With the rapid expansion of social media-based commerce, influencer-created product development and active follower involvement in the creation process have emerged as significant phenomena. This research investigates how social media influencers establish trust by transparently disclosing the product creation journey to their followers. Drawing on trust transfer theory, this study examines the mechanism through which trust developed during the creation process transitions into trust toward the final product. Additionally, utilizing the elaboration likelihood model, this research explores how the disclosure of co-creation activities influences consumers’ purchase intentions. Product-related factors are analyzed through the central route, while influencer-specific characteristics are examined through the peripheral route. The findings reveal that value co-creation in product development significantly enhances trust in the product creation process, and psychological distance to the influencer played a critical role in shaping trust toward the influencer. Notably, while trust in the product creation process and the product itself significantly affected purchase intention, trust in influencer did not exert a direct impact. These results provide both theoretical and practical insights into the underlying mechanisms of consumer decision-making within influencer-driven social commerce.