What are liver enzymes?

Liver enzymes are proteins that drive the chemical reactions inside liver cells. When the liver is healthy, they stay put. When the liver is inflamed or damaged, they leak into the bloodstream. That leak is what shows up as an "elevated" number on your blood work.

Elevated enzymes don't name a specific disease. They're a signal that the liver is under stress, and the pattern of which enzymes are up gives a hint about why.

The enzymes worth knowing

• Alanine aminotransferase (ALT): mostly found in the liver. It helps turn proteins into energy for liver cells. A rise in ALT is usually the earliest indicator of liver injury (hepatitis, fatty liver disease).
• Aspartate aminotransferase (AST): in the liver, but also in muscle, heart, and kidney. Because it isn't liver-specific, AST is read alongside ALT.
• Alkaline phosphatase (ALP): in the liver, bones, kidneys, and bile ducts. A high ALP often points to a bile-flow problem, but bone disease can drive it up too.
• Gamma-glutamyl transferase (GGT): involved in drug and toxin metabolism. Often elevated with heavy alcohol use or bile duct issues.

What causes elevated liver enzymes?

Non-alcoholic fatty liver disease (NAFLD)

NAFLD is one of the most common causes, especially in people with obesity, insulin resistance, or metabolic syndrome. Fat accumulates in liver cells, drives inflammation, and damages the tissue over time. Most people feel nothing in the early stages. Fatigue or a vague upper-right abdominal discomfort can appear later. Risk factors: obesity, type 2 diabetes, high cholesterol, high triglycerides.

Medications and supplements

A lot of common drugs can bump up ALT and AST. Statins, high-dose acetaminophen, and certain antibiotics are the usual suspects. On the supplement side, kava, valerian, and high-dose vitamin A can be hepatotoxic. Tell your provider what you actually take, including the bottle of "liver detox" from the natural-foods store.

Alcohol

Chronic heavy drinking inflames and scars the liver. Over years, this can become alcoholic liver disease or cirrhosis. GGT is often the first enzyme to rise. Jaundice, fatigue, and abdominal pain come later.

Viral hepatitis

Hepatitis B and C inflame the liver and push ALT and AST up, sometimes dramatically. Both spread through blood and body fluids: unprotected sex, shared needles, and (for hep B) mother to child during birth. Untreated, both can cause chronic liver damage.

Other liver conditions

• Autoimmune hepatitis: the immune system attacks liver cells. Long-term damage if untreated; usually managed with immunosuppressants.
• Bile duct obstruction: gallstones or tumors blocking the ducts cause bile backup. ALP and GGT rise together.
• Liver cancer: elevated enzymes with weight loss, persistent pain, or a palpable mass warrant urgent imaging.

How to read the numbers

How high is too high?

Liver enzymes are measured in units per litre (U/L). Reference ranges:

• Normal:
  • AST: 10 to 40 IU/L
  • ALT: 7 to 55 IU/L
• Mild elevation (1 to 3x ULN): often temporary stress: a medication, a recent infection, a workout. Doesn't always need immediate action, but worth re-checking.
• Moderate elevation (3 to 5x ULN): bigger picture stuff. NAFLD, alcohol use, chronic viral hepatitis. Needs investigation and usually lifestyle or treatment changes.
• Severe elevation (>5x ULN): acute hepatitis, cirrhosis, drug-induced injury, or cancer until proven otherwise. Requires medical attention.

ALT vs AST ratios

• ALT > AST: typically non-alcoholic causes: NAFLD or viral hepatitis. ALT is more specific to liver cells, so a higher ALT/AST points to hepatocellular injury.
• AST > ALT: can suggest alcoholic liver disease, since AST is more abundant in liver, heart, and muscle. Also flags damage outside the liver.
• AST/ALT ratio > 2: classically alcohol-related liver damage.

What ALP and GGT add

• ALP and GGT both up: usually a bile-duct problem: gallstones, cholestasis, ductal inflammation, or a tumor obstructing flow.
• ALP up but GGT normal: think bone, not liver.

One-off vs persistent

A single mildly elevated result after a heavy workout or a fatty meal usually clears on its own. Enzymes that stay up over weeks to months are different. That pattern needs a workup.

What happens next

Follow-up blood tests

• Viral hepatitis panel: screens for hep A, B, and C.
• Full liver function tests: bilirubin, albumin, prothrombin time. These measure how well the liver is actually working, not just how much it's leaking.
• Autoimmune markers: ANA, anti-smooth muscle antibodies if autoimmune hepatitis is on the differential.
• Iron and copper studies: for hemochromatosis or Wilson's disease.

