Virtual influencers are increasingly becoming a novel tool in brand promotion. Although numerous studies had examined the marketing effects of virtual influencers, their performance in social-benefit appeal contexts remains underexplored. This study focuses on this specific context to investigate the impact of virtual influencers promoting social-benefit products on consumers’ purchase intentions. Across three experiments, we find that in advertisements with social-benefit appeals, virtual influencers (compared to human influencers) reduce consumers’ purchase intentions, while no significant difference was observed in personal-benefit appeal contexts. Further analysis reveals that this negative effect stems from consumers’ perception of virtual influencers as out-group members, which diminishes their perception of common in-group identity with the virtual endorser. Additionally, the study finds that increasing consumers’ perceived human-virtual being coexistence or employing informational (vs. normative) persuasion strategies can mitigate the negative impact of virtual influencers. This research not only extends the application scope of virtual influencers across different advertising appeal contexts and explores the underlying mechanisms of their effects, but also proposes strategies to enhance the marketing effectiveness of virtual influencers, providing guidance for brand management practice.