High ALT: What It Means and What to Do Next
High ALT (alanine aminotransferase) means liver cells are releasing more of this enzyme into your blood than usual, a sign of liver irritation or injury. The reference range JustLabs lists is 7–56 U/L, but many labs use lower upper limits that differ for men and women, so go by the range printed on your report. Mild elevations are common and often come from fatty liver, alcohol, medications or a hard workout. Very high levels, or a high ALT with yellow skin or eyes, need prompt medical care.
What Causes High ALT?
Fatty Liver Disease (MASLD)
The most common cause of a mildly high ALT in the US. Fat builds up in the liver, usually alongside excess weight, insulin resistance, type 2 diabetes or high triglycerides. It was formerly called NAFLD.
Alcohol
Regular heavy drinking inflames the liver. In alcohol-related liver disease, AST is often higher than ALT.
Medications and Supplements
Statins often cause a small, usually harmless rise. Acetaminophen above recommended doses, or with heavy drinking, can seriously injure the liver. Some antibiotics, anti-seizure drugs, and herbal or bodybuilding supplements can also raise ALT.
Viral Hepatitis B or C
Chronic hepatitis B or C can keep ALT elevated for years with no symptoms while slowly damaging the liver. Both are found with a blood test.
Intense Exercise or Muscle Injury
ALT is also found in muscle. Heavy weight training, long endurance events or a muscle injury can raise ALT and AST for several days.
Celiac Disease
Untreated celiac disease can cause a mild, otherwise unexplained ALT elevation that usually settles on a gluten-free diet.
Iron Overload (Hemochromatosis)
An inherited tendency to absorb too much iron, which is stored in the liver. High ferritin and high transferrin saturation point toward it.
Thyroid Problems
Both an underactive and an overactive thyroid can raise liver enzymes, which often return to normal once the thyroid is treated.
Associated Symptoms
What to Do Next
1. Retest to confirm
A single abnormal result should be confirmed with a repeat test. Temporary factors like stress, illness, or medications can affect results.
2. Related tests to consider
3. When to see a doctor
If your ALT is significantly abnormal, if you have severe symptoms, or if repeated results confirm the abnormality, consult a healthcare professional for appropriate evaluation and treatment.
Related Conditions
Frequently Asked Questions
Related Articles
This page is for informational purposes only and does not constitute medical advice. Consult a healthcare provider for interpretation of your results.
Content reviewed for accuracy by the JustLabs editorial team.