In a landmark NEJM trial, daily semaglutide resolved NASH in 59% of patients (vs. 17% placebo) over 72 weeks, but did not significantly improve liver fibrosis — the key predictor of liver-related death.
59% NASH resolutionBiopsy-confirmed resolution of liver inflammation at the 0.4 mg daily dose, versus 17% on placebo — but fibrosis improvement was not significant
What the researchers found
In a 72-week trial published in the New England Journal of Medicine, semaglutide at 0.4 mg daily achieved NASH resolution (without worsening fibrosis) in 59% of patients, compared to 17% on placebo (P<0.001). This was confirmed by liver biopsy — the gold standard for assessing liver disease.
However, semaglutide did not significantly improve fibrosis: 43% of the 0.4 mg group had fibrosis improvement versus 33% on placebo (P=0.48, not significant). Patients on the highest dose lost an average of 13% of their body weight compared to 1% on placebo. GI side effects were common — 42% experienced nausea and 15% had vomiting at the 0.4 mg dose. A small neoplasm signal was noted (3 malignancies in semaglutide groups vs. 0 on placebo), though no pattern was evident.
Why it matters
This was the first major RCT to test semaglutide specifically for NASH/MASH, published in the world's most prestigious medical journal. The 59% NASH resolution rate at 0.4 mg daily was striking — but the failure to significantly improve fibrosis is the critical limitation, because fibrosis stage is the strongest predictor of liver-related death. This result helped shape the field's understanding that GLP-1 drugs alone may not be enough for advanced liver disease, motivating combination approaches (like adding efruxifermin or resmetirom).
The numbers in context
n=320 · 72 weeks · semaglutide 0.1, 0.2, 0.4 mg daily · NASH resolution: 59% vs 17% placebo (0.4 mg, P<.001) · fibrosis improvement: 43% vs 33% (P=.48, NS) · weight loss: 13% vs 1% · nausea: 42% vs 11% · vomiting: 15% vs 2%
How the study worked
72-week, double-blind, placebo-controlled phase 2 trial. 320 patients with biopsy-confirmed NASH and fibrosis (F1-F3) were randomized 3:3:3:1:1:1 to semaglutide 0.1, 0.2, or 0.4 mg daily or corresponding placebo via subcutaneous injection. Primary endpoint: NASH resolution without fibrosis worsening, assessed by paired liver biopsies. Confirmatory secondary endpoint: improvement of at least one fibrosis stage without NASH worsening. Endpoint analyses for these outcomes were restricted to the 230 patients with F2-F3 fibrosis.
Who was studied
320 patients with biopsy-confirmed NASH and liver fibrosis (F1-F3), including 230 with F2-F3 fibrosis
What this study cannot tell us
Phase 2 trial with 320 patients — adequately powered for the primary endpoint but may be underpowered for fibrosis improvement detection. The semaglutide doses (0.1-0.4 mg daily) differ from the approved weight-loss dose (2.4 mg weekly as Wegovy), making direct comparisons with current clinical practice difficult. The 72-week duration may be insufficient to show fibrosis reversal, which is a slow process. The small neoplasm signal warrants monitoring in larger trials. Daily subcutaneous dosing is more burdensome than the once-weekly formulation used clinically.
How to read the evidence
This is a well-powered, double-blind, placebo-controlled phase 2 RCT published in the NEJM with biopsy-confirmed endpoints — the highest standard for NASH trials. The 'Strong' evidence grade reflects the rigorous design, adequate sample size, and the prestige and peer review standards of the journal.
When this study was published
Published in 2021 in the NEJM, this remains one of the most-cited studies in the NASH/GLP-1 field. It was a pivotal trial that shaped current treatment strategies and combination therapy development. Phase 3 studies and newer combination trials have built directly on these findings.
The bigger picture
This trial established semaglutide as a potential treatment for NASH/MASH but also exposed its limitation — it can resolve liver inflammation but may not adequately address fibrosis on its own. This finding was pivotal in driving the field toward combination therapies, pairing GLP-1 drugs with liver-targeted agents like resmetirom (now FDA-approved as Rezdiffra) or FGF21 analogs like efruxifermin. The study also highlighted the profound impact of GLP-1-mediated weight loss on liver health.
Questions still open
- Would the once-weekly 2.4 mg semaglutide dose (Wegovy) show better fibrosis results than the daily doses tested here?
- Does combining semaglutide with a liver-targeted drug like resmetirom address both inflammation and fibrosis?
- What explains the neoplasm signal — is it real, or a statistical artifact in a small trial?
Common questions
Why did semaglutide fix the inflammation but not the scarring?
Is the semaglutide dose in this trial the same as Ozempic or Wegovy?
Read the original research
A Placebo-Controlled Trial of Subcutaneous Semaglutide in Nonalcoholic Steatohepatitis.
The New England journal of medicine, 384(12), 1113-1124
Citation
Newsome, Philip N; Buchholtz, Kristine; Cusi, Kenneth; Linder, Martin; Okanoue, Takeshi; Ratziu, Vlad; Sanyal, Arun J; Sejling, Anne-Sophie; Harrison, Stephen A. (2021). A Placebo-Controlled Trial of Subcutaneous Semaglutide in Nonalcoholic Steatohepatitis.. The New England journal of medicine, 384(12), 1113-1124. https://doi.org/10.1056/NEJMoa2028395