium. Because both chronic alcohol consumption and obesity associated with metabolic abnormalities are increasing in Western societies, the concomitant occurrence of these factors is of considerable interest. In this scenario, advanced liver disease, including inflammation, fibrosis, cirrhosis, and liver cancer, may develop more rapidly. The determination of a normal serum GGT activity range needs to be reevaluated and adjusted to BMI to avoid wrong conclusions with respect to alcohol consumption.

GGT is an enzyme that metabolizes extracellular glutathione and can be induced by various xenobiotics, drugs, and ethanol. All these compounds, including free fatty acids and acetone, may also induce cytochrome P4502E1 (CYP2E1). GGT stands for gamma-glutamyl transpeptidase. Another liver test is called ALT.

GGT Level in the blood - test values - blood test for a man and woman

Normal Adult Female Range: 0 - 45 U/L
Normal Adult Male Range: 0 - 65 U/L
     Elevated GGT level can occur due to obesity.

Causes
GGT levels can be increased by alcohol phenytoin (Dilantin), an anti-seizure medication, and phenobarbitol, an antiseizure medication and sedative, and decreased by clofibrate, an anticholesterol drug, and birth control pills. High GGT levels are associated with liver diseases such as hepatitis, cirrhosis, liver tumors, and jaundice, myocardial infarction, pancreatic cancer and pancreatitis and viral infections such as Epstein-Barr, cytomegalovirus (CMV) and Reye's Syndrome.

High GGT blood test predicts heart disease

Serum gamma-glutamyltransferase predicts non-fatal myocardial infarction and fatal coronary heart disease among 28 838 middle-aged men and women.
Eur Heart J. 2006 Jun 13;
Serum gamma-glutamyltransferase (GGT) concentration may be involved in atherosclerosis. This study examined if serum GGT predicted coronary heart disease (CHD), especially differentiating non-fatal myocardial infarction (MI) and fatal CHD event, among the general population or participants with type-2 diabetes. Conclusion: This study suggests an independent mechanism linking serum GGT to coronary heart disease. Even though the strength of association appeared to be modest among all subjects, stronger associations were observed among subjects aged <60 and among alcohol drinkers. Especially, measurement of serum GGT among type-2 diabetics may be helpful to predict the future risk of CHD.
 

Fatty Liver and elevated GGT

Chronic alcohol consumption as well as overweight and obesity associated with insulin resistance and the metabolic syndrome are the major factors resulting in fatty liver. Alcoholic fatty liver as well as nonalcoholic fatty liver can progress to more advanced liver disease, including inflammation, cirrhosis, and liver cancer. From a public health perspective, the most successful approach to deal with these liver diseases is early detection and intervention instead of treating the complications of advanced liver disease. Early detection of fatty liver includes its noninvasive verification, mostly done by hepatic ultrasound, and identification of its cause, which includes the patient's history. Because it is sometimes difficult to obtain an exact history of alcohol consumption, laboratory markers of chronic alcohol misuse have been established and are frequently used. One of the best markers for chronic alcohol consumption is serum {gamma}-glutamyl transferase (GGT), which has a relatively high sensitivity and specificity. Because measurement of this enzyme is easy and inexpensive, it has generally been used for early detection of chronic alcohol misuse. However, serum GGT activity loses its specificity for alcohol in more advanced liver disease because its activity is elevated in hepatic inflammation and more advanced liver disease regardless of the cause. Although chronic alcohol consumption is the most frequent cause of elevated serum GGT activity, an increased activity of this enzyme can also be observed under medical treatment and in acute pancreatitis, myocardial infarction, hyperthyroidism, anorexia nervosa, certain muscle diseases, neurological disorders, porphyria cutanea tarda, and some malignancies. Recently, non alcoholic fatty liver disease has become an important issue in the United States and Europe because of the striking increase in overweight and obese persons in these countries. Because these persons frequently also have increased GGT activities, a differentiation between AFL and NAFL on the basis of serum GGT activity is difficult. Furthermore, overweight is sometimes the result of chronic alcohol ingestion, and FL often results from both ethanol consumption and metabolic abnormalities. Serum GGT activity is influenced not only by the amount of alcohol consumed but also by body mass index (BMI) and sex.

