Nonalcoholic steatohepatitis (NASH) is a type of nonalcoholic fatty liver disease (NAFLD). It involves a buildup of fat in your liver, inflammation, and damage.

Nonalcoholic steatohepatitis (NASH) is now known as metabolic dysfunction-associated steatohepatitis (MASH). This new name is more accurate and helps reduce the stigma associated with its older name.

According to the American Association for the Study of Liver Diseases (AASLD), the name change took effect in June 2023 and was agreed upon by a group of multinational liver societies and organizations.

MASH is a more severe form of NAFLD than simple nonalcoholic fatty liver (NAFL).

NAFL involves a buildup of fat in your liver, with little to no inflammation or liver damage. NAFL sometimes progresses into MASH over time.

Potential complications of MASH include:

  • cardiovascular disease
  • fibrosis, which is scarring of your liver
  • cirrhosis, which is severe fibrosis
  • liver cancer
  • liver failure

Weight loss and healthy lifestyle habits may help reduce the buildup of fat, inflammation, and liver damage, lowering your risk of complications from MASH.

Sometimes, your doctor may also recommend medication to treat MASH.

Learn more about MASH, including the potential symptoms, treatment options, and outlook.

MASH usually causes no noticeable symptoms, although it may cause pain or discomfort in your upper right abdomen.

Advanced fibrosis or cirrhosis from MASH may cause more noticeable symptoms, such as:

  • tiredness
  • skin itching
  • mental changes
  • reduced appetite
  • nausea and vomiting
  • muscle loss and weakness
  • easy bruising or bleeding
  • jaundice, which is the yellowing of your skin or eye whites
  • edema, which is swelling in your feet, ankles, and lower legs
  • ascites, which is swelling in your abdomen caused by a buildup of fluid

Contact your doctor if you notice any of these symptoms.

A combination of genetic and environmental factors may cause MASH. Your risk of MASH is increased if you have a family history of MASH or NAFL.

Your risk of MASH is also higher if you have certain health conditions, such as:

  • overweight or obesity
  • insulin resistance
  • type 2 diabetes
  • high blood sugar
  • dyslipidemia, which includes:
    • high levels of triglycerides in your blood
    • high total cholesterol in your blood
    • high low-density lipoprotein (LDL) cholesterol in your blood
    • low high-density lipoprotein (HDL) cholesterol in your blood
  • high blood pressure

Scientists are also researching the potential role of dietary patterns or gut bacteria in MASH.

It’s possible that a diet high in sweetened foods and beverages may raise your risk of MASH, although more research is needed to confirm this potential risk factor.

Your doctor might diagnose MASH after a routine blood test shows increased liver enzymes, including alanine aminotransferase (ALT) and aspartate aminotransferase (AST).

Your doctor may order liver enzyme tests as part of a routine checkup or if you have certain symptoms.

To learn whether MASH or another condition is causing increased liver enzymes, your doctor will:

  • ask about your medical history
  • conduct a physical exam
  • order follow-up tests, including imaging

Other potential causes of increased liver enzymes include:

  • alcohol-associated liver disease
  • malnutrition or rapid weight loss
  • exposure to certain toxins
  • autoimmune hepatitis or viral hepatitis, such as hepatitis B or C
  • lipodystrophies, which are health conditions that cause improper fat use or storage
  • rare genetic conditions, such as hypobetalipoproteinemia or Wilson disease
  • side effects from certain medications or herbal supplements

There’s no single test that can diagnose MASH, which is why your doctor needs to use the information and tests below to rule out other potential causes of increased liver enzymes.

Medical history

Your doctor will ask about your lifestyle habits and medical history, including:

  • your diet, alcohol intake, and physical activity
  • any medications or supplements that you take
  • other health conditions that you have
  • symptoms or changes in your health

Physical exam

Your doctor will conduct a physical exam to check for:

  • enlarged liver
  • signs of cirrhosis
  • signs of insulin resistance

They may also measure your weight and height during your physical exam.

Medical tests

Your doctor will order blood tests to measure your liver enzymes, including ALT and AST.

They may also order:

  • additional blood tests
  • imaging tests to examine your liver
  • a liver biopsy, which is a small sample of the liver that’s examined under a microscope

These tests can help them learn whether increased liver enzymes are caused by MASH, NAFL, or another health condition. Follow-up tests can also help them learn how much liver inflammation and damage you may have.

Your doctor may recommend one or more of the following treatments for MASH:

  • weight loss
  • changes to your diet, alcohol intake, physical activity, or other lifestyle habits
  • resmetirom (Rezdiffra), which is a medication to help reduce fatty liver

Your doctor will order regular follow-up tests to monitor your condition and check for signs of complications, such as cirrhosis. They may recommend additional treatments if you develop complications.

Following your doctor’s recommended treatment is important for preventing complications from MASH.

Consider asking your doctor for a referral to a registered dietitian or other specialist who can help you make healthy lifestyle changes to support weight loss and liver health.

It’s also important to talk with your doctor about any medications or supplements you take. Certain medications or supplements may damage your liver. Talk with your doctor before you start taking any new medications or supplements.

MASH sometimes causes noticeable symptoms, such as mild discomfort or pain in the upper right part of your abdomen. Let your doctor know if you develop this symptom or other changes to your health.

Contact your doctor right away if you think you may have symptoms of cirrhosis or other complications from MASH.

MASH, cirrhosis, and other forms of liver disease are often diagnosed following routine blood tests.

Ask your doctor how often you should get routine blood tests.

Following your doctor’s recommended treatment for MASH is important for reducing the buildup of fat, inflammation, and damage in your liver. This may help reverse MASH or reduce your risk of complications.

Your outlook is worse if you develop cirrhosis or other complications from MASH. According to a 2021 report, there has been a 105.56% increase in liver cirrhosis caused by MASH from 1990 to 2017. It’s a serious condition that can cause life threatening liver failure.

People with MASH also have an increased risk of cardiovascular disease and type 2 diabetes.

Talk with your doctor to learn how to improve your outlook with MASH.

MASH involves a buildup of fat in your liver, as well as liver inflammation and damage. It can cause potentially life threatening complications, such as cirrhosis and liver failure.

Your doctor may recommend weight loss and healthy lifestyle changes to help treat MASH and reduce your risk of complications. Sometimes they may prescribe medication or other treatments.

Talk with your doctor to learn more about your treatment options and outlook with MASH.