Wegovy Approved for MASH: What the ESSENCE Trial Showed
The first GLP-1 approved for liver disease. ESSENCE trial results, eligibility by fibrosis stage, and how it compares to resmetirom.
On August 15, 2025, the FDA granted accelerated approval to Wegovy (semaglutide) for the treatment of metabolic dysfunction-associated steatohepatitis — MASH — in adults with moderate-to-advanced liver fibrosis (stages F2–F3), without cirrhosis. It's the first GLP-1 medication approved for any liver indication, and the second drug ever approved for MASH after resmetirom (Rezdiffra) in 2024.
MASH — formerly called NASH — affects approximately 14.9 million U.S. adults. It's a progressive form of fatty liver disease that can silently advance to cirrhosis, liver cancer, or liver failure requiring transplant. Until recently, there was nothing to offer patients except "lose weight." Now there are two pharmacologic options, and for patients already on GLP-1 therapy for obesity or diabetes, one of them overlaps with what they're already taking.
What Is MASH?
MASH (metabolic dysfunction-associated steatohepatitis) is a severe form of metabolic dysfunction-associated steatotic liver disease (MASLD). It develops when fat accumulates in the liver, triggering inflammation ("steato-hepatitis" means fat + liver inflammation) and progressive scarring (fibrosis). Left unmanaged, MASH can progress through stages:
- F0–F1: No or minimal fibrosis (MASLD/MASH without significant scarring)
- F2: Moderate fibrosis (significant scarring, portal expansion)
- F3: Advanced fibrosis (bridging fibrosis)
- F4: Cirrhosis (extensive scarring, liver dysfunction)
MASH is closely tied to obesity, type 2 diabetes, and metabolic syndrome. Estimates suggest 1 in 3 people with overweight or obesity have some degree of MASLD, and a meaningful fraction progress to MASH.
MASH is typically asymptomatic until the disease has advanced significantly. Early and even moderate stages cause no symptoms. It's often detected incidentally on imaging or through abnormal liver enzymes during routine bloodwork, then confirmed by noninvasive tests (VCTE / FibroScan, MRE, ELF blood test) or — in ambiguous cases — liver biopsy.
The ESSENCE Trial
FDA approval was based on Part 1 of the Phase 3 ESSENCE trial (NCT04822181), a randomized, double-blind, placebo-controlled study in adults with biopsy-confirmed MASH and stage F2 or F3 fibrosis. Participants received either semaglutide 2.4 mg weekly (n=534) or placebo (n=266) for 72 weeks, alongside standard lifestyle interventions.
At 72 weeks:
- ~63% of semaglutide patients achieved resolution of steatohepatitis without worsening fibrosis (vs. 34% placebo) — a 29-percentage-point difference.
- 37% achieved improvement in fibrosis without worsening steatohepatitis (vs. 22% placebo) — a 14-percentage-point difference.
- 33% achieved both endpoints (vs. 16% placebo).
- 88% of patients maintained the 2.4 mg target dose through week 72.
Results were published in the New England Journal of Medicine in 2025.
Part 2 Is Still Running
Accelerated approval means the FDA has authorized the drug based on a surrogate endpoint (histologic improvement) that is reasonably likely to predict clinical benefit. Part 2 of ESSENCE is ongoing and will extend to 240 weeks. It's designed to show whether semaglutide reduces hard clinical events — progression to cirrhosis, liver transplant, liver-related death — compared to placebo. Results are expected in 2029.
Who Qualifies
- Adults with MASH
- Moderate-to-advanced fibrosis (F2 or F3)
- Not cirrhosis (F4) — Wegovy for MASH is not approved for patients with cirrhosis
- Confirmed via liver biopsy or noninvasive tests — AASLD guidance (November 2025) accepts VCTE (8–15 kPa), MRE (3.1–4.4 kPa), or ELF (9.2–10.5) for most patients without requiring biopsy
The AASLD updated their practice guidance in November 2025 to reflect semaglutide's new MASH indication. They specifically note that liver biopsy is "impractical and unnecessary for most patients" when noninvasive test values fall within defined ranges.
How It Compares to Resmetirom
Resmetirom (Rezdiffra) was the first MASH drug, approved in March 2024. It's a thyroid hormone receptor-beta agonist — a completely different mechanism from semaglutide. Some key differences:
| Feature | Semaglutide (Wegovy) | Resmetirom (Rezdiffra) |
|---|---|---|
| Mechanism | GLP-1 receptor agonist | Thyroid hormone receptor-β agonist |
| Format | Weekly injection | Daily oral |
| MASH resolution (trial) | ~63% | ~26–30% |
| Weight loss | Substantial (~15%) | Minimal |
| Also treats | Obesity, T2D, cardiovascular, OSA | MASH only (currently) |
For MASH patients who also have obesity, type 2 diabetes, or established cardiovascular disease, semaglutide's one-drug-multiple-benefits profile is often appealing. For MASH patients without significant weight or metabolic issues — rarer but not unheard of — resmetirom's oral format and narrower side effect profile may be preferable.
Some hepatologists expect combination therapy will become standard: one drug targeting the metabolic drivers (semaglutide) plus another targeting liver-specific pathways (resmetirom or future pipeline drugs). Research is ongoing.
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If You Already Take a GLP-1
Many people on semaglutide for obesity or type 2 diabetes also have undiagnosed MASH. Large epidemiology estimates suggest significant overlap. If you're on Wegovy or Ozempic and have risk factors — type 2 diabetes, obesity, elevated liver enzymes, metabolic syndrome — consider asking your primary care provider or endocrinologist about:
- FibroScan (VCTE): A quick, noninvasive liver stiffness measurement
- ELF blood test: Three biomarkers combined to estimate fibrosis
- MRE (magnetic resonance elastography): More accurate but more expensive
You may already be treating MASH without knowing it. The histologic improvements seen in ESSENCE occurred regardless of whether patients had a formal MASH diagnosis at baseline — what mattered was that they had the disease. Confirming it could change how you and your hepatologist think about long-term monitoring.
What About Cirrhosis?
Wegovy for MASH is not approved for patients with cirrhosis (F4). Patients with compensated cirrhosis who are receiving semaglutide for another FDA-approved indication (obesity, T2D, CV disease) should be monitored carefully, per AASLD guidance. Those with decompensated cirrhosis generally should not be on GLP-1 therapy.
Questions to Ask Your Hepatologist or PCP
- Given my risk factors, should I be screened for MASH with a FibroScan or ELF test?
- If I have MASH, what stage am I at — and does that qualify for semaglutide treatment?
- If I'm already on semaglutide for weight loss or diabetes, does that change the monitoring plan?
- Would combination therapy with resmetirom make sense for my case?
- How often should liver function and fibrosis markers be reassessed during treatment?
The Bottom Line
Wegovy for MASH is a significant expansion of what GLP-1 medications can do. For the large population of patients with both metabolic dysfunction and liver disease — which is most MASH patients — it's a one-medication answer to two problems. The accelerated approval means long-term clinical benefit on hard endpoints (cirrhosis, transplant, death) is still being confirmed through ESSENCE Part 2. But the histologic evidence at 72 weeks is strong, and the AASLD has already updated practice guidance to integrate it. If you're on a GLP-1 already and have never been screened for MASH, it may be worth asking.