For millions of people, social media influencers now shape everyday decisions about what to buy, what to trust, and which brands feel authentic. From fashion and fitness to technology and travel, influencer posts appear woven into daily online life, raising a simple question for businesses and consumers alike: what actually makes an influencer persuasive. The findings were published in the Journal of Business Research.
A large new academic review suggests that common assumptions about influencer success may be misplaced. The study analysed more than 100 separate research studies to identify which factors consistently drive engagement and purchasing decisions when people encounter influencer marketing online .
One of the clearest findings challenges the idea that bigger is always better. While influencers with large followings may reach more people, higher follower numbers were not reliably linked to stronger engagement. In fact, as audiences grow, the sense of personal connection that encourages likes, comments, and shares can weaken.
Instead, engagement appears to be driven by how relatable and relevant influencers feel to their audiences. Similarity between influencers and followers, whether in values, lifestyle, or interests, showed a strong and consistent link with higher engagement. Content that feels original, informative, and clearly expressed also played an important role.
The study found that content quality matters more than volume. Posting frequently did not automatically increase engagement or buying interest. Well produced posts that offer useful information or clear opinions were more effective than repetitive or low effort updates.
When it came to encouraging purchases, different factors came into play. Physical attractiveness, expertise in a subject, and overall credibility were linked to higher purchase intention. Informative content again stood out, suggesting that people are more likely to buy when influencers explain products clearly rather than relying on emotional appeal alone.
Brand and influencer fit also mattered. Audiences were more likely to consider buying a product when there was a clear connection between the influencer and the brand being promoted. This supports the idea that credibility depends on consistency rather than popularity.
The review also examined the impact of sponsorship disclosures. While openly declaring paid partnerships did not significantly reduce engagement, it was linked to lower purchase intention. This suggests that transparency changes how audiences interpret persuasive messages, even if it does not stop them interacting with content.
Taken together, the findings point to a more nuanced picture of influencer marketing. Success appears less about chasing celebrity level reach and more about matching the right voice, content style, and audience. For brands, this means smaller influencers with focused communities may sometimes be more effective than global names.
For users, the research highlights why certain influencer posts feel more convincing than others. Influence is not just about numbers on a profile page, but about perceived relevance, clarity, and trust built over time.