Influencer Authenticity in Marketing: A Systematic Literature Review and Future Research Agenda

As influencer marketing scales into a mainstream advertising channel, authenticity has become its defining currency, yet consumers and brands struggle to understand what makes a social media influencer (SMI) genuinely credible and why strategic authenticity backfires. Despite growing scholarly interest, research remains fragmented, leaving practitioners without a unified framework to guide their decisions. Through a systematic literature review (SLR) of 138 peer-reviewed articles (2011-2024), using topic modeling and thematic analysis, we identify the authenticity paradox, the inherent conflict that arises when SMIs attempt to commercialize their genuine self-presentation. This tension also explains why recent evidence reports no overall engagement benefit from perceived authenticity. Seven latent topics are synthesized into four integrated axes: (1) ontological tensions at the technological interface, (2) the commercial transparency and trust paradox, (3) ethical negotiation in identity construction, and (4) strategic consumer responses. Our findings reveal how consumers continuously navigate between SMIs' curated performances and perceived genuineness, with self-determination theory, attribution theory, and parasocial interaction theory dominating current explanations, predominantly within USA-based contexts. Beyond mapping the field, we specify three conceptual patterns, namely authenticity as attributed intent, transparency as coherence rather than concealment, and authenticity as a structurally constrained accomplishment. We then translate the gaps they expose into a structured research agenda, offering actionable insights for brands, managers, and platform designers on authenticity management, influencer selection, partnership governance, and performance evaluation.