AST

Companion liver enzyme to ALT — also rises with muscle damage. AST/ALT ratio gives etiology hints.

What AST Measures

AST is structurally related to ALT but found in more tissues (liver, heart, skeletal muscle, kidney, brain). Like ALT, it rises with hepatocyte damage but also rises with intense exercise (muscle release) — which can confuse interpretation in athletic users.

The AST/ALT ratio offers etiology hints: ratio >2 with elevation suggests alcohol or muscle origin; ratio <1 with elevation typically suggests viral hepatitis or NAFLD. In normal-range scenarios, the ratio is less informative.

What Affects This Biomarker

AST is influenced by: liver function, recent intense exercise (muscle release — can elevate AST 2–3× transiently), alcohol intake, muscle injury, statins (occasional rise), hemolysis (can falsely elevate), and most things that affect ALT.

In the Context of Peptide Protocols

Always interpret with ALT in context. If AST > ALT and the user trains intensely, repeat draw 3–5 days post-rest before assuming liver issue. On GLP-1s expect AST + ALT to fall together. On GH protocols, AST can rise transiently with intense training cycles — not a liver problem per se.

Peptides That Commonly Move AST

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