Q. I have been taking Red Yeast Rice to lower my cholesterol over the last two years (taken with Niacin and CoQ10). My medical physician has told me that this works on your liver in the same exact way that statin drugs do, and that I should be aware of that, even though it is a natural alternative to conventional cholesterol treatments such as Lipitor. My question is then, does taking Red Yeast on Rice affect the liver to raise GGT levels? A recent blood test showed good numbers in every other category, except elevated GGT level, which was 119 (range should be < 62). I am active and play in a men’s Basketball league. I have not eaten red meat for over 30 years, and mostly eat a lacto-avo vegetarian natural food diet. I do not have any other issues health-wise, and do not take any other substances other than the Red Yeast. I have not had alcoholic beverages for over 32 years (aside from an occasional non-alcoholic beer for taste). I know from your article that high GGT levels are primarily the result of alcoholism, so I can’t figure what else would be doing this aside from the Red Yeast.
   A. It is possible that red yeast rice could lead to elevated ggt level in some people. The best way to find out in your case is to stop the red yeast rice for a month or so and then retest the GGT liver enzyme level to see if it goes down. To confirm, you could restart the red yeast rice supplement and then retest a couple of months later to see if the GGT liver enzyme level goes up again.

Q. Hi, wanted to know is it possible for elevated GGT enzyme levels to go down on its own if alcohol consumption is completely stopped?
   A. If this was due to alcohol overuse, and the alcohol is stopped, then there is every reason to expect it to go down.

Q. I'm writing in regards to an article about GGT levels. I recently had blood work done and was told my GGT levels were higher than normal. I am wine drinker and have a good feeling it was from my alcohol consumption. On average, how long does it take for GGT levels to start dropping if alcohol consumption is stopped?
   A. It can take a few days or a few weeks for GGT levels to drop depending on how long you have been drinking alcohol, how much alcohol you have been drinking, the type of alcohol, the general health of your liver and body, other medicines or supplements you may be taking, (ex" acetaminophen can damage the liver), your age, diet, etc.
      Q. Thank you very much for the quick reply back. I started out with a GGT level of 75 last week and hit 61 this week on the GGT. I really appreciated this GGT information article because it was one of the deciding factors in me ending drinking.

Q. I had a high GGT count on my latest liver test blood work up in October 2007. I had been taking Prexige since January 2007 until yesterday when I tried to refill the prescription and was told it was taken off the market-I was told it could cause liver failure or damage. If this is so and I have stopped this med would the count go back down again?
   A. Prexige (lumiracoxib), by Novartis, had been approved in 2003 by the Medicines and Healthcare products Regulatory Agency (MHRA in the United Kingdom. Prexige was approved for symptomatic relief of osteoarthritis and* short-term relief of moderate to severe acute pain associated with primary dysmenorrhea, dental surgery, and orthopedic surgery. The potential damage to the liver from Prexige, or most medicines that can harm the liver, depends on each person's unique biochemistry, alcohol use, concurrent use of tylenol, stating drugs, or other drugs that harm the liver, dosage, frequency of use, and other factors. We don't have much experience with Prexige so we can't say how long the GGT levels will stay up.

Q. I have read your article on elevated GGT and it contains more information on GGT that I have heard from my personal physicians in 3 years. I have a GGT of 186, elevated. I am 6'33'' and 190 pounds, do not drink alcohol excessively, and have not had an alcoholic drink in 2008. I have been tested for fatty liver, hepatitis, and various other things - all proven to be negative. I eat well, exercise regularly and live a healthy lifestyle. My doctor wants to do a liver biopsy. Is it possible to have a genetically high GGT? Is it possible that a high GGT will have no underlying cause? Is it possible to have a high GGT and have nothing to worry about?
   A. It depends on how high the GGT level is. If it is slightly or moderately high, it is possible that there could be no serious underlying disease. If the GGT level is very high, then it is of concern and there could be a serious underlying condition. It also depends on how the GGT level is changing over time. There are no easy answers.
      Q. My GGT is 186 - and has been consistently 160-190 over the last several years.
         A. One has to take into account all other liver enzyme values, other blood tests, the physical exam, and overall medical health, diet, medications used, and not just rely on one out of range blood study.

