Social media marketing and consumer purchase decisions: A preferred reporting items for systematic reviews and meta-analyses (PRISMA) based systematic review of marketing strategies, consumer trust, and brand loyalty

Abstract

Social media marketing has become a critical digital marketing strategy for influencing consumer purchase decisions; however, existing evidence remains fragmented regarding the relative effectiveness of different social media marketing strategies and the roles of consumer trust and loyalty. Previous reviews have largely focused on isolated dimensions, such as influencer marketing, customer engagement, or trust in social commerce, providing limited integrated evidence on the broader influence of social media marketing. This study systematically reviewed empirical evidence published between 2020 and 2025 to identify the most effective social media marketing strategies and examine how consumer trust and loyalty influence consumer purchase decisions. The review was guided by the Stimulus-Organism-Response (SOR) Theory and followed the PRISMA 2020 guidelines. A total of 19,948 records were identified from Scopus, Google Scholar, Emerald Insight, and SpringerLink, of which 32 empirical studies met the inclusion criteria after systematic screening, eligibility assessment, and methodological quality appraisal using the Mixed Methods Appraisal Tool (MMAT) (2018). Thematic synthesis identified two overarching themes. First, social media marketing activities, electronic word-of-mouth (eWOM), influencer marketing