Electronic word of mouth on Instagram and purchase confidence among first time buyers: A systematic literature review

Abstract

Abstract

Social media platforms have fundamentally altered how consumers gather product information and form purchase decisions, with Instagram emerging as a particularly influential environment for electronic word of mouth (eWOM). Despite a growing body of research on eWOM and purchase intention, comparatively little attention has been directed toward purchase confidence, defined as the degree of certainty a consumer experiences when making an unfamiliar purchase, particularly among those buying a product for the first time. This study addresses that gap through a systematic literature review conducted using the PRISMA framework, drawing on 31 peer reviewed studies retrieved from Scopus and Google Scholar and published between 2016 and 2025. Thematic analysis of the selected studies identified five recurring themes: eWOM credibility and consumer trust, influencer marketing and Instagram content strategies, social engagement and social proof, eWOM and purchase intention, and purchase confidence among first time buyers. The findings indicate that credible online reviews, authentic influencer endorsements, and visible engagement signals such as likes and comments collectively reduce purchase uncertainty and build consumer confidence, most notably among individuals with limited prior product experience. Word cloud analysis of study abstracts further confirmed that trust, engagement, and social influence are the dominant constructs shaping this field. The study contributes to digital marketing and consumer behavior literature by synthesizing fragmented evidence across multiple dimensions of Instagram based eWOM and by repositioning purchase confidence as a theoretically distinct and practically meaningful outcome that extends beyond purchase intention. The findings offer actionable guidance for brands, marketers, and policymakers seeking to design credible and confidence building social media communication strategies.