AST (Aspartate Aminotransferase)

Enzyme found in liver and other tissues

21/22Providers

Liver FunctionCategory

10-40 U/LReference

Widely Available

21 of 22 providers

Reference Range

10-40 U/L

What is AST (Aspartate Aminotransferase)?

AST (Aspartate Aminotransferase) is an enzyme found in multiple tissues including liver, heart muscle, skeletal muscle, kidneys, and red blood cells. When these tissues are damaged, AST is released into the bloodstream. While less liver-specific than ALT, AST is valuable when interpreted alongside ALT and other markers.

The AST/ALT ratio is particularly diagnostic:A ratio less than 1 (AST lower than ALT) typically indicates non-alcoholic fatty liver disease, while a ratio greater than 2 suggests alcoholic liver disease or advanced cirrhosis. AST is also crucial for detecting heart damage (elevated after heart attacks), muscle injury (rhabdomyolysis), and hemolysis (red blood cell breakdown).

AST exists in two forms:cytoplasmic AST (released with mild injury) and mitochondrial AST (released with severe injury). Very high AST levels (>1000 U/L) suggest acute hepatocellular necrosis from causes like viral hepatitis, drug toxicity, or ischemic injury. Like ALT, optimal AST levels for longevity are lower than conventional reference ranges.

Why AST Matters Beyond the Liver

Differential diagnosis:AST/ALT ratio helps distinguish alcoholic from non-alcoholic liver disease, and acute from chronic injury
Multi-organ damage detection:Unlike ALT, elevated AST can indicate heart attack, muscle breakdown, or hemolysis, not just liver disease
Severity indicator:Very high AST (>10x upper limit) indicates severe acute injury requiring urgent intervention
Fibrosis progression:Rising AST/ALT ratio over time suggests advancing liver fibrosis or cirrhosis
Metabolic health marker:Like ALT, elevated AST in the "high-normal"range correlates with insulin resistance and cardiovascular risk

Optimal vs Standard Ranges

Range Type	Level	Significance
Optimal (Longevity)	Men:<25 U/L, Women:<20 U/L	Associated with optimal metabolic health and lowest cardiovascular risk. Studies show these levels correlate with reduced mortality and better long-term health outcomes. Maintain AST/ALT ratio between 0.8-1.3 for optimal health.
Borderline Elevated	Men:25-40 U/L, Women:20-35 U/L	Often within standard reference range but may indicate early metabolic dysfunction, mild fatty liver, or subclinical muscle/heart issues. Check AST/ALT ratio and consider lifestyle modifications. Retest in 3-6 months.
Moderately Elevated	40-150 U/L	Indicates tissue damage requiring investigation. Check ALT, CK (creatine kinase for muscle), troponin (for heart), and liver imaging. If AST/ALT ratio >2, consider alcohol use or advanced liver disease. If AST elevated alone with normal ALT, consider heart or muscle source.
Severely Elevated	>150 U/L	Indicates significant acute injury. Levels >1000 U/L suggest acute hepatitis, drug-induced liver injury, ischemic hepatitis, or myocardial infarction. Requires urgent medical evaluation, comprehensive workup including troponin, CK, hepatitis panel, and imaging. Very high levels (>10,000) indicate massive tissue necrosis.

Standard lab range: 10-40 U/L

How to Optimize AST (Aspartate Aminotransferase)

1. Address Underlying Liver Disease

Weight loss for NAFLD:7-10% body weight reduction if overweight (same as ALT)

Alcohol cessation:If AST/ALT ratio >2, eliminate alcohol completely for 3-6 months and retest

Treat viral hepatitis:Antiviral therapy for Hepatitis B or C can normalize AST

Mediterranean diet:Rich in olive oil, fish, vegetables;reduces liver inflammation

Coffee consumption:2-3 cups daily associated with lower AST and reduced fibrosis risk

2. Optimize Cardiovascular and Muscle Health

If AST elevated with normal ALT, consider cardiac sources:Check troponin, ECG, and consider cardiology referral if chest pain, dyspnea, or cardiac risk factors

Manage muscle injury:If CK also elevated, identify cause (strenuous exercise, statins, rhabdomyolysis). Hydrate well and avoid intense exercise until normalized

Statin-induced myopathy:If on statins with elevated AST/CK, consider CoQ10 supplementation (100-200 mg daily) or switch to lower-potency statin

Address hemolysis:If indirect bilirubin and LDH also elevated, investigate for hemolytic anemia

3. Reduce Hepatotoxin Exposure

Limit alcohol:Even moderate drinking can elevate AST, especially in susceptible individuals

Review medications:Statins, NSAIDs, antibiotics, acetaminophen, and many supplements can elevate AST

Avoid acetaminophen overdose:Stay under 3000 mg/day;lower if alcohol consumption or other risk factors

Herbal supplements:Many supplements (green tea extract, anabolic compounds) can cause liver injury

Environmental toxins:Minimize exposure to pesticides, industrial solvents, and cleaning chemicals

4. Support Mitochondrial and Liver Health

Coenzyme Q10:100-300 mg daily supports mitochondrial function and may reduce statin-related AST elevation

N-acetylcysteine (NAC):600-1200 mg daily boosts glutathione, protects against oxidative liver damage

Vitamin E:400-800 IU daily (mixed tocopherols) reduces liver inflammation in NASH

Milk thistle:140-280 mg 2-3x daily supports liver regeneration and may reduce AST

Omega-3 fatty acids:2-4g EPA+DHA daily reduces inflammation and liver fat

5. Lifestyle Modifications

Regular exercise:150+ minutes/week moderate aerobic activity improves liver and cardiovascular health

Strength training:Builds healthy muscle mass and improves insulin sensitivity, but avoid overtraining

Adequate hydration:Especially important if muscle damage suspected;aim for 2-3 liters daily

Quality sleep:7-9 hours nightly;poor sleep worsens liver disease and metabolic dysfunction

Stress management:Chronic stress elevates cortisol and can worsen metabolic liver disease

Symptoms of Abnormal AST (Aspartate Aminotransferase)

Low AST (Aspartate Aminotransferase)

Low AST is uncommon and rarely clinically significant. Possible associations:
Vitamin B6 deficiency (AST requires pyridoxal phosphate as cofactor)
Severe kidney disease with uremia
Rare genetic enzyme deficiencies
Malnutrition or severe protein deficiency

High AST (Aspartate Aminotransferase)

Symptoms depend on underlying cause:
Liver-related:Fatigue, right upper quadrant pain, nausea, jaundice (if bilirubin elevated), dark urine
Heart-related:Chest pain, shortness of breath, palpitations, arm/jaw pain (if cardiac source)
Muscle-related:Muscle pain, weakness, dark urine (myoglobin), swelling (if rhabdomyolysis)
Often asymptomatic:Mild elevations (30-60 U/L) frequently cause no symptoms

Causes of Abnormal AST (Aspartate Aminotransferase)

Low Levels

Vitamin B6 (pyridoxine) deficiency
Chronic kidney disease, especially with dialysis
Severe malnutrition or low protein intake
Rare genetic variants (extremely uncommon)

High Levels

Liver causes:Fatty liver disease (NAFLD/NASH), alcoholic hepatitis (AST/ALT ratio >2), viral hepatitis (A, B, C), drug-induced liver injury, autoimmune hepatitis, cirrhosis (AST often higher than ALT), hemochromatosis, Wilson's disease
Cardiac causes:Myocardial infarction (heart attack), myocarditis, congestive heart failure, cardiac surgery
Muscle causes:Rhabdomyolysis (severe muscle breakdown), intense exercise, trauma, statin-induced myopathy, polymyositis/dermatomyositis
Hemolysis:Red blood cell breakdown from various causes (hemolytic anemia, transfusion reactions)
Other:Pancreatitis, kidney infarction, burns, heatstroke, celiac disease, hypothyroidism

When to Retest

After lifestyle changes:Retest in 8-12 weeks following diet, exercise, and alcohol cessation
After medication changes:If starting hepatotoxic medication or discontinuing suspected culprit, retest in 4-8 weeks
If moderately elevated (40-150 U/L):Retest every 3-6 months with comprehensive liver panel (ALT, ALP, GGT, bilirubin) and assess trend
If severely elevated (>150 U/L):Retest within 1-2 weeks with urgent workup including troponin (cardiac), CK (muscle), hepatitis panel, and imaging
Monitor AST/ALT ratio:If ratio increases over time (approaching or exceeding 2), suggests advancing fibrosis—consider liver elastography (FibroScan)
Annual screening:If metabolic risk factors present (obesity, diabetes, alcohol use), check annually

Scientific Evidence

AST/ALT Ratio for Diagnosis

The AST/ALT ratio is highly diagnostic for distinguishing causes of liver injury. Ratio <1 (AST lower than ALT) typically indicates NAFLD or acute viral hepatitis. Ratio >2 strongly suggests alcoholic liver disease with 70-80% sensitivity and specificity. Progressive increase in AST/ALT ratio over time indicates advancing fibrosis toward cirrhosis.

Source:Nyblom H, et al. The AST/ALT ratio as an indicator of cirrhosis in patients with PBC. Liver Int. 2006;26(7):840-845.

AST and Cardiovascular Mortality

Large population studies show elevated AST independently predicts cardiovascular mortality and all-cause death. Even mild elevations in the "high-normal"range (30-40 U/L) are associated with increased cardiovascular events. Each standard deviation increase in AST raises mortality risk by approximately 20%.

Source:Ndrepepa G, et al. Aspartate aminotransferase and mortality in patients with ischemic heart disease. Clin Chim Acta. 2017;466:135-140.

Mitochondrial AST in Severe Liver Injury

In acute liver injury, mitochondrial AST (mAST) is released from damaged mitochondria. The mAST/total AST ratio correlates with severity of hepatocellular necrosis. Very high AST levels (>10,000 U/L) almost always involve significant mitochondrial damage and indicate severe acute hepatitis, toxicity, or ischemic injury requiring urgent intervention.

Source:Kaplan MM. Serum aminotransferases and other markers of hepatocellular necrosis and inflammation. In:Hepatology:A Textbook of Liver Disease. 1996.

Statin-Induced Liver Enzyme Elevation

Statins cause mild AST/ALT elevation in 0.5-3% of patients. Most elevations are transient and clinically insignificant. However, persistent elevation >3x upper limit warrants statin discontinuation or dose reduction. Coenzyme Q10 supplementation may help reduce statin-related enzyme elevations without compromising efficacy.

Source:Russo MW, et al. Liver transplantation for acute liver failure from drug induced liver injury in the United States. Liver Transpl. 2004;10(8):1018-1023.

Exercise-Induced AST Elevation

Intense or unaccustomed exercise can significantly elevate AST (and CK) due to muscle damage, with levels potentially reaching 200-500 U/L. This is typically benign and resolves within 3-7 days with rest. Athletes should avoid testing within 48-72 hours of intense training to prevent misdiagnosis. Persistent elevation requires investigation.

Source:Brancaccio P, et al. Biochemical markers of muscular damage. Clin Chem Lab Med. 2007;45(6):757-762.

Which Providers Test AST (Aspartate Aminotransferase)?

Full Provider Comparison

Provider	Includes	Annual Cost	Biomarkers
Superpower	✓	$199	100+ (150 with ratios)
WHOOP Advanced Labs	✓	$349	65
Labcorp OnDemand	✓	$398	30+
Life Extension	✓	$486	40+
Everlywell	✓	$468	83
Mito Health	✓	$349	100+
InsideTracker	✓	$680	54
Function Health	✓	$365	100+
Marek Health Base	✓	$250	65
Marek Health Comprehensive	✓	$495	70+
Marek Health Complete	✓	$895	100+
Marek Health Executive	✓	$1950	150+
Blueprint	—	$399	100+
Quest Health	—	$Varies	75+
Empirical Health	✓	$190	100+
Oura Health Panels	✓	$99	50
SiPhox Health	✓	$125	60
Hims Labs Base	✓	$199	50
Hims Labs Advanced	✓	$499	120+
Healthspan	✓	$4188	80+
Vitality Blueprint Standard	✓	$375	85
Vitality Blueprint Elite	✓	$700	129

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Frequently Asked Questions

What does AST (Aspartate Aminotransferase) test for?

AST (Aspartate Aminotransferase) is a liver function biomarker. Enzyme found in liver and other tissues The normal reference range is 10-40 U/L.

Which providers include AST (Aspartate Aminotransferase)?

21 of 22 providers include this test:Superpower, Blueprint, Mito Health, WHOOP and others.

How often should I test AST (Aspartate Aminotransferase)?

For most people, testing 2-4 times per year is recommended to establish baseline levels and track trends. Consult your healthcare provider for personalized recommendations.

What is the optimal range?

The standard reference range is 10-40 U/L. Many functional medicine practitioners recommend tighter optimal ranges for peak health. Your ideal range may vary based on age, sex, and health goals.

Why is AST (Aspartate Aminotransferase) important?

Elevated in liver disease but also heart and muscle damage. AST/ALT ratio helps differentiate causes of liver injury. Less specific than ALT for liver disease.

Medical Disclaimer

This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs.