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Zepbound for fatty liver (MASH): trial results and approval status

Updated Sep 30, 2026. Numbers in brackets link to the source each fact comes from.

Zepbound is not FDA-approved to treat fatty liver disease. Its label lists two uses, weight reduction and obstructive sleep apnea [8] [9]. The evidence for tirzepatide in MASH comes from a mid-stage trial with encouraging biopsy results, while Wegovy is the GLP-1 that carries a MASH approval on its label [10].

MASLD and MASH in plain terms

MASLD is the newer name for nonalcoholic fatty liver disease: extra fat builds up in the liver for reasons other than heavy drinking [1]. MASH, formerly called NASH, is the form where the liver is also inflamed and damaged. That damage can cause scarring, called fibrosis [2]. Trials in this area measure fibrosis in stages from a liver biopsy, and the drug studies below enrolled people with stage 2 or 3 scarring, which the Wegovy label calls moderate to advanced [10].

What SYNERGY-NASH tested

SYNERGY-NASH was a phase 2 dose-finding trial [3]. Adults with biopsy-confirmed MASH and stage 2 or 3 fibrosis took weekly tirzepatide at 5, 10 or 15 mg, or a placebo, for 52 weeks [3]. It randomized 190 people, and 157 had a week-52 biopsy that could be read; missing results were filled in assuming they would look like the placebo group [4].

Results at 52 weeks, from the published abstract [5] [6]:

Group MASH resolved, fibrosis not worse Fibrosis improved one stage or more, MASH not worse
Placebo 10% [5] 30% [6]
Tirzepatide 5 mg 44% [5] 55% [6]
Tirzepatide 10 mg 56% [5] 51% [6]
Tirzepatide 15 mg 62% [5] 51% [6]

The authors concluded that tirzepatide beat placebo on the main goal, MASH resolution, and wrote that larger and longer trials are needed to judge whether it works and is safe as a MASH treatment [7]. None of these results appear on the Zepbound label, which does not mention MASH or fatty liver at all.

Why Wegovy has a MASH approval and Zepbound does not

Wegovy’s approval came from a larger phase 3 trial, ESSENCE [15]. It assigned 1,197 people with stage 2 or 3 fibrosis to semaglutide 2.4 mg or placebo for a planned 240 weeks; the approval rests on an interim look at the first 800 patients at week 72 [15]. In that analysis, steatohepatitis resolved without worse fibrosis in 62.9% on semaglutide against 34.3% on placebo, and fibrosis improved without worse steatohepatitis in 36.8% against 22.4% [16].

Novo Nordisk announced the approval in August 2025 [14]. The label spells out the terms:

  • Who: adults with noncirrhotic MASH and moderate to advanced fibrosis, stages F2 to F3 [10].
  • Accelerated approval: granted on improvement in MASH and fibrosis, and continued approval may depend on a confirmatory trial showing clinical benefit [10] [11].
  • Dose: 2.4 mg once weekly as the maintenance dose [12].
  • Form: the injection. The label says safety has not been established for Wegovy tablets or the 7.2 mg injection in patients with MASH [13].

Resmetirom (Rezdiffra) is a non-GLP-1 option: the FDA approved it for the same kind of noncirrhotic MASH with moderate to advanced scarring in March 2024 [20].

What this means for coverage

MASH is on Wegovy’s label but not on Zepbound’s, and that difference follows the prescription into coverage.

  • Medicare. CMS says the MASH indication, like type 2 diabetes and moderate to severe sleep apnea, is eligible for Part D coverage [17]. People with those diagnoses cannot use the Medicare GLP-1 Bridge, even if their own Part D plan does not cover the drug for that condition [18]. See our Medicare GLP-1 Bridge guide.
  • Zepbound with MASH. A Zepbound prescription has to rest on one of its two labeled uses: weight reduction in adults with obesity, or overweight with a weight-related condition, or moderate to severe sleep apnea with obesity [8] [9]. Prescribing it for the liver itself would be off-label.
  • Not both. The Zepbound label says not to combine it with any other GLP-1 medicine, which includes Wegovy [19].

Whether any of these medicines suits your liver is a decision for a hepatologist or the prescriber who has your biopsy or scan results.

