Influencer Credibility, Brand Trust, and Impulsive Purchase Intention in Social Commerce: A Cross-Generational Investigation Across Emerging Markets

Social commerce platforms integrating peer recommendation, influencer content, and seamless in-app purchasing have fundamentally restructured consumer decision-making processes across emerging markets, where mobile-first internet adoption and youthful demographic profiles amplify the behavioral reach of influencer-mediated commerce. Despite rapid market growth, the mechanisms through which influencer credibility translates into brand trust, and subsequently into impulsive purchase intention, remain incompletely theorized and insufficiently tested across generational cohorts and cultural contexts in developing economies. This study develops and tests an integrated model grounded in the Elaboration Likelihood Model, Source Credibility Theory, and Stimulus-Organism-Response framework to examine how influencer expertise, trustworthiness, and parasocial relationship intensity shape brand trust and impulsive purchase intention among Generation Z and Millennial consumers in Egypt, Indonesia, and Nigeria. Drawing on survey data from 624 active social commerce users and employing covariance-based structural equation modeling (CB-SEM) with multi-group analysis, the study finds that influencer trustworthiness exerts the strongest effect on brand trust (beta = 0.49, p < 0.001), which fully mediates the relationship between all influencer credibility dimensions and impulsive purchase intention. Parasocial relationship intensity significantly moderates the trustworthiness-brand trust relationship (beta = 0.26, p < 0.01). Generation Z consumers demonstrate significantly stronger parasocial relationship effects than Millennials, while cultural tightness-looseness moderates the relative weight of expertise versus trustworthiness pathways across the three national samples. The study contributes to social commerce, consumer behavior, and influencer marketing literatures and offers actionable recommendations for brand managers, platform operators, and marketing regulators in emerging market contexts.