THE IMPACT OF CONSUMER–PRODUCT CONGRUENCE ON CONSUMER CONFIDENCE AND BOYCOTT RECOMMENDATION IN INFLUENCER MARKETING: A CASE STUDY OF HA LINH OFFICIAL AND HOA LINH PHARMACEUTICALS

Influencer marketing has become increasingly influential in shaping consumer perceptions in emerging markets such as Vietnam, where livestream-based product reviews are widespread. Despite this growth, limited empirical research has examined how consumer–product congruence influences consumer confidence and boycott recommendation within influencer marketing contexts. This study investigates the mechanisms through which consumer–product congruence influences recommendation credibility and attitude toward the recommendation, which subsequently shape consumer confidence and boycott recommendation, using the case of Ha Linh Official and Hoa Linh Pharmaceuticals. A quantitative research design was employed, with data collected through a structured online questionnaire from 250 consumers familiar with both the influencer and the brand. Data were analyzed using SPSS for descriptive statistics and Partial Least Squares Structural Equation Modeling with SmartPLS to test the proposed relationships. The findings reveal that consumer–product congruence positively influences recommendation credibility, which directly enhances consumer confidence and indirectly strengthens confidence through attitude toward the recommendation, with attitude serving as a partial mediating mechanism. Furthermore, attitude toward the recommendation negatively affects boycott recommendation, indicating that more favourable attitudes reduce consumers' tendency to recommend boycotts. These results contribute to influencer marketing literature by clarifying the role of congruence in shaping both supportive and resistance-related consumer responses, and offer practical implications for brands and influencers seeking to build credibility, strengthen trust, and mitigate boycott-related risks.