BACKGROUND: Alcohol use disorder accounts for 5% of deaths worldwide annually, and there is an urgent need for new therapeutic interventions. Preclinical and initial human studies indicate that the GLP-1 receptor agonist semaglutide might reduce alcohol drinking. This study evaluated the efficacy of semaglutide once-weekly in treatment-seeking patients with alcohol use disorder and comorbid obesity.

METHODS: In a 26-week, single-centre, randomised, double-blinded, placebo-controlled trial, treatment-seeking participants with moderate to severe alcohol use disorder and comorbid obesity were assigned (1:1) to receive once-weekly semaglutide (2·4 mg subcutaneously) or placebo (saline subcutaneously), in addition to standard cognitive behavioural therapy. The primary endpoint was a reduction in the number of heavy drinking days assessed after 26 weeks of intervention, analysed with an ANCOVA model. Analysis adhered to the intention-to-treat principle, and missing outcome data were addressed using multiple imputations. Safety was assessed in all treated patients. The trial is registered at ClinicalTrials.govNCT05895643, and is complete.

FINDINGS: From June 10, 2023, to Feb 4, 2025, 108 participants (53 women and 55 men) were enrolled, with 54 participants in each of the semaglutide and placebo treatment groups, and all were included in the data analysis. Overall, 88 participants (81%) completed the full intervention. Semaglutide was associated with a reduction in heavy drinking days (-41·1 percentage points from baseline, 95% CI -48·7 to -33·5) compared with placebo (-26·4, -34·1 to -18·6; estimated treatment difference -13·7 percentage points, -22·0 to -5·4; p=0·0015), and had substantial effects on multiple secondary alcohol-related and somatic outcomes. Adverse events were transient, generally mild to moderate gastrointestinal effects, and occurred more frequently in the semaglutide group.

INTERPRETATION: Semaglutide showed robust therapeutic effects in treatment-seeking participants with obesity and alcohol use disorder and this trial supports previous preclinical and clinical findings suggesting GLP-1 receptor agonists as a potential novel treatment target for alcohol use disorder.

FUNDING: The Research Foundation, Mental Health Services (Capital Region of Denmark), the Novo Nordisk Foundation, the Novavi Foundation, the Hartmann Foundation, and the Augustinus Foundation.