INTRODUCTION: Drug alerts aimed at both people who use drugs and health workers help to prevent acute harms from unpredictable illicit drug markets and by equipping health workers to handle unusual drug events and share vital information with service users. However, there has never been an alert produced for anabolic-androgenic steroids (AAS), an important class of illicit drugs. We report on the development, implementation and community receptivity of the first-ever AAS community drug alert. METHODS: Based on findings from samples collected during the first month of an AAS checking trial conducted by drug checking service CheQpoint, we identified contamination in two oxandrolone samples, which prompted issuing of the first-ever AAS community notice. Drawing on digital ethnographic techniques, we collected and analysed social media comments on the notice to assess AAS community perceptions and the broader impact of this harm reduction initiative. RESULTS: The Instagram post by CheQpoint reached 1376 users, with 3429 impressions and 87 interactions. Community feedback indicated receptivity to the notice, with several people in the community recognising the prevalence of AAS adulteration. Responses highlighted the need for more thorough testing and indication of sample content, given the perception of a growing number of new people using AAS. DISCUSSION AND CONCLUSIONS: This study, the first to describe a community notice for illicit market AAS, reveals a strong demand for harm reduction interventions. We call for the urgent expansion of drug-checking services to provision for AAS and, thus, provide equitable health support to address systemic gaps for this group.