Liver Function

ALT (Alanine Aminotransferase) — What Your Blood Test Result Means

ScanHealth Learn Liver Function ALT (Alanine Aminotransferase)

Your Liver Damage Detector

ALT is an enzyme that lives inside your liver cells. When liver cells are damaged, ALT leaks into your blood—like water leaking from a cracked pipe. The more damage, the higher the ALT. It's the most specific marker for liver cell injury.

What is ALT (Alanine Aminotransferase)?

ALT is an enzyme found primarily in liver cells (hepatocytes). Unlike AST, which is found in many organs, ALT is quite specific to the liver. Elevated ALT = liver cells are being damaged.

What High ALT (Alanine Aminotransferase) Means

Your liver cells are being damaged and leaking this enzyme. Could be from fatty liver, alcohol, medications (like acetaminophen), hepatitis, or even intense exercise. Mildly elevated ALT is extremely common in the modern world—often from fatty liver disease.

Common symptoms:

Often asymptomatic (silent liver damage) · Fatigue · Right upper abdominal discomfort · Nausea · Jaundice (yellow skin/eyes) if severe · Dark urine

What Low ALT (Alanine Aminotransferase) Means

Not typically concerning. Low ALT is normal.

Common symptoms:

Not typically significant

Why It Matters

When normal:

Most specific marker for liver cell damage

Early detection of fatty liver disease

Monitors medication effects on liver

Guides treatment decisions

Risks if abnormal:

Fatty liver progressing to fibrosis and cirrhosis

Drug-induced liver injury

Viral hepatitis

Alcohol-related liver disease

What Can Cause Abnormal Levels?

Non-Alcoholic Fatty Liver Disease (NAFLD)

60% likely

The #1 cause of elevated ALT worldwide. Fat accumulation in liver cells causes inflammation and damage. Linked to obesity, insulin resistance, and metabolic syndrome.

Alcohol-Related Liver Injury (if applicable)

45% likely

Alcohol is directly toxic to liver cells. Even moderate consumption can elevate ALT in susceptible individuals.

Medications

Acetaminophen (Tylenol), statins, NSAIDs, antibiotics, and many others can cause liver cell injury.

Viral Hepatitis (B or C)

Chronic viral hepatitis causes ongoing liver inflammation and ALT elevation.

Intense Exercise

Heavy weightlifting or endurance exercise can transiently raise ALT.

What You Can Do

Reduce processed foods, sugar, and refined carbs

Impact: Addresses the most common cause (fatty liver) \u00B7 Timeline: 4-8 weeks

Coffee: 2-3 cups daily

Impact: Proven liver-protective effects, reduces ALT \u00B7 Timeline: 4-8 weeks

Limit or eliminate alcohol (if applicable)

Impact: Removes direct liver toxin \u00B7 Timeline: 2-4 weeks

If lifestyle changes aren't enough:

Lose 5-10% body weight if overweight

Impact: Can normalize ALT in fatty liver \u00B7 Timeline: 3-6 months

NAC (N-Acetyl Cysteine): 600mg twice daily

Impact: Supports liver glutathione and detoxification \u00B7 Timeline: 4-8 weeks

Regular exercise: 150+ min/week moderate intensity

Impact: Reduces liver fat even without weight loss \u00B7 Timeline: 4-8 weeks

Recommended retest: 4-8 weeks if elevated; 6-12 months if normal

Related Markers

ast alp ggt bilirubin_total albumin globulin
Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice. Always consult your doctor for diagnosis and treatment.

Got your blood test report?

Upload your PDF and understand ALL your markers in 2 minutes. Plain language. Traffic light status. No medical jargon.

Analyze My Report — Free

First report is free. No credit card needed.

Browse all markers