Sources

  1. Nonalcoholic fatty liver disease, or NAFLD (also referred to as metabolic dysfunction-associated steatotic liver disease, or MASLD), is a condition in which excess fat builds up in your liver niddk.nih.gov, read Sep 27, 2026.
  2. NASH is the form of NAFLD in which you have inflammation of the liver and liver damage, in addition to fat in your liver. The inflammation and liver damage of NASH can cause fibrosis, or scarring, of the liver. niddk.nih.gov, read Sep 27, 2026.
  3. We conducted a phase 2, dose-finding, multicenter, double-blind, randomized, placebo-controlled trial involving participants with biopsy-confirmed MASH and stage F2 or F3 (moderate or severe) fibrosis. Participants were randomly assigned to receive once-weekly subcutaneous tirzepatide (5 mg, 10 mg, or 15 mg) or placebo for 52 weeks. pubmed.ncbi.nlm.nih.gov, read Sep 27, 2026.
  4. Among 190 participants who had undergone randomization, 157 had liver-biopsy results at week 52 that could be evaluated, with missing values imputed under the assumption that they would follow the pattern of results in the placebo group. pubmed.ncbi.nlm.nih.gov, read Sep 27, 2026.
  5. The percentage of participants who met the criteria for resolution of MASH without worsening of fibrosis was 10% in the placebo group, 44% in the 5-mg tirzepatide group (difference vs. placebo, 34 percentage points; 95% confidence interval [CI], 17 to 50), 56% in the 10-mg tirzepatide group (difference, 46 percentage points; 95% CI, 29 to 62), and 62% in the 15-mg tirzepatide group (difference, 53 percentage points; 95% CI, 37 to 69) (P<0.001 for all three comparisons). pubmed.ncbi.nlm.nih.gov, read Sep 27, 2026.
  6. The percentage of participants who had an improvement of at least one fibrosis stage without worsening of MASH was 30% in the placebo group, 55% in the 5-mg tirzepatide group (difference vs. placebo, 25 percentage points; 95% CI, 5 to 46), 51% in the 10-mg tirzepatide group (difference, 22 percentage points; 95% CI, 1 to 42), and 51% in the 15-mg tirzepatide group (difference, 21 percentage points; 95% CI, 1 to 42). pubmed.ncbi.nlm.nih.gov, read Sep 27, 2026.
  7. Larger and longer trials are needed to further assess the efficacy and safety of tirzepatide for the treatment of MASH. pubmed.ncbi.nlm.nih.gov, read Sep 27, 2026.
  8. to reduce excess body weight and maintain weight reduction long term in adults with obesity or adults with overweight in the presence of at least one weight-related comorbid condition. dailymed.nlm.nih.gov, read Sep 27, 2026.
  9. to treat moderate to severe obstructive sleep apnea (OSA) in adults with obesity. dailymed.nlm.nih.gov, read Sep 27, 2026.
  10. for the treatment of noncirrhotic metabolic dysfunction-associated steatohepatitis (MASH), formerly known as nonalcoholic steatohepatitis (NASH), with moderate to advanced liver fibrosis (consistent with stages F2 to F3 fibrosis) in adults. This indication is approved under accelerated approval based on improvement of MASH and fibrosis. dailymed.nlm.nih.gov, read Sep 27, 2026.
  11. Continued approval for this indication may be contingent upon the verification and description of clinical benefit in a confirmatory trial. dailymed.nlm.nih.gov, read Sep 27, 2026.
  12. The recommended maintenance dosage of WEGOVY injection for the treatment of noncirrhotic MASH with moderate to advanced liver fibrosis in adults is 2.4 mg injected subcutaneously once weekly. dailymed.nlm.nih.gov, read Sep 27, 2026.
  13. The safety of WEGOVY tablets and WEGOVY 7.2 mg injection have not been established in pediatric patients or patients with MASH. dailymed.nlm.nih.gov, read Sep 27, 2026.
  14. Novo Nordisk today announced that the US Food and Drug Administration (FDA) has approved an additional indication for Wegovy ® (semaglutide 2.4 mg) based on a supplemental New Drug Application (sNDA) for treatment of noncirrhotic metabolic dysfunction-associated steatohepatitis (MASH) in adults with moderate to advanced liver fibrosis (consistent with stages F2 to F3 fibrosis), in combination with a reduced calorie diet and increased physical activity. novonordisk.com, read Sep 27, 2026.
  15. In this ongoing phase 3, multicenter, randomized, double-blind, placebo-controlled trial, we assigned 1197 patients with biopsy-defined MASH and fibrosis stage 2 or 3 in a 2:1 ratio to receive once-weekly subcutaneous semaglutide at a dose of 2.4 mg or placebo for 240 weeks. The results of a planned interim analysis conducted at week 72 involving the first 800 patients are reported here (part 1). pubmed.ncbi.nlm.nih.gov, read Sep 27, 2026.
  16. Resolution of steatohepatitis without worsening of fibrosis occurred in 62.9% of the 534 patients in the semaglutide group and in 34.3% of the 266 patients in the placebo group (estimated difference, 28.7 percentage points; 95% confidence interval [CI], 21.1 to 36.2; P<0.001). A reduction in liver fibrosis without worsening of steatohepatitis was reported in 36.8% of the patients in the semaglutide group and in 22.4% of those in the placebo group pubmed.ncbi.nlm.nih.gov, read Sep 27, 2026.
  17. Type 2 diabetes, moderate to severe obstructive sleep apnea, and noncirrhotic metabolic dysfunction-associated steatohepatitis (MASH) indications are eligible for Part D coverage. cms.gov, read Sep 27, 2026.
  18. If a beneficiary has a diagnosis of type 2 diabetes, moderate to severe obstructive sleep apnea, or noncirrhotic MASH with moderate to advanced liver scarring (fibrosis) (formerly known as NASH), they are not eligible for coverage under the Medicare GLP-1 Bridge, regardless of whether their current Part D plan covers a GLP-1 drug for that condition. cms.gov, read Sep 27, 2026.
  19. ZEPBOUND contains tirzepatide. Coadministration with other tirzepatide-containing products or with any glucagon-like peptide-1 (GLP-1) receptor agonist is not recommended. dailymed.nlm.nih.gov, read Sep 27, 2026.
  20. Today, the U.S. Food and Drug Administration approved Rezdiffra (resmetirom) for the treatment of adults with noncirrhotic non-alcoholic steatohepatitis (NASH) with moderate to advanced liver scarring (fibrosis), to be used along with diet and exercise. fda.gov, read Sep 27, 2026.

This page reports what official sources say; it is not medical advice. Medical disclaimer.