What does it mean if only alanine aminotransferase (ALT) is elevated?

Generally, elevated alanine aminotransferase (ALT) levels alone may be caused by factors such as intense physical exercise, staying up late and fatigue, non-alcoholic fatty liver disease, drug-induced liver injury, or viral hepatitis. It is recommended to seek medical attention promptly, identify the underlying cause, and receive appropriate treatment under a doctor's guidance. Specific analyses are as follows:

1. Intense physical exercise: High-intensity exercise increases the permeability of liver cells, leading to the release of ALT into the bloodstream and resulting in elevated levels. After exercising, ensure adequate rest and avoid strenuous activity in the short term. Re-examination after 1–2 weeks usually shows normalization.

2. Staying up late and fatigue: Long-term sleep deprivation or excessive fatigue deprives the liver of sufficient rest, impairing its metabolic function and causing elevated indicators. Maintaining regular作息 (sleep patterns), ensuring 7–8 hours of sleep per day, avoiding late nights, and following a light diet can improve the condition.

3. Non-alcoholic fatty liver disease: Accumulation of fat within liver cells damages them, leading to enzyme leakage. Control dietary fat intake, increase aerobic exercise, and take medications such as silibinin capsules, polyene phosphatidylcholine capsules, or diammonium glycyrrhizinate enteric-coated capsules as directed by a physician.

4. Drug-induced liver injury: Long-term use of hepatotoxic drugs can damage liver cells. Immediately discontinue any suspected medication and follow medical advice to use liver-protective agents such as reduced glutathione tablets, tiopronin enteric-coated tablets, or compound glycyrrhizin tablets to support liver recovery.

5. Viral hepatitis: Hepatitis B or C viruses invade and damage liver cells. For hepatitis B, medications such as entecavir tablets, tenofovir disoproxil fumarate tablets, or lamivudine tablets may be prescribed. Hepatitis C is treated with direct-acting antiviral agents. In severe cases, liver transplantation may be necessary to restore liver function.

In daily life, avoid alcohol consumption, reduce intake of high-fat and high-sugar foods, and undergo regular liver function tests. Maintaining healthy lifestyle habits helps support liver health and stabilize ALT levels.