Q. Can you summarize the liver test ggt and in which conditions there could be a high level of ggt in the blood?
   A. GGT blood levels may be elevated due to liver disease, hepatitis, gallstones, diabetes, pancreatic disease, kidney failure, alcohol misuse, certain prescription drugs, certain herbs and supplements or taking very high amounts of supplements, or a tumor.

Q. I have had some lab work done and all areas were "in range" except GGT level which was 115, very high. I am female, 61 years old, drink an occasional red wine, and am 75 lbs. overweight. I exercise daily and am trying to lose weight. In your opinion, if I drop some weight, will the GGT level drop? I have no other symptoms of liver problems.
   A. It is not possible for us to know if the level of GGT will drop with weight loss, but is is a possibility if there are no other causes of liver harm.

Q. I recently had a GGT blood test and the results were 192. I do not drink alcohol ever, I am on some medications but the medications I'm on is medications I have been on for years and my liver test always come back normal. A few months ago my AST and ALT have been slightly elevated but this is the first time my GGT has been elevated. Yesterday I had a yearly appointment with my GYN and when I asked her about the test and results she gave me a horrible look and said I needed to see a gastro dr. asap. The last few weeks my stomach becomes distended any time I eat something whether it is a cracker or a regular meal. I am also having terrible stomach pain, nausea, and severe fatigue. I did schedule an appointment with a gastro dr. for next Thursday (which was the earliest appointment they had). I have read your information but I am really nervous, do I have cause to be? I would appreciate any advise you can offer.
   A. It is not possible for me to know your health condition without a full medical history, exam, review of all blood studies and medication use. I wish you optimal health and hope the GGT level returns to normal.

I read your article (and the Q & A sessions) on GGT with great interest - most definitely more informative than any information provided by GPs. I am wondering exactly how a highly elevated GGT level affects metabolism.
   It's difficult to say since the word metabolism has such a broad definition. Much depends on the cause of GGT elevation.

My husband and I recently had home physicals for insurance purposes and my GGT was elevated to 140. I am a 56 yr old female 15-20 lbs overweight, whose mom died from pancreatic cancer. I had my gallbladder removed in 1998. I have several things going on. I'm taking approx (2-6) Tylenol / Advil a day for what may be fibromyalgia (am seeing a physiatrist) who had prescribed Flexaril for muscle and joint pain and I also suffer from IBS and interstitial cystitis which I've been taking Ditropan for 20 years. The last blood done with my yearly physical showed elevated SED rate. I do have 2-3 glasses of wine 4-5 times a week. Does this elevated level indicate certainly liver damage or just an increase of the enzyme in the blood?
    It is not possible for me to know the cause of the elevated GGT since many factors are involved, but it is well known that acetaminophen can cause liver damage.

 Recently I have a blood test, I am 35 years old male. My GGT higher than normal, which is about 105. Doctor advised me to take supplement Essentiale fort. I was wondering if I stop drinking, is there any possible my liver can go back to normal and healthy?
    Reducing alcohol intake can improve liver health.

I have been enjoying reading your website. I recently requested a liver panel and the test done was a GGT. My number was 17. I’m 42 and I’m seeking direction on what other liver tests would be performed for somebody like me trying to find out why I suffer from severe hangovers (when I drink which is not very often at all), hangovers or feelings like one when I don’t drink and finally toxic inversion (performed healing therapies and ended up with more pain than before the treatment).
    Some people have a genetic predisposition to poor alcohol metabolism.

Thank you for your article about GGT. I have had raised GGT for an almost one year. No visible problems with liver by CT. No problem of myself. All started with increased levels of more the liver enzymes and my overweight (I am a good eater). After I changed from a fat to the slim guy, all enzymes went down, but ggt remains above the normal level (3.5 times more during first months; last level was twice the normal one about a month ago). My Dr. is very nervous about it and wanted to send me for a liver biopsy. I refused since there is no idea what is with the liver and she suppose I was just poisoned somehow. If I asked what would be seen by biopsy concerning poisoning, she sad that maybe nothing. I take drugs which should heal liver regularly. Serologic investigation did not prove any infection could be responsible for the problem. If you have any experience what could be my problem, please, just let me know briefly.
    Without examining and knowing the full history and blood results, it is not possible for me to make any suggestions. One has to evaluate the whole person and not rely exclusively on one blood study result to make decisions about diagnosis or treatment.

