Influencer Authenticity and Homophily in Instagram Live Commerce: A Stimulus–Organism–Response Approach to Online Trust and Purchase Intention in Indonesia’s Local Skincare Industry

The massive growth of Instagram Live Commerce has encouraged local skincare brands in Indonesia to invest heavily in influencer marketing. However, high influencer engagement does not always lead to purchase intention, creating an engagement–conversion gap. This study examines the effects of influencer authenticity and influencer homophily on online trust and purchase intention in Indonesia's local skincare industry using the Stimulus–Organism–Response (S–O–R) framework. A quantitative cross-sectional survey was conducted with 220 valid Generation Z respondents, and the data were analysed using Partial Least Squares Structural Equation Modeling (PLS-SEM). The results show that all proposed hypotheses were supported. Influencer authenticity has the strongest total effect on purchase intention (β = 0.420), followed by influencer homophily (β = 0.264). Both influencer characteristics significantly strengthen online trust, which in turn increases purchase intention and partially mediates their effects on consumers' purchase intention. The findings suggest that authentic and relatable influencers are more effective in building consumer trust and encouraging purchase intention during Instagram Live sessions. This study provides empirical evidence on influencer marketing in Indonesia's local skincare industry and offers practical insights for brands to prioritise trust when selecting influencers.