Key takeaways

  • Metabolic dysfunction-associated steatotic liver disease (MASLD) occurs when excess fat builds up in the liver. It can develop when the body produces too much fat or cannot metabolize it properly, often alongside conditions like obesity, type 2 diabetes, high cholesterol, and high blood pressure.
  • MASLD often does not cause noticeable symptoms until it progresses, but some people develop metabolic dysfunction-associated steatohepatitis (MASH), an inflammatory stage that can lead to cirrhosis and liver failure. Cirrhosis is a type of severe scarring that causes liver dysfunction.
  • There is no medical treatment for MASLD, but weight loss, eating whole grains and fresh produce, choosing healthy oils, limiting red meat and added salt and sugar, exercising at least 30 minutes most days, and avoiding alcohol may reverse some damage.

Doctors may diagnose MASLD when fat accounts for 5% or more of the liver’s weight.

MASLD does not always progress. However, it can also worsen in stages, with some people going on to develop severe inflammation and scarring that causes liver dysfunction and liver failure.

MASLD was previously known as nonalcoholic fatty liver disease (NAFLD). MASH was previously known as nonalcoholic steatohepatitis (NASH).

These new names are more accurate, help reduce the stigma associated with the older names, and familiarize people with the link to metabolic dysfunction and metabolic syndrome, as well as their roles as multiorgan conditions.

MASLD is a type of chronic liver condition caused by excess fat in the liver.

While MASLD does not always progress, it can worsen in stages. MASLD can progress to metabolic dysfunction-associated steatohepatitis (MASH), a severe form of inflammation and scarring called fibrosis. MASH may eventually result in cirrhosis, a late-stage of liver scarring that can lead to complications like liver failure and liver cancer.

MASLD often does not cause any noticeable symptoms, even if it progresses and starts to cause liver damage.

Still, about 24% of adults in the United States may have MASLD but no inflammation or damage. MASH affects around 1.5% to 6.5% of this adult population.

Fat can build up in the liver for a range of reasons, including during pregnancy. Cirrhosis can stem from high alcohol consumption, but MASLD and MASH do not result from this.

Below, we explore MASLD in detail, including its treatments.

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The liver removes toxins from the body. If it does not work correctly, various issues can arise.

If the body produces too much fat or does not metabolize fat correctly, it can accumulate in the liver. This is often referred to as having a “fatty liver.” If fat continues to accumulate, inflammation can result. Eventually, it can lead to scarring and liver failure.

MASLD

The first stage of MASLD is steatosis, or fatty liver. This refers to when more than 5% to 10% of the liver’s weight comprises fat. This is not healthy, but it often does not cause noticeable symptoms or have a severe impact on liver function at this stage.

If a person does have early symptoms of MASLD, they are typically subtle or vague, such as:

  • fatigue
  • sharp, dull, or aching abdominal pain
  • increased thirst
  • bloating
  • sleep disturbances, such as sleep apnea

Many people with fatty liver do not know that they have it. They may find out during routine tests for another condition, or a doctor may recommend testing because of risk factors.

For most people, MASLD does not progress further.

About 24% of adults and 10% of children in the U.S. have MASLD, according to the National Institute of Diabetes and Digestive and Kidney Diseases.

MASH with mild fibrosis

If fat continues to accumulate, MASLD can progress to MASH. MASH affects around 1.5% to 6.5% of adults in the U.S.

The first stage of MASH describes when MASLD has begun to cause liver inflammation, but there is little to no fibrosis (scarring). At this stage, treatment and lifestyle approaches can still reverse damage and the underlying MASLD.

Some people with early MASH may still not experience any noticeable symptoms.

MASH with moderate fibrosis

MASH with moderate fibrosis is when inflammation and damage begin to cause scarring. At this stage, most of the damage may be repairable with effective treatment, and the liver may still be working as needed.

MASH with advanced fibrosis

MASH with advanced fibrosis describes when MASH is causing significant scarring in the liver. At this stage, it is critical to get treatment to stop further scarring and liver damage.

Some damage at this stage may be repairable, but some may not.

Cirrhosis and liver failure

Cirrhosis is a severe, late-stage form of scarring that can cause permanent damage, changes in the liver’s shape, and liver dysfunction. Cirrhosis can also lead to liver failure and liver cancer.

Some damage may be irreversible, and treatment at this stage largely focuses on preventing liver health from getting worse by stopping or slowing further damage.

In some cases, MASH may not cause symptoms until it has reached cirrhosis.

