What It Measures
ALT measures the level of the enzyme alanine aminotransferase in your blood. Since this enzyme is concentrated in liver cells, elevated blood levels indicate liver cell damage or inflammation — essentially, it tells you how much your liver is being stressed or injured.
Alanine aminotransferase (ALT) is an enzyme found predominantly in liver cells that plays a key role in amino acid metabolism. When liver cells are damaged or inflamed, ALT leaks into the bloodstream, making it one of the most specific and sensitive markers of liver injury and overall liver health.
Current Value
What High Means
Elevated ALT indicates liver cell damage or inflammation. Common causes include non-alcoholic fatty liver disease (NAFLD), alcohol-related liver disease, viral hepatitis (B and C), medication toxicity (acetaminophen, statins, NSAIDs), autoimmune hepatitis, and metabolic dysfunction. Mildly elevated ALT (1-3x upper limit) often reflects insulin resistance and fatty liver. Markedly elevated ALT (>10x) suggests acute hepatitis, drug-induced liver injury, or ischemic hepatitis. Chronic mild elevation is strongly associated with metabolic syndrome and increased cardiovascular mortality.
Possible Symptoms
Mildly elevated ALT is often asymptomatic. With significant elevation: fatigue, right upper quadrant abdominal pain, nausea, loss of appetite, jaundice (yellowing of skin/eyes), dark urine, pale stools, itching, abdominal swelling, and unexplained weight loss.
What Low Means
Very low ALT levels (below 10 U/L) may indicate a vitamin B6 (pyridoxine) deficiency, since B6 is a cofactor for ALT. Extremely low levels have also been associated with frailty, sarcopenia, and increased all-cause mortality in elderly populations, likely reflecting decreased liver functional mass or overall poor nutritional status.
Possible Symptoms
Very low ALT is typically asymptomatic but may accompany signs of B6 deficiency (peripheral neuropathy, dermatitis, cracked lips, confusion) or general frailty, muscle wasting, and fatigue in older adults.
Risk Factors
Non-alcoholic fatty liver disease (NAFLD), metabolic syndrome, type 2 diabetes, obesity, excessive alcohol consumption, viral hepatitis B and C, autoimmune hepatitis, drug-induced liver injury, hemochromatosis, Wilson's disease, celiac disease, cardiovascular disease, and insulin resistance.
Actionable Advice
Supplements
- •Milk Thistle (Silymarin)
- •N-Acetyl Cysteine (NAC)
- •Vitamin B6 (Pyridoxine)
- •Omega-3 Fatty Acids
- •Vitamin E (for NAFLD)
- •Alpha Lipoic Acid
- •Berberine
- •Turmeric/Curcumin
- •Phosphatidylcholine
Diet & Lifestyle
- •Limit or eliminate alcohol consumption
- •Maintain a healthy weight — even 5-10% weight loss significantly reduces liver fat
- •Follow a Mediterranean-style diet rich in vegetables, healthy fats, and lean protein
- •Exercise regularly — both aerobic (150+ min/week) and resistance training reduce liver fat
- •Avoid unnecessary medications and acetaminophen overuse
- •Minimize fructose and refined sugar intake — major drivers of fatty liver
- •Stay hydrated and limit processed food consumption
- •Get tested for hepatitis B and C if you have risk factors
- •Monitor and manage insulin resistance and blood sugar levels
- •Avoid rapid weight loss which can paradoxically worsen liver inflammation
Ask AI
Ask questions about your ALT results, trends, and what you can do to optimize.
Historical Trend
Related Biomarkers
Resources & Studies
All Readings
| Date | Value | Change |
|---|---|---|
| 2026-01-28 | 24 U/L | -10.0 |
| 2025-08-25 | 34 U/L | -5.0 |
| 2025-06-27 | 39 U/L | — |