Liver Enzymes (ALT, AST, GGT)
ALT and AST are enzymes released when liver cells are stressed or damaged, in U/L. Optimal range: Healthy ALT: men 29-33 U/L, women 19-25 U/L (assess above these, not the lab's looser range).
What it measures
ALT and AST are enzymes released when liver cells are stressed or damaged, in U/L. GGT rises with bile-duct stress and alcohol use. Together they screen for fatty liver and liver injury.
Why it matters
Non-alcoholic fatty liver disease affects roughly a third of adults and predicts diabetes and cardiovascular disease. True healthy ALT is far lower than many lab reference ranges suggest.
Optimal ranges
Sourced targets, not just lab reference ranges. Lab ranges describe the population; these describe where the evidence says you want to be.
| Range | Context |
|---|---|
| Healthy ALT: men 29-33 U/L, women 19-25 U/L (assess above these, not the lab's looser range) | American College of Gastroenterology true-healthy ALT thresholds (Kwo et al., Am J Gastroenterol 2017); conventional lab cutoffs near 40 U/L are considered too permissive. |
How to improve it
- 1
Lose visceral fat; fatty liver is the most common cause of mild elevation
- 2
Cut alcohol and fructose
- 3
Exercise regularly
- 4
Review medications and supplements with your doctor
Connected to
Goals
Longevity Lab Report
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Educational information, not medical advice. Talk to your doctor before acting on any biomarker result.