Key Opinion Leaders versus Key Opinion Consumers: How Trust, Product Attitude, and Perceived Effectiveness Shape Purchase Intention on Social Media

Influencer marketing has bifurcated into two distinct endorser types: key opinion leaders (KOLs), high-reach professional influencers, and key opinion consumers (KOCs), ordinary consumers whose product reviews derive persuasive power from authenticity rather than fame. Although both are now central to social commerce strategy, little is known about whether they persuade through the same psychological mechanism. Drawing on source credibility theory and the cognition–affect–behavior (CAB) framework, this study compares how trust, product attitude, and perceived endorsement effectiveness shape purchase intention across the two endorser types. Survey data from 163 social media shoppers in Ho Chi Minh City, Vietnam, who purchase via Facebook, Instagram, and TikTok were analyzed with partial least squares structural equation modeling (PLS-SEM). Trust strongly shaped product attitude for both endorser types. The downstream mechanisms, however, diverged sharply: for KOLs, neither trust nor product attitude translated into purchase intention—only perceived endorsement effectiveness did—whereas for KOCs, trust and product attitude significantly drove purchase intention while perceived effectiveness did not. The findings suggest that consumers process professional endorsements through a utilitarian performance lens but process peer endorsements through a relational trust lens, implying that KOL campaigns should demonstrate product performance while KOC campaigns should cultivate authenticity. The study contributes one of the first direct model-based comparisons of KOL and KOC persuasion mechanisms in an emerging Southeast Asian market.

Keywords: key opinion leaders, key opinion consumers, influencer marketing, trust, product attitude, purchase intention, social commerce, PLS-SEM.