Semaglutide doubled NASH resolution, fibrosis unclear

Fatty liver disease and its inflammatory form, steatohepatitis, are among the leading causes of chronic liver disease worldwide, and the authors note that no pharmacological therapy is currently approved for them. That leaves weight and metabolic management as the mainstay, which is precisely where GLP-1 receptor agonists such as semaglutide already have an established track record. The open question is whether the metabolic benefit translates into changes in the liver itself: less inflammation, resolution of steatohepatitis, and ideally less scarring. Answering that requires pooling the placebo-controlled trials that took biopsies and blood markers rather than relying on weight change as a proxy.

The authors ran a systematic review and meta-analysis of placebo-controlled randomised trials of subcutaneous semaglutide in adults aged 18 or over with NAFLD or NASH, diagnosed by imaging, histology and/or biochemical markers. PubMed, CENTRAL and Scopus were searched from inception to 15 May 2025. Two assessors independently extracted data and appraised risk of bias with the Cochrane RoB 2 tool, while the certainty of the evidence was graded using GRADE. Effects were pooled with a random-effects model and reported as risk ratios or mean differences with 95% confidence intervals, covering biochemical, histological, metabolic and safety outcomes.

Histologically, semaglutide more than doubled the likelihood of NASH resolution without progression of fibrosis, with a risk ratio of 2.14 (95% CI 1.44 to 3.17; P = .0002). Liver enzymes fell, with aspartate aminotransferase down by a mean of 6.72 U/L (95% CI -11.79 to -1.64; P = .009). Metabolic outcomes improved: weight fell by 6.99% (95% CI -13.92 to -0.06; P = .05) and glycated haemoglobin by 1.29% (95% CI -1.46 to -1.13; P < .00001). Fibrosis stage improvement was not statistically significant (RR 1.14, 95% CI 0.63 to 2.05; P = .67), though the direction favoured semaglutide. Gastrointestinal adverse events and treatment discontinuation were more frequent, while serious adverse events were comparable to placebo.

This consolidates a pattern already visible in individual trials: GLP-1 receptor agonists reliably improve the metabolic and inflammatory features of fatty liver disease, while the harder structural endpoint of fibrosis remains unproven. The distinction matters, because fibrosis stage is what most closely tracks long-term liver outcomes. The wide confidence interval around the fibrosis estimate is as consistent with no effect as with a moderate benefit, which is what the authors mean when they call it uncertain. They explicitly call for longer and adequately powered trials, and the abstract does not report how many trials contributed or how GRADE rated each outcome.

This is a reason to think that semaglutide does more for a fatty, inflamed liver than simply shifting the number on the scales, since steatohepatitis resolution and enzyme falls were measured directly. It is not evidence that scarring reverses; that question is still open. The tolerability trade-off is explicit in the data, with more gut side effects and more people stopping treatment, even though serious adverse events matched placebo. Fatty liver disease is diagnosed and managed clinically, so the practical value here is in understanding what the evidence currently supports rather than in anything you would change unilaterally.