Symptoms of cirrhosis include:

  • tiredness and weakness
  • nausea, vomiting, and diarrhea
  • red or discolored patches on the palms of the hands
  • spider-like veins under the skin above the waist
  • pale or dark, tarry stools
  • dark urine
  • itching
  • jaundice
  • abdominal swelling and pain, due to a buildup of fluid
  • swelling of the ankles, feet, and legs
  • easy bleeding and bruising
  • changes to menstruation
  • enlarged breasts in people assigned male at birth
  • swelling of the scrotum
  • loss of sexual desire
  • confusion, difficulty focusing, memory loss, and hallucinations
  • behavioral or personality changes

Around 10% to 25% of people with MASH develop cirrhosis and liver failure, though this can take time, such as decades.

In severe cases, a person may need a liver transplant.

Treatment approaches depend on the stage of MASLD and MASH.

There are limited medical treatments for MASLD, but various strategies can reduce the risk of further liver problems and may reverse some damage that already exists.

  • weight loss, which can include weight loss medications, if necessary
  • avoiding alcohol
  • exercising for at least 30 minutes a day on most days of the week
  • following a balanced, Mediterranean-style diet, such as by:
    • eating plenty of whole grains, fresh fruits, and vegetables
    • limiting the intake of highly processed foods, red meat, and saturated fats
    • swapping out saturated fats for unsaturated fats, such as olive, soybean, safflower, or other vegetable oils
    • avoiding foods containing added salt or sugar

Significant fat loss — such as a decrease of 3% to 5% in body weight or more — is currently one of the most effective treatments for MASLD. A 2025 study reported that body weight loss of 8% to 12% effectively improved insulin sensitivity and reduced liver fat levels. These impacts were linked to a 38% decrease in VLDL-triacylglycerol levels, a type of fat linked to MASLD.

Treatment for MASLD that has advanced to MASH or cirrhosis may include:

Researchers are investigating which new medications and supplements may help improve MASH, including:

  • vitamin E supplements for people with MASH but without diabetes or cirrhosis
  • pioglitazone (Actos) for people with MASH but without cirrhosis

Other ways people can help protect their livers while managing any stage of MASLD include:

  • following doctors’ instructions for taking any medications
  • always seeking medical advice before using vitamins, supplements, or herbal remedies — even those available over the counter
  • avoiding smoking
  • getting regular checkups to monitor liver health
  • following treatment recommendations for other underlying conditions, such as insulin resistance
  • having vaccinations for hepatitis A and B

A tailored diet and exercise plan may also reduce the risk of various conditions, including obesity, diabetes, and cardiovascular disease, that often occur alongside MASLD.

Doctors do not know exactly how or why MASLD develops. It appears to occur when the body produces excess fat or cannot process it properly.

There are some risk factors, which include:

  • obesity
  • type 2 diabetes, high cholesterol levels, high blood pressure, and other features of metabolic syndrome
  • any health condition that affects the body’s ability to use or store fat
  • rapid weight loss or malnutrition
  • some medications, including corticosteroids, estrogens, some HIV drugs, and some cancer drugs
  • genetic factors, including rare genetic diseases
  • smoking
  • exposure to some toxins

Since early stage MASLD does not usually produce symptoms, the diagnosis often follows a routine check or a test due to risk factors.

If a doctor suspects MASLD, they will:

  • check the abdominal area for swelling
  • ask about the person’s diet, lifestyle, and alcohol consumption
  • consider the person’s use of medications and supplements
  • recommend imaging and other tests to rule out other possible health conditions
  • do a biopsy to confirm MASLD and assess the extent of any damage

A 2024 study reported that having MASLD was linked to a 16% increase in mortality rates compared to people without any kind of steatotic liver disease.

However, the outlook of MASLD can vary greatly depending on whether a person goes on to develop MASH and cirrhosis.

Cirrhosis can be fatal, and some people with cirrhosis may need a liver transplant. In people with MASLD, cirrhosis is the third most common cause of death in the U.S. after cardiovascular disease and cancer. People with MASLD and MASH may also have a higher risk of developing liver cancer.

Getting an early diagnosis for MASLD and following treatment plans as prescribed can reduce the risk of serious complications, like MASH and cirrhosis, and improve the outlook. In some cases, MASLD without MASH or cirrhosis can be reversed with treatment.

MASLD occurs when excess fat builds up in the liver. For many people, MASLD does not progress. In other cases, MASLD can progress to MASH, whereby fat buildups start to cause more serious liver inflammation, damage, and scarring causing liver dysfunction.

There are often no symptoms until MASH or cirrhosis has developed. To help increase the chance of early detection and better treatment outcomes, a person with risk factors for MASLD, such as diabetes or overweight, can talk with a doctor about screening and diagnosis.

Weight management, dietary changes, and regular exercise can help prevent and manage MASLD and reduce the risk of it progressing.