Metabolic dysfunction-associated steatotic liver disease (MASLD) doesn’t always cause obvious symptoms. When symptoms do appear, fatigue and abdominal pain are the most common.

MASLD develops when too much fat builds up in the liver due to metabolic conditions. It’s the most common form of chronic liver disease, affecting about 1 in 3 people worldwide.

Doctors once called MASLD nonalcoholic fatty liver disease (NAFLD). In 2023, experts changed the name to better reflect its root causes and reduce stigma.

Unlike alcohol-associated liver disease (ALD), which develops from excess alcohol use, MASLD doesn’t result from drinking alcohol. Instead, conditions such as obesity or type 2 diabetes contribute to fat buildup in the liver.

MASLD is a long-term condition that can sometimes progress into a more serious stage called metabolic dysfunction-associated steatohepatitis (MASH). At this stage, the liver can become inflamed and damaged.

Catching MASLD early matters. Early detection and treatment may prevent it from progressing, and in some cases, even reverse it.

MASLD doesn’t always cause noticeable symptoms. In fact, most people never develop clear warning signs.

It can take years for fat to build up in the liver to the point where it changes how the organ works. The liver is also resilient and can regenerate. Because of this, it may sustain serious damage before it starts to affect your health. Many people don’t know they have MASLD until it progresses to MASH.

When symptoms do appear in MASLD, they’re usually nonspecific. This means they’re general issues that can happen with many different health conditions.

The most common early signs of MASLD include:

  • fatigue or weakness
  • sharp or aching pain in the upper right side of the abdomen, where the liver sits

For many people, doctors discover MASLD during tests for other reasons. For example, routine bloodwork may show mildly elevated liver enzymes, or imaging tests and a physical exam may reveal an enlarged liver.

MASLD can also cause subtle symptoms that are easy to overlook. Some people may notice:

  • feeling more thirsty than usual
  • trouble sleeping
  • digestive problems, such as indigestion or discomfort
  • brain fog or difficulty concentrating
  • bloating
  • unexplained weight loss
  • itching

MASLD refers specifically to excess fat accumulation in your liver. It doesn’t yet involve inflammation, damage, or scarring (cirrhosis) of your liver. When those things start to happen, MASLD transitions to MASH. As liver damage and inflammation develop, mild symptoms of MASLD can worsen, and new symptoms related to liver failure may appear.

Symptoms of progressing MASLD or MASH can include:

  • fluid buildup in the legs or abdomen
  • confusion and memory impairment
  • loss of appetite
  • jaundice (yellow discoloration of body tissues)
  • easy bleeding and bruising
  • nausea and vomiting

MASLD symptoms are often mild, slow to develop, and nonspecific. In fact, they can take years, or even decades, to appear.

On the other hand, ALD develops when fat builds up in the liver from heavy alcohol use. Symptoms may appear more quickly, especially with very high daily alcohol intake. ALD often causes jaundice (yellowing of the skin and eyes) to develop rapidly. Other common symptoms include fluid buildup in the abdomen, fever, and muscle loss.

Another type of liver inflammation, viral hepatitis, can look similar to MASLD. Some viral strains progress quickly, over just a few days or weeks, while others may remain silent for years.

Like MASLD, viral hepatitis often starts without symptoms. But as the virus progresses, people are more likely to develop noticeable issues early on, such as:

  • nausea
  • vomiting
  • fatigue
  • itching
  • a general feeling of being unwell (malaise)
  • joint pain
  • jaundice (yellowing of the skin and eyes)
  • dark urine
  • pale stool

Catching MASLD early makes a big difference. Early detection and treatment can prevent it from getting worse and, in some cases, reverse it.

Even if you don’t notice symptoms, it’s still important to see your doctor for regular checkups. These visits can help you catch conditions like MASLD before they become serious.

MASLD usually doesn’t become a medical emergency unless it progresses into MASH. At that stage, you may notice warning signs of advanced liver failure. Get medical care right away if you experience:

  • confusion or difficulty thinking clearly
  • severe abdominal swelling
  • new or worsening jaundice (yellowing of the skin and eyes)
  • sudden fatigue with easy bleeding or bruising
  • vomiting blood
  • black, tarry stool
  • fever

If you notice these symptoms, don’t wait. Call your doctor or seek emergency care immediately.

Metabolic dysfunction-associated steatotic liver disease (MASLD) was once called nonalcoholic fatty liver disease (NAFLD). It develops when excess fat builds up in the liver due to metabolic conditions such as type 2 diabetes or obesity.

MASLD doesn’t usually cause obvious symptoms. When symptoms do appear, the most common are fatigue and abdominal pain.

MASLD is often reversible if caught early. Timely treatment can help prevent it from progressing to MASH.