Metabolic dysfunction-associated steatotic liver disease (MASLD) used to be called nonalcoholic fatty liver disease. MASLD is when fat builds up in your liver because of extra body weight, high blood sugar, high cholesterol, or high blood pressure. If the liver has both fat buildup and inflammation, it's called metabolic dysfunction-associated steatohepatitis (MASH).

Doctors don't know the exact cause of metabolic dysfunction-associated steatotic liver disease. Certain health conditions are closely linked to MASLD. These include obesity, insulin resistance, metabolic syndrome, type 2 diabetes, high cholesterol, and high triglycerides. These conditions may lead to extra fat in the liver or MASLD.

Children and young adults can get this disease. But it is most common in middle age. Risk factors include:

• Having excess weight, especially having too much belly fat.
• Having high blood fat levels (either triglycerides or LDL cholesterol).
• Having type 2 diabetes or prediabetes.
• Having high blood pressure.

When these risk factors happen together, they cause a health problem called metabolic syndrome. People with metabolic syndrome often have fatty liver. They also are more likely to have heart disease. Other conditions that may raise your risk include polyendocrine metabolic ovarian syndrome (PMOS), sleep apnea, and hypothyroidism.

MASLD is sometimes called a silent liver disease. This is because it can happen without causing any symptoms. Most people with MASLD live with fat in their liver without getting liver damage. A few people who have fat in their liver develop metabolic dysfunction-associated steatohepatitis (MASH).

If you have MASH, you may have symptoms. But it could take years for them to show up. Sometimes liver damage from MASH causes long-term scarring and hardening of your liver. This is called cirrhosis. It also increases risk for liver cancer. Symptoms from MASH may include:

• Severe tiredness (fatigue).
• Pain in the right upper belly (abdomen).
• Weakness.
• Weight loss.
• Yellowing of the skin or eyes (jaundice).
• Spiderlike blood vessels on the skin.
• Long-lasting itching.

MASH that turns into cirrhosis could cause these symptoms:

• Extra fluid buildup (fluid retention)
• Internal bleeding
• Muscle wasting
• Confusion

These symptoms may look like other health problems. Always see your doctor for a diagnosis.

MASLD can happen without causing any symptoms. It's often diagnosed when you have routine blood tests to check your liver. Your doctor may think you have it if your test results are abnormal. This is especially true if you have obesity or diabetes.

Your doctor may use these tests to help make a diagnosis:

• Imaging tests. Ultrasound, CT scan, or MRI may show fat deposits in your liver.
• Blood tests. Blood tests may be used to check how well your liver is working. They can also check for other causes of liver disease.
• Liver biopsy. The doctor puts a long needle through your skin into your liver. The needle removes a small piece of liver tissue. The tissue can be looked at under a microscope.

Based on the test results, your doctor will make the following diagnosis:

• You have MASLD if you have fat but no inflammation or tissue damage.
• You have MASH if you have fat, inflammation, and liver damage.
• You may be developing cirrhosis if you have a type of scar tissue in your liver called fibrosis.

If you have MASLD without any other health problems, you don't need any special treatment. But making some lifestyle changes can control or reverse the fat buildup in your liver. These may include:

• Losing weight.
• Lowering your cholesterol and triglycerides.
• Controlling your diabetes, if needed.
• Not drinking alcohol.

If you have MASH, sometimes the liver damage stops or even reverses itself. But for other people, the disease keeps getting worse. If you have MASH, it's important to control any conditions that may help cause the disease. Treatments and lifestyle changes may include:

• Losing weight.
• Exercising more.
• Taking medicine to lower cholesterol or triglycerides.
• Taking medicine to lower blood pressure.
• Taking medicine to control diabetes.
• Limiting over-the-counter medicines.
• Not drinking alcohol. No amount of alcohol is known to be fully safe once you have MASH.
• Eating a diet low in fat and simple carbohydrates.
• Seeing a liver specialist.

Your doctor may advise certain medicines if you have MASH. These include vitamin E in people without diabetes or heart disease. And they include pioglitazone, a diabetes medicine for people with or without diabetes. But these have side effects, so talk about them with your doctor. Other medicines, including certain herbal supplements, are being looked into. Treating the underlying conditions is very important. Rezdiffa (resmetirom) was FDA approved in March 2024 for the treatment of MASH, when patients have stage 2 or stage 3 fibrosis. It has been shown to be a safe and effective treatment, as it both slows the progression of fibrosis and also can lead to an improvement in the amount of fibrosis.

The main complication is that MASH can become cirrhosis. Cirrhosis means lasting (permanent) scarring and hardening of the liver. People with cirrhosis may develop liver failure and need a liver transplant. MASH may also progress to liver cancer. Talk with your doctor about any concerns you may have.

If you have MASLD, learn as much as you can about your condition. Work closely with your care team. Many medicines can harm your liver. So always tell all your doctors about any medicines you are taking. These include over-the-counter medicines, dietary supplements, herbs, and vitamins.

Other ways to manage the disease include:

• Staying at a weight that is healthy for you.
• Eating healthy foods.
• Getting regular exercise.
• Not drinking alcohol.

Be sure to ask your doctor about recommended vaccines. These include vaccines for viruses that can cause liver disease.

Contact your doctor if you have any symptoms that mean MASLD is getting worse. These are:

• Severe tiredness (fatigue).
• Loss of appetite.
• Weight loss.
• Weakness.
• Extra fluid buildup (fluid retention).
• Bleeding.

• Metabolic dysfunction-associated steatotic liver disease (MASLD) is when fat builds up in your liver because of extra body weight, high blood sugar, high cholesterol, or high blood pressure. It used to be called nonalcoholic fatty liver disease.
• Obesity may be the most common cause of this disease.
• MASLD can happen without causing any symptoms.
• Blood tests and imaging tests, such as a CT scan and ultrasound, can help diagnose it.
• Losing weight and making other lifestyle changes can help control and even reverse this disease.

Here are some tips to help you get the most from a visit to your doctor:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new directions your doctor gives you.
• Know why a new medicine or treatment is prescribed and how it will help you. Also know what the side effects are.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions, especially after office hours and on weekends and holidays.