I was interested to read so much about GGT levels as I have had them for the last couple of years and don’t seem to be getting any answers form my physician as to what I can do to feel better. How can I lower the levels that are currently sitting at 195 IU/L. The highest they have been is 198 back in April. My ALT is 48 IU/L, all other proteins within normal range. I am a 44 year old woman, weight 77kgs. I have felt so tired and nauseated for so the last 10 months that I haven’t managed to exercise much. I have also had many “toxic times” when the only way to describe my body is toxic. My face swells, I’m nauseated, bloated and my abdomen is tender. I would really appreciate some advice on how to lower the levels and start feeling better.
    Sorry, but I am not able to provide individual advice.

I was reading your article on liver testing ggt blood test. While I have a question to ask you regarding my husbands ggt levels. He went to the doctor and his level was over 400, and the doctor told him he has nothing to worry about. After reading several questions on your page that doesn't seem to be true. He has never drunk any alcohol, or done any type of illegal drugs. Now he did take ibuprofen for several years because he was working out daily and he plays a lot of different sports, he very active. We also found out that he was allergic to ibuprofen after he had taken it for several years, he just stop taking it earlier this year. So since he had a bad allergic reaction to the ibuprofen, he was give a anti depression drug. We are very concern because the doctor is saying there is nothing wrong, but your article states other wise. Should we be worried since his levels are over 400, please help?
    Each case has to be evaluated on its own taking into account not only the level of a particular liver enzyme but what other test results are showing, and overall health review and medical exam.

I have had two GGT level run within a month period and the first was at 364 and the one yesterday was at 245. All of my other Liver tests are normal plus all the other lab profiles are normal. I do not drink or smoke and I am 48 years old and am not overweight and am in good health. Eight years ago I had the same thing happen with this same test and they did a liver biopsy and ultrasound tests and everything was normal. Any thoughts?
    I cannot provide individual advice but when evaluating the results of any lab test, one has to put it in perspective with the results of other tests, review of patient symptoms, and evaluation of a thorough medical exam.

I just turned 49, am normal weight and I've had elevated levels of GGT b/n 60 and 130 over the past few years. My run marathons and train a lot, drink minimal alcohol and my AST and ALT are just over the normal ranges (by 2 or 3 numbers) or normal based on several tests over the past 5 years. No other enzymes have been out of range. I had an ultrasound that was negative for fatty liver. Other than a baby aspirin a day I don't take anything other than noted below. I took Lamisil for toe nail fungus a few years ago. Could that have a lasting affect? When I was on it, my ALT and AST were normal but I was never tested for GGT. I was also taking Coenzyme Q10 for a while and during my last test this past October. Is there are research that CoQ10 causes elevated liver enzymes? I've read that distance running can cause elevated enzyme levels due to muscle breakdown but the info. I read did not say how long the effect lasts for. Any suggestion on how long I should refrain from running before getting retested?
    It is unlikely that the use of Lamisil that was stopped several years ago would still have an effect on the liver. The influence of high doses of CoQ10 on liver enzymes is not clear at this time but most likely this supplement does not play a major role although it is possible there could be some people who have unusual reactions.

Thanks for your article its very interesting. I recently had tests done and was told my GGT result is high at 60. I am a 45 year old male living in Australia where they state “normal” levels are 0-49 for adults. Any idea why the accepted norms are different and should I be concerned at levels of 60 when all other liver related tests are in the normal ranges?
    I don't know how they test and evaluate levels in Australia. I prefer not to rely on the results of an isolated blood level of any enzyme, hormone, nutrient, mineral, vitamin, etc in terms of a diagnosis or treatment plan. One has to evaluate the whole person and make a decision on treatment based on the whole range of history, symptoms, physical exam, and results of other routine blood studies.