GGT

Meta-analysis or review · Moderate effect · 12 studies linked

Studied in: NASH, Nondiabetic, Hp2-2, Adults

• Haptoglobin 2 Allele is Associated With Histologic Response to Vitamin E in Subjects With Nonalcoholic Steatohepatitis. (2019)
• Effect of vitamin E on cardiometabolic factors in paediatric metabolic dysfunction-associated steatotic liver disease: a systematic review with meta-analysis. (2025)
• Vitamin E for people with non-alcoholic fatty liver disease. (2024)
• Vitamin E supplementation in the treatment on nonalcoholic fatty liver disease (NAFLD): Evidence from an umbrella review of meta-analysis on randomized controlled trials. (2023)
• Efficacy of Off-Label Therapy for Non-alcoholic Fatty Liver Disease in Improving Non-invasive and Invasive Biomarkers: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials. (2022)
• Comparative efficacy of tocotrienol and tocopherol (vitamin E) on atherosclerotic cardiovascular diseases in humans. (2024)
• +6 more studies

Meta-analysis or review · Moderate effect · 9 studies linked

Studied in: NAFLD, Alcoholic liver disease, HCV, DILI

Cacciapuoti 2013 (zhong_2017 content): GGT reduction p<0.001 in 72 NAFLD patients over 6 months. GGT reflects both hepatocellular damage and oxidative stress (GGT is rate-limiting for extracellular GSH catabolism and cysteine recycling); reduction may reflect dual anti-inflammatory and antioxidant action.

• The therapeutic effect of silymarin in the treatment of nonalcoholic fatty disease: A meta-analysis (PRISMA) of randomized control trials. (2013)
• Effects of silymarin supplementation on liver and kidney functions: A systematic review and dose–response meta‐analysis (2024)
• Long-term safety and efficacy of a highly purified plant-based nutraceutical for improving clinical parameters of liver function in healthy participants: a randomized, double-blind, placebo-controlled (2025)
• Comparison of efficacy of folic acid and silymarin in the management of antiepileptic drug induced liver injury: a randomized clinical trial (2017)
• Free Radical-Scavenging, Anti-Inflammatory/Anti-Fibrotic and Hepatoprotective Actions of Taurine and Silymarin against CCl4 Induced Rat Liver Damage (2015)
• [Controlled study of the effect of silymarin on alcoholic liver disease]. (1992)
• +3 more studies

Meta-analysis or review · Small effect · 4 studies linked

Studied in: Adults, NASH, NAFLD

GGT reduction in NASH context; less studied than ALT/AST but directionally consistent; may reflect biliary/hepatic oxidative stress improvement

• Melatonin Ingestion Prevents Liver Damage and Improves Biomarkers of Renal Function Following a Maximal Exercise. (2023)
• The effects of melatonin therapy on the treatment of patients with Non-alcoholic steatohepatitis: A systematic review and Meta-analysis on clinical trial studies. (2021)
• The effect of melatonin supplementation on liver indices in patients with non-alcoholic fatty liver disease: A systematic review and meta-analysis of randomized clinical trials. (2020)
• Gonciarz M et al. (2013)

Meta-analysis or review · Small effect · 4 studies linked

Studied in: Healthy adults, Norwegian, Krill oil form

Rundblad 2018: GGT increased in krill oil arm vs control (p=0.014, 8 weeks). Not observed in fish arm at comparable LC n-3 dose. Baseline GGT within normal range; clinical significance of elevation uncertain. Mechanism unknown — possible hepatic phospholipid remodeling, free phospholipid load, or astaxanthin metabol...

• Krill Oil Has Different Effects on the Plasma Lipidome Compared with Fish Oil Following 30 Days of Supplementation in Healthy Women: A Randomized Controlled and Crossover Study. (2018)
• Beneficial effects of probiotic combination with omega-3 fatty acids in NAFLD: a randomized clinical study. (2018)
• Does intravenous fish oil benefit patients post-surgery? A meta-analysis of randomised controlled trials (2013)
• Zhang S, Gu Y, Meng G, et al. (2017)

Meta-analysis or review · 1 study linked

Studied in: NAFLD

• Microbiome and metabolome analyses reveal significant alterations of gut microbiota and bile acid metabolism in ETEC-challenged weaned piglets by dietary berberine supplementation. (2024)

Human trials · 3 studies linked

Studied in: NAFLD, Alcoholic liver disease, Adults, Middle East

GGT reduction consistent with ALT/AST hepatic pattern but fewer dedicated studies. Effect attributed to reduced hepatic oxidative stress and NF-κB-driven hepatocyte inflammation.

• The effects of zinc supplementation on metabolic profile and oxidative stress in overweight/obese patients with non-alcoholic fatty liver disease: A randomized, double-blind, placebo-controlled trial. (2020)
• Effects of Zinc Supplementation on Inflammatory Status and Nonalcoholic Steatohepatitis in Overweight or Obese Children: a Randomized Clinical Trial. (2024)
• The Effect of Zinc Supplementation on Steatosis Severity and Liver Function Enzymes in Overweight/Obese Patients with Mild to Moderate Non-alcoholic Fatty Liver Following Calorie-Restricted Diet: a Do (2020)

Human trials · Moderate effect · 1 study linked

Studied in: Alcoholic hepatitis, Acute liver failure, NAFLD, Adult

• PubMed 24793546

Human trials · 1 study linked

Studied in: Healthy adults

• Ubiquinol reduces gamma glutamyltransferase as a marker of oxidative stress in humans. (2014)

Human trials · 0 studies linked

This result is graded, but no study is linked to it yet. Treat it as unconfirmed.

Studied in: NAFLD masld, Overweight obese

Human trials · 2 studies linked

Studied in: Healthy, Overweight, Age 40 60

Grade corrected from A to B: single source RCT only.

• Safety and Metabolism of Long-term Administration of NIAGEN (Nicotinamide Riboside Chloride) in a Randomized, Double-Blind, Placebo-controlled Clinical Trial of Healthy Overweight Adults. (2019)
• Nicotinamide riboside and pterostilbene reduces markers of hepatic inflammation in NAFLD: A double-blind, placebo-controlled clinical trial. (2023)

1 study linked

Studied in: Female, General adult

GGT is a sensitive marker of hepatobiliary stress and alcohol use. No creatine-attributable elevation in pooled female safety data.

• Risk of Adverse Outcomes in Females Taking Oral Creatine Monohydrate: A Systematic Review and Meta-Analysis. (2020)

Human trials · 4 studies linked

Studied in: Melas, High dose

8 corpus studies. The only human signal is a safety AE (increase, not decrease). At standard supplemental doses, direction is unknown.

• Phase IV prospective clinical study to evaluate the effect of taurine on liver function in postsurgical adult patients requiring parenteral nutrition. (2014)
• Ursodeoxycholic acid for liver disease associated with cystic fibrosis: a double-blind multicenter trial. The Italian Group for the Study of Ursodeoxycholic Acid in Cystic Fibrosis. (1996)
• Effects of ursodeoxycholic acid and taurine on serum liver enzymes and bile acids in chronic hepatitis. (1990)
• [Acamprosate. From pharmacology to therapeutics]. (1990)

0 studies linked

This result is graded, but no study is linked to it yet. Treat it as unconfirmed.

Studied in: Adults

GGT not consistently reported in Mg RCTs; theoretical link through oxidative stress pathway only.