Imaging

• Ultrasound: the usual first imaging test. Catches fatty liver, tumors, cysts, and obstructions. Non-invasive, fast, available.
• CT or MRI: when more detail is needed. Better characterization of masses, cirrhosis, vascular flow.
• FibroScan: measures liver stiffness as a proxy for fibrosis. A non-invasive alternative to biopsy in chronic liver disease.

Liver biopsy

Reserved for cases where bloods and imaging don't add up, or where staging matters. A small tissue sample is taken with a needle under ultrasound or CT guidance. Useful for diagnosing NASH, autoimmune hepatitis, and cancer, and for grading inflammation and fibrosis.

Watch and wait

For mild elevations with no obvious cause, repeat bloods every few weeks to months are often all that's needed. If they normalize, the liver has shaken off whatever was bothering it.

Treatment

Lifestyle

• Diet: cut processed foods, saturated fats, and added sugars. Lean toward whole foods. For fatty liver disease, weight loss alone often drops ALT and AST.
• Exercise: aim for at least 150 minutes of moderate activity per week. Reduces liver fat and improves insulin sensitivity.
• Alcohol: cut back or stop. Even moderate intake can keep an inflamed liver inflamed.

Medications

• Adjusting offenders: if a statin or antibiotic is the trigger, the dose or drug may be changed.
• Targeted treatment: antivirals for hep B or C, corticosteroids or other immunosuppressants for autoimmune hepatitis.

Treating the cause

• NAFLD: weight loss, diet, exercise. Blood sugar and cholesterol control where relevant.
• Viral hepatitis: modern antivirals can fully cure hep C and suppress hep B.
• Bile duct obstruction: may need ERCP or surgery to clear the blockage.

Monitoring

Repeat blood tests track whether treatment is working. If enzymes stay elevated despite changes, the plan needs revising.

FAQ & recap

What would cause your liver enzymes to be high?

Fatty liver disease (alcoholic and non-alcoholic), hepatitis (viral or autoimmune), medications like statins and acetaminophen, heavy alcohol use, and metabolic disorders. Infections, obesity, and even strenuous exercise can cause temporary bumps.

How do you fix elevated liver enzymes?

Treat the cause. That might mean weight loss, less alcohol, better blood sugar control, or stopping a medication. Infections and inflammation get treated directly. Regular follow-up bloods confirm the levels are dropping.

What does it mean if both AST and ALT are high?

Usually liver cell injury or inflammation: hepatitis, alcoholic liver disease, or NAFLD. The ratio of AST to ALT helps narrow the cause. AST higher than ALT often suggests alcohol.

Can dehydration cause elevated liver enzymes?

On its own, no. Severe dehydration can stress the body generally and worsen an underlying problem, but it isn't a direct driver of high ALT or AST.

What is an alarming ALT level?

Anything over about 200 IU/L gets attention. Over 1,000 IU/L typically signals acute hepatitis or drug-induced liver injury and needs prompt medical evaluation.

What cancers cause elevated liver enzymes?

Hepatocellular carcinoma (primary liver cancer) and any cancer that metastasizes to the liver. Pancreatic cancer and bile duct cancer can also push enzymes up by obstructing flow.

What should I avoid if I have high liver enzymes?

Alcohol first. Acetaminophen at high doses and anything else hepatotoxic. Cut back on processed foods, sugar, and unhealthy fats. Run major diet or medication changes by your provider.

Can stress cause elevated liver enzymes?

Indirectly. Chronic stress drives the behaviours (poor eating, drinking, missed sleep) that hurt the liver. Stress on its own isn't a direct cause.

Why is my ALT high but everything else normal?

Often an early or mild liver issue: NAFLD, mild viral hepatitis, or a medication effect. Repeat the test in a few weeks and review your meds and supplements with your provider.

Check your liver enzymes with TeleTest

If you're worried about your liver, whether because of medications, alcohol, supplements, or symptoms like fatigue and right-sided discomfort, a liver function panel can give you a clear answer. TeleTest offers online blood testing in Ontario and BC. Complete a short intake, get your requisition, visit any partner lab. Results typically land in 1 to 3 business days.

For people using performance-enhancing substances (oral steroids, SARMs, prohormones), regular liver enzyme monitoring matters. Hepatotoxic compounds can drive significant ALT/AST elevation before any symptoms appear. Test before starting a cycle, mid-cycle, and 4 to 6 weeks after completion.

Disclaimer: This blog post is for educational purposes only and is not medical advice. Talk to your healthcare provider about your specific situation.

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