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Organ Function
ALT
Alanine aminotransferase — a liver enzyme that leaks into the blood when liver cells are damaged.
Optimal Range
< 25 U/L (optimal) · < 40 U/L (lab range)
Why It Matters
ALT is a sensitive marker for liver inflammation and metabolic dysfunction. Even mildly elevated levels are associated with non-alcoholic fatty liver disease (NAFLD), which affects up to 30% of adults and accelerates metabolic aging.