It’s a liver condition potentially impacting millions of Americans, but, due to its relative lack of symptoms in early stages, many don’t even know they have it.

“Roughly 40% of the adult population in the United States is living with this condition,” said Jonathan Stine, Penn State Health’s Liver Center Director of Research and an associate professor of medicine and public health sciences, referring to what was once known as fatty liver disease. And because there are so few symptoms, many do not even suspect they have a problem.

While the name has changed — to steatotic liver disease — the danger has not, Stine said.

In a global effort to destigmatize and clarify diagnosis, experts renamed and reclassified the condition, which includes several subtypes, said Stine. Under the steatotic liver disease umbrella are metabolic dysfunction-associated steatotic liver disease (MASLD) and alcohol-associated liver disease.

The most potentially deadly category of MASLD is called MASH, short for metabolic dysfunction-associated steatohepatitis.

A diagnosis of MASH, which accounts for about 14% of all non-alcohol-related cases of liver disease, “means that patients have fat in their liver related to abnormal metabolism,” Stine said. Over time, that fat results in inflammation, often followed by scar tissue, “then cirrhosis, liver cancer and potentially the need for a life-saving liver transplantation.”

One of the biggest dangers of MASH is that because it produces no symptoms in its early stages, it’s often discovered too late, when liver damage is already severe, Stine said.

An international report published June 4 in The Lancet Regional Health – Europe underscores the rising global prevalence of MASH and warns of its growing burden. The authors call for doubling current diagnosis rates, citing an urgent need to catch the disease earlier, as MASH-related liver failure and complications become increasingly common and severe.

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Early diagnosis is crucial, Stine said, “because we don’t want somebody to end up in the hospital with complications of liver disease and find out for the first time” that they’ve been suffering from the condition for ages without detection.

He advises that people at risk of developing MASH — especially those with high cholesterol, high blood pressure, diabetes, obesity or a family history of liver disease — should urge their primary care doctors to check their liver enzymes during routine blood work. Abnormal results should prompt imaging studies, such as a specialized ultrasound like the FibroScan, which, Stine said, measures both fat and how stiff a liver might be. A stiff liver indicates the presence of scar tissue, increasing the seriousness of the diagnosis.

Because symptoms can be elusive, Stine suggested that increased diagnosis can only come through an effort at many levels — with primary care doctors and specialists, scientists developing new testing methods and patients themselves all involved.

Raising awareness is key: “Roughly nine out of 10 patients that are diagnosed have told us they’re not even aware that MASH and MASLD exist.”

Additionally, more specialized care is needed. “Who is going to own the care of these patients? There’s one liver doctor for every 40,000 patients with steatotic liver disease. So clearly, the specialists are a little overwhelmed.”

He acknowledged that primary care physicians are also crunched for time.

“They have to address so many different problems in a very short clinical visit, so we have to just really figure out how to make it easy on them, and then specialists need to continue to do their part and provide expert, comprehensive care”

Who’s most at risk?

People with obesity or type 2 diabetes are at risk, but the condition can also impact those with a “normal” body weight and BMI, Stein said.

Also at risk, he said, are women with polycystic ovarian syndrome, “due to issues of insulin resistance.”

Family history also plays a powerful role. “There are at least six main genes responsible for this condition,” he added. “We currently recommend anybody over age 40 who has a first-degree relative with MASH should get screened.”

Hope on the horizon

For years, lack of treatment options made the chances of a positive prognosis quite bleak.

But in March 2024, the Food and Drug Administration approved resmetirom, which “treats low thyroid activity inside the liver,” Stein said, helping patients to return to a healthier metabolism.

Resmetirom is a thyroid hormone receptor beta agonist, meaning it works by targeting and activating a protein involved in regulating liver fat metabolism and inflammation, according to Caymen Chemical, a Michigan-based biotechnology company.

Over time, resmetirom can even reverse scar tissue, something once thought irreversible.

A second treatment, semaglutide, known for its role in weight loss and the treatment of type 2 diabetes, is currently under FDA review as a potential option. It’s expected to be approved by the end of the year, Stein said.

While semaglutide, sold under the brand names Ozempic, Wegovy and Rybelsus, would require a higher dose than what is used to treat type 2 diabetes, it “has been shown to be effective for reversing scar tissue and getting fat out of the liver,” Stine said.

For patients who are unfamiliar with MASH or unsure what to ask for, Stine offered this advice: “Get interested. Ask questions.” Bring up concerns during your next doctor’s visit because if the condition is detected early enough, outcomes can be improved dramatically via lifestyle changes.

Stine’s team recommends a Mediterranean diet, rich in lean proteins, beans, olive oil and deep-sea fish.

Exercise, too, is key.

“We do routinely recommend folks get about 150 minutes per week of moderate intensity activity,” he said, like walking or light cycling. Add in resistance training twice a week, he noted, and improvements can be significant.

First Published: June 28, 2025, 1:00 a.m.
Updated: June 28, 2025, 5:55 p.m.