ALT and AST — Liver Enzymes
Alanine and aspartate transaminases leak into blood when liver cells are stressed. Mild persistent elevations are the most common signal of fatty liver disease.
Alanine and aspartate transaminases (ALT and AST) are enzymes that leak into the blood when liver cells are stressed, making them the most common early signal of liver injury. Mild persistent elevations are the most common signal of fatty liver disease, while an AST/ALT ratio > 2 with alcohol exposure suggests alcohol-related injury.
The biomarker
- Name: ALT + AST
- Units: U/L
- Standard reference range: ALT 7–55; AST 8–48 (varies by lab)
- Optimal range: ALT 7–20; AST 8–25
How to read your result
| Value | Interpretation |
|---|---|
| Normal | No action |
| Mild elevation 1–2x | Investigate fatty liver, weight, alcohol |
| 2–5x | Clinician follow-up |
| ≥ 5x | Urgent referral |
What moves the needle
- Diet. Reduce alcohol, refined carbs, ultrasugar.
- Weight. 5–10% loss often normalises ALT.
- Testing. Recheck in 3 months after lifestyle change.
- Movement. Daily Zone 2 cardio.
Why this test is worth asking for
- Mild persistent elevations are the most common early signal of fatty liver disease — caught before symptoms appear.
- The AST/ALT ratio adds context: a ratio > 2 with alcohol exposure points to alcohol-related injury rather than fatty liver.
- It appears on most basic panels, so the signal is often already in your records waiting to be read.
Related protocols
- Vitamin D — 25-Hydroxyvitamin D
- Vitamin B12 + Methylmalonic Acid (MMA)
- TSH, Free T3 and T4 — Thyroid Panel
Sources
AgeGen lab guides are educational only. We do not provide medical diagnosis, prescribe brands, or recommend specific doses. Talk to a licensed clinician before changing your supplement or medication routine.