Fatty liver disease linked to metabolic health is now called MASLD, and its inflammatory form is MASH. Weight loss is the core treatment, and Wegovy (semaglutide) gained FDA accelerated approval in 2025 for MASH with moderate to advanced scarring.
Fatty liver disease tied to metabolic health is now called MASLD (metabolic dysfunction-associated steatotic liver disease), and its more serious inflammatory form is MASH (metabolic dysfunction-associated steatohepatitis). Weight loss is the foundation of treatment, and GLP-1 medications have produced some of the strongest liver results seen in clinical trials. In August 2025, the FDA granted accelerated approval to Wegovy (semaglutide) for adults with MASH and moderate to advanced liver scarring, while tirzepatide's liver data are promising but earlier stage.
In 2023, three large international liver associations led a consensus process with 236 panelists from 56 countries to rename fatty liver disease. Respondents felt the older terms were flawed, and the words "nonalcoholic" and "fatty" were considered stigmatizing by 61 percent and 66 percent of respondents, respectively.
The resulting names, published in Hepatology and the Journal of Hepatology, are:
| New term | Older term | What it means |
|---|---|---|
| Steatotic liver disease (SLD) | (umbrella term) | Excess fat in the liver from any cause |
| MASLD | NAFLD | Liver fat plus at least 1 of 5 cardiometabolic risk factors |
| MASH | NASH | MASLD with liver inflammation (steatohepatitis) |
| MetALD | (new) | MASLD in people who also drink more alcohol (140 to 350 g per week for women, 210 to 420 g per week for men) |
The practical change is that the diagnosis is now defined by what is present (metabolic risk factors) rather than what is absent (heavy alcohol use). It also ties the diagnosis directly to cardiometabolic health, the same territory where weight management works.
MASLD starts with excess fat in the liver. The greater concern is MASH, the inflammatory form, and the fibrosis (scar tissue) that can come with it. Clinical trials and FDA approvals in this area focus on people with stage F2 or F3 fibrosis, described as moderate to advanced scarring, without cirrhosis.
The FDA describes MASH as a serious liver disease and notes that its prevalence is expanding. Because the disease typically progresses slowly, the FDA has accepted liver biopsy findings as an early (surrogate) measure, with longer-term confirmation still required. The ESSENCE trial, for example, is designed to run 240 weeks.
Before any medication was approved, the main evidence for treatment came from lifestyle studies. A 2015 study in Gastroenterology followed 293 people with biopsy-confirmed NASH (now called MASH) who were counseled on diet and activity for 52 weeks, with liver biopsies at the start and end.
The results showed a clear dose-response pattern:
The authors concluded that the highest rates of improvement occurred with weight loss of 10 percent or more. The challenge, as the study itself showed, is that most people did not reach that level through lifestyle change alone.
ESSENCE is an ongoing phase 3 trial that enrolled 1,197 adults with biopsy-confirmed MASH and stage F2 or F3 fibrosis. An interim analysis of the first 800 participants at week 72, published in the New England Journal of Medicine in 2025, found:
Gastrointestinal side effects were more common with semaglutide. These figures are group averages, and individual responses vary.
SYNERGY-NASH was a smaller phase 2 trial of 190 participants with MASH and F2 or F3 fibrosis, treated for 52 weeks. MASH resolution without worsening fibrosis occurred in 10 percent of the placebo group and in 44, 56 and 62 percent across the three tirzepatide dose groups. Improvement of at least one fibrosis stage occurred in 30 percent with placebo and 51 to 55 percent with tirzepatide. The authors wrote that larger and longer trials are needed.
Wegovy (semaglutide). On August 15, 2025, the FDA approved Wegovy injection to treat noncirrhotic MASH with moderate to advanced fibrosis in adults, alongside diet and exercise. This was an accelerated approval, which the FDA explains is based on a surrogate endpoint (liver biopsy findings), with further data required to confirm clinical benefit. The Wegovy label notes that Wegovy tablets are not indicated for MASH.
Resmetirom. The first medication the FDA approved for this condition was Rezdiffra (resmetirom), in March 2024, also under accelerated approval for noncirrhotic disease with moderate to advanced scarring. It works differently from GLP-1 medications.
Tirzepatide. Tirzepatide is not FDA-approved for MASH. Using it for that purpose would be off-label, and the current evidence comes from a phase 2 trial.
Compounded products. Compounded semaglutide and compounded tirzepatide are not FDA-approved for any use and were not the products tested in these trials. Any decision about a GLP-1 medication, and its dosing, is made by a prescriber who knows your liver test results and history.
MASLD is the current medical name for fatty liver disease linked to at least one cardiometabolic risk factor. It replaced the term NAFLD in 2023. MASH is the inflammatory form that can lead to scarring.
In a 52-week lifestyle study, weight loss of 5 percent or more was linked with MASH resolution in 58 percent of participants, and 10 percent or more with resolution in 90 percent and fibrosis regression in 45 percent. These are study results, not predictions for any individual.
Wegovy injection is approved under accelerated approval for adults with noncirrhotic MASH and moderate to advanced fibrosis. It is not approved for simple liver fat without that degree of disease, and continued approval depends on confirmatory trial results.
In ESSENCE, fibrosis improved without worsening inflammation in 36.8 percent of people on semaglutide versus 22.4 percent on placebo over 72 weeks. That means improvement was more common, not universal. Longer follow-up is still underway.
If a blood test or scan has suggested fatty liver, a licensed provider can help you understand what stage you may be at, what further testing makes sense, and whether weight-focused treatment is appropriate for you. Our guides on nutrition on a GLP-1 program and visceral fat offer related background. This article is educational and does not determine eligibility for any treatment.
Written by the NewDay Wellness editorial team from the sources above and checked against them before publication, and medically reviewed by Dr. Sean Arora and Dr. Shannon Arora of Arora Health & Aesthetics; see our editorial standards. This article is educational and does not diagnose conditions, establish eligibility for any medication, or replace care from a licensed provider. Compounded medications are not FDA-approved.
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