The most alcohol-sensitive liver enzyme — also a sensitive marker of oxidative stress and bile duct issues.
GGT (gamma-glutamyl transferase) is involved in glutathione metabolism and amino acid transport across cell membranes. It's notably elevated by alcohol, biliary tract disease, NAFLD, and oxidative stress.
GGT is the most sensitive routine liver enzyme to recent alcohol intake — often the first to budge after a heavy weekend. It's also independently predictive of cardiovascular and all-cause mortality even within "normal" lab range, making it useful as an oxidative stress proxy.
GGT is influenced by: alcohol intake (huge — even moderate use raises it), biliary obstruction or disease, NAFLD, oxidative stress and inflammation, smoking, certain medications (statins, some anticonvulsants), and pharmacologic agents — alcohol cessation drops it within 2–4 weeks; antioxidant repletion may modestly lower; weight loss reduces it via NAFLD improvement.
Useful as a discrete oxidative stress / hepatic resilience marker. If elevated despite no alcohol use, investigate biliary causes with your provider. On GLP-1s expect modest reductions alongside ALT. Track quarterly during major dietary or alcohol behavior change to validate impact.
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Start tracking →Informational only — not medical advice. Reference ranges vary by lab and individual context. Work with a licensed provider to interpret your specific results.