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ALT (Alanine Aminotransferase)

Doctor's Assessment Included

Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.

Liver

ALT blood value: what a high or normal ALT level can mean

ALT is a liver enzyme that athletes should monitor regularly. Intense training, high-protein diets, and performance supplements can all influence liver enzyme levels, making ALT an important marker for athletic health management.

Reference Ranges

Male

u/l

Low 0 Normal 45 High

Female

u/l

Low 0 Normal 35 High

Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.

What It Measures

ALT is found mainly in the liver; it is a particular substance (an enzyme) found predominantly in liver cells. When liver cells are damaged, ALT is released into your blood and the value rises. A normal ALT value usually points to calm liver function.

This test measures the amount of ALT in your blood. ALT is more specific to the liver than some other enzymes, such as AST. That makes it a widely used marker to look at your liver.

Why It Matters

A high ALT value can have different causes, from viral hepatitis (such as hepatitis B) to fatty liver. Doctors often look at AST and ALT together, and sometimes at gamma-GT, to get a broader view. A slightly raised value usually means something different from a strongly raised value. An abnormal value on its own does not confirm a diagnosis. Your GP can help you decide whether further steps are needed.

If your ALT value is too high, this can have different causes and does not automatically mean something serious is going on. Your GP can help you decide whether further steps are needed.

When to Test

An ALT test is useful for symptoms that may point to the liver, such as persistent fatigue, nausea, abdominal pain in the upper right quadrant, or yellowing of the skin and eyes (jaundice). But it is also frequently requested without symptoms, as a preventive check.

During long-term use of medications that can burden the liver (statins, methotrexate, anti-epileptics), periodic ALT monitoring is standard practice. The same applies to known obesity or type 2 diabetes, due to the increased risk of fatty liver.

After a hepatitis infection or in chronic hepatitis B or C, regular ALT monitoring is essential to track disease activity. Fasting is not required for the test, although some laboratories recommend it for combined liver panels.

Symptoms

Low Levels

A low ALT is normal and indicates no measurable liver damage. There are no symptoms associated with a low ALT value. It is a favourable result.

High Levels

Mildly elevated ALT (1–3 times the upper limit) often causes no direct symptoms and is frequently discovered incidentally. The most common causes are fatty liver, obesity, and medication use.

With moderately to significantly elevated ALT (3–10 times the upper limit), symptoms may include fatigue, reduced appetite, nausea, and a pressing sensation in the right side of the abdomen. This is consistent with active liver inflammation, for example from hepatitis or a toxic reaction.

With very significantly elevated ALT (more than 10 times the upper limit, i.e., above 350–450 U/L), acute liver damage is present. This can occur in acute viral hepatitis, paracetamol poisoning, or ischaemic liver injury. Symptoms include jaundice, dark urine, pale stools, and severe fatigue. This requires immediate medical attention.

Recommendations

Male

If Low

Normal ALT indicates healthy liver function. Maintain a balanced diet and moderate alcohol consumption.

If High

Elevated ALT may indicate liver cell damage. Consider reducing alcohol intake, reviewing medications, and consulting your healthcare provider for liver evaluation.

Female

If Low

Normal ALT indicates healthy liver function. Maintain a balanced diet and moderate alcohol consumption.

If High

Elevated ALT may indicate liver cell damage. Consider reducing alcohol intake, reviewing medications, and consulting your healthcare provider for liver evaluation.

Lifestyle Tips

Elevated ALT is reversible through lifestyle adjustments in many cases. For fatty liver — the most common cause — weight loss is the most effective measure. As little as 5–10% weight loss can significantly improve liver values.

Limit alcohol consumption, or stop entirely if your liver values are elevated. Even with non-alcoholic fatty liver, alcohol can worsen damage. Avoid unnecessary high-dose paracetamol use and be cautious with dietary supplements — some herbal preparations are hepatotoxic.

A diet limited in sugar, low in saturated fat, and rich in vegetables, fruit, and whole grain products supports liver recovery. Regular exercise — even 150 minutes per week — improves insulin sensitivity and reduces liver fat, even without weight loss.

Frequently Asked Questions

What causes elevated ALT levels?

Common causes include fatty liver disease, hepatitis, excessive alcohol consumption, certain medications, and obesity. Intense exercise can also temporarily raise ALT levels.

Can ALT levels return to normal?

Yes, in many cases ALT levels can normalize with lifestyle changes such as reducing alcohol intake, losing weight, or adjusting medications. Consult your healthcare provider for personalized guidance.

How often should ALT be tested?

Some people choose to test periodically; your GP can help you decide what suits you. If you have known liver conditions or take medications that can put a strain on the liver, more frequent monitoring may be useful.

Test Products

This marker is included in the following test panels.

Hormones & TRT

TRT Monitoring

Monitoring panel for testosterone replacement therapy: hormones, liver, lipids, PSA, and blood count.

PSA (Prostate-Specific Antigen) Prolactin ALT (Alanine Aminotransferase) Triglycerides ALP (Alkaline Phosphatase) AST (Aspartate Aminotransferase) GGT (Gamma-Glutamyl Transferase) LDL Cholesterol SHBG (Sex Hormone Binding Globulin) Estradiol (E2) Free Testosterone Total Testosterone HDL Cholesterol Albumin Complete Blood Count (CBC)

€250,-