GGT
The optimal range for GGT (Gamma-Glutamyl Transferase) is commonly cited as <25 U/L (men) · <20 U/L (women), tighter than the standard lab reference range of Men: 8–61 U/L · Women: 5–36 U/L. The most alcohol-sensitive liver enzyme - also a sensitive marker of oxidative stress and bile duct issues.
How GGT ranges relate
The standard lab range vs the optimization-focused target. Illustrative trajectory shows what a 12-week improvement pattern looks like — not real user data.
What GGT Measures
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.
What Affects This Biomarker
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.
In the Context of Peptide Protocols
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.
Peptides That Commonly Move GGT
Conditions That Track GGT
Frequently Asked Questions
What does GGT measure?
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.
What is the optimal range for GGT?
The optimal range for GGT is commonly cited as <25 U/L (men) · <20 U/L (women). The standard lab reference range is Men: 8–61 U/L · Women: 5–36 U/L.
What affects GGT levels?
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.
Where This Fits in Your Panel
GGT is one marker on a fuller panel. The Peptide Blood Work Checklist lays out the complete baseline panel, what to add by protocol type, and when to retest.
See the full blood work checklist →Upload any lab PDF and MyProtocolStack maps your values to GGT and 40+ other biomarkers. StackAI interprets the trend in context of your protocol.
Start tracking →Last reviewed: June 2026
Informational only - not medical advice. Reference ranges vary by lab and individual context. Work with a licensed provider to interpret your specific results.