Against the backdrop of Vietnam's booming e-commerce market, this study explores how social media influencers shape young people's online purchasing intentions. The research addresses a significant research gap regarding the inconsistency in the distribution of influencer attributes and the scarcity of empirical evidence on the parallel mediating roles of attitude and perceived credibility in the Vietnamese market. The study integrates Theory of Planned Behavior (TPB) and Source Credibility Theory. Specifically, three influencer attributes-expertise, credibility, and attractiveness-are considered inputs influencing purchasing decisions through two psychological mediating mechanisms: attitude and perceived credibility. The study employs a quantitative approach, collecting data from 442 eligible respondents aged 16-30 in Vietnam over a six-month period. Data were analyzed using partial least squares (PLS-SEM). All eight hypotheses were accepted, demonstrating a dual mediating mechanism in which expertise and credibility of influence disrupt purchase intention through two mediating variables: attitude and perceived trust level. Attitude, in particular, was the strongest predictor, proving that intrinsic psychological value is more important than the external attributes of the influencer. This result confirms a strong behavioral shift towards content over form among Vietnamese youth, where physical attractiveness has the weakest influence. Because attitude is the primary determinant, businesses need to prioritize content strategy over personal image, as this factor is identified as a crucial element in shaping Gen Z's purchase intention. Market budgets should shift towards consulting experts such as KOCs or evaluators with genuine expertise. This study has several novel aspects compared to previous studies. Previously, research on the theory of planned action and source trust within a single model has been shown to influence influencer activity in purchase intention. Simultaneously, the TPB (Theory of Planned Behavior) has been expanded to focus on mode as a central evaluation mechanism. The study also clarifies the mediating role of influencer attributes indirectly impacting purchase intention through attitude and credibility. The study provides evidence in Vietnam showing that Gen Z prioritizes expertise and trustworthiness over the attractiveness of the influencer.
Thanh et al. (Wed,) studied this question.