GGT (gamma-glutamyl transferase) is a liver enzyme that climbs with oxidative stress (cell damage from unstable oxygen). That stress comes from excess carbohydrates, processed food, vegetable oil or alcohol. It burns through glutathione, your master antioxidant. Once GGT rises above the lowest 25% to 35% of the normal range, the risk of type 2 diabetes, stroke, cancer and death rises with it.
About GGT (Oracle of Death or The final common Pathway) | Reverse Diabetes MD from Gurpreet Padda on Vimeo. Excess processed foods and carbohydrates can also lead to more liver damage. People don’t think about GGT when they think about health risks. But it could be called the “oracle of death” or “the final common pathway” because of how it predicts liver damage and the disease that follows. Gamma-glutamyl transferase (GGT) is an enzyme found in high amounts in the liver. It is elevated in diseases that damage the liver. GGT is a transferase. That is an enzyme that moves a part of one molecule to another. It moves gamma-glutamyl groups from molecules such as glutathione (GSH) to an acceptor. That acceptor may be any amino acid, a peptide, or water. GSH removes free radical toxins. It gives natural protection against harmful oxidative stress. The normal job of GGT is to rebuild glutathione, the body’s master antioxidant. GGT is the only enzyme of the GSH cycle that sits on the outer surface of the plasma membrane (the cell’s outer skin). It breaks down GSH outside the cell. That provides cysteine, the rate-limiting building block, so the cell can make new GSH inside. When GGT levels are above “low-normal” ranges, excess GGT can catabolize (degrade) GSH. That causes critical depletion of this antioxidant. When GSH runs low, oxidative stress and damage start to occur. This leads to a cycle of irreversible cell, tissue, and DNA damage. Organ function becomes severely impaired. Elevated GGT indicates that you are demanding more GSH. It shows there was not enough GSH in the system to handle an oxidative insult. During oxidative stress, GGT gene expression goes up. This is an adaptation to stress. Say you eat excess carbohydrates, processed foods, vegetable oil, alcohol, or other liver toxins. Then the liver can become insulin resistant. That results in a high insulin level. High insulin is a metabolic switch. It causes fat to build up in the liver. Hyperinsulinemia (excess insulin) drives insulin resistance, and insulin resistance encourages more hyperinsulinemia. As fat builds up in the liver, the liver gets more insulin resistant. At the same time it goes through more oxidative stress. That drains glutathione. Rising GGT shows the drain. GGT data was first collected by the smartest guys in the room (life insurance actuaries). They first measured it because it could mark alcohol abuse in life insurance applicants. The life insurance industry collected this data for many years. The result was biometric stratification of mortality risk. That means sorting people into risk-of-death groups by body measures. It is now central to how life insurers predict all causes of death. Palmier J., Dixon A., Lanzrath B. Leading Contributors to Mortality Risk in Life Insurance Applicants. Schaumburg, Ill, USA: Society of Actuaries; 2012. (Smalltalk Issue 38). Palmier J., Lanzrath B. J. Laboratory and biometric predictors of cancer-related mortality in an insured population. Journal of Insurance Medicine. 2012;43(3):162–168 In the past, elevated GGT has been associated with liver problems, most often from drinking too much alcohol. Other drugs that can raise GGT include barbiturates, phenytoin, anti-inflammatory drugs (including aspirin), St. John’s Wort, and kava. We now believe that elevated GGT is an early warning sign of other health risks. These include atherosclerosis, stroke, type 2 diabetes, kidney disease, cancer, metabolic syndrome (MetS), and all-cause mortality (death from any cause). GGT doesn’t have to be above a lab’s normal levels for risk to go up. When GGT levels pass the lowest 25% to 35% of normal population ranges, disease risks grow in step with GGT. This “dose-response” rise in GGT indicates a greater risk of future disease and death. That holds even when GGT levels are within “normal” ranges. Even high-normal GGT carries a significant rise in risk: Normal low
- < 9 U/l for women
- < 14 U/l for men
Moderately high with increased risk
- 18 U/L for women
- 28 U/L for men
High levels of normal with significant increase in risk
- >36 U/L for women
- >56 U/L for men
According to the National Institutes of Health, “GGT levels measured in the Framingham Offspring Study (FOS), only moderately elevated GGT, starting at levels just above population GGT medians, and often measured one or two decades in advance of disease endpoints or mortalities, established GGT as an early predictive marker of MetS, CVD, heart failure, and all-cause mortality.” Gamma-Glutamyltransferase: A Predictive Biomarker of Cellular Antioxidant Inadequacy and Disease Risk Gerald Koenig, Stephanie Seneff. Dis Markers. 2015; 2015: 818570. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4620378/ GGT predicts future death. In the general population, about 21% of men and 15.6% of women have elevated GGT. Elevated GGT, even within normal lab ranges, carries significant added risks. Patients with high-normal GGT have more than a 1.5-fold risk of dying from cardiovascular diseases. That is compared to people with low-normal GGT. Look at all-cause mortality. Elevated GGT in the upper fifth of the population gives a 2x higher risk for all-cause mortality (death from any cause). It gives a 1.7x higher risk of cardiovascular death, and a 2.3x higher risk for cancer and death. Now look at liver cancer. Elevated GGT in the upper fifth of the population (not even the top 1%) gives a 15 to 18 times higher risk of hepatic cancer and death from liver cancer. Hazard ratios According to Clinical Chemistry, “GGT above the reference category (GGT ≥9 U/L in women, ≥14 U/L in men) was significantly (P <0.001) associated with all-cause, cancer, hepatobiliary, and vascular mortalities.” Gamma Glutamyltransferase and Long-Term Survival: Is It Just the Liver? Lili Kazemi-Shirazi et al. DOI: 10.1373/clinchem.2006.081620 Published April 2007. http://clinchem.aaccjnls.org/content/53/5/940 High levels also raise the risk of atherogenic dyslipidemia (a blood fat pattern that builds plaque). It predicts coming heart disease. Dyslipidemia reflects insulin resistance. When your liver becomes insulin resistant, it will tend to cause visceral fat (the fat packed around your organs) to build up in your organs. Visceral fat buildup is most clearly seen as a larger waist than expected, or a “beer belly,” even a small one in women. Many people look slim, but they are TOFI (thin outside, fat inside). Dyslipidemia is a mix of high LDL, low HDL, high triglyceride, high particle count of LDL
- LDL:HDL Triglyceride:HDL LDL-P Oxidized LDL GGT
Most idiopathic or essential hypertension (high blood pressure with no known cause) is related to hyperinsulinemia. The extra insulin makes blood vessels stiff and thick. Reversing hypertension may be as simple as reducing insulin. GGT correlates with plaque forming in arteries (atherosclerotic plaque). That plaque is associated with an inflammatory disease, metainflammation. GGT activity also shows up in the same spot as oxidized LDL in the plaque, as seen below. Circulating Markers of Liver Function and Cardiovascular Disease Risk. Arterioscler Thromb Vasc Biol. 2015 Nov;35(11):2290-6. doi: 10.1161/ATVBAHA.115.305235. Epub 2015 May 14. https://www.ncbi.nlm.nih.gov/pubmed/25977566 Risk for future diabetes: If your BMI is low and your GGT is low, you have a baseline risk of 1.0. Say you have a low BMI below 25 and a high GGT (in the top quarter of the population). Then you have a 3x risk of diabetes within 3-5 years. Say you have a moderate-high BMI greater than 30 and a high GGT (in the top quarter of the population). Then you have a 15x risk of diabetes within 3-5 years. Say you have a high BMI greater than 35 and a high GGT (in the top quarter of the population). Then you have a 19x risk of diabetes within 3-5 years. Obesity is one factor that predicts future diabetes, but GGT may be more accurate. Once you adjust obesity for GGT, obesity doesn’t predict diabetes. GGT predicts diabetes better. That is because it shows liver insulin resistance and liver inflammation.
Our treatment protocols for elevated GGT encourage:
- Squeeze the fat out of the liver with either time-restricted feeding or fasting
- Cut out vegetable oil and take fish or krill omega-3 oil
- Switch to natural fats, such as butter and tallow
- Cut out processed foods, including refined grains and acellular carbohydrates
- Metformin to boost insulin sensitivity in the liver
- Drinking moderate to high amounts of coffee has been universally shown to reduce GGT
Related reading
Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP
Interventional pain physician, addiction medicine specialist and obesity medicine diplomate.
Licensed in Missouri and Illinois.
Last reviewed June 17, 2026
