Gamma-glutamyl transferase (GGT) is an enzyme found throughout the body, with the highest levels in the liver. GGT plays an important role in glutathione metabolism, which is vital for antioxidant defense. It helps transfer amino acids and peptides across cell membranes. Elevated GGT levels are often used as a marker to detect liver damage, especially bile duct obstructions and liver conditions related to alcohol use.
High GGT levels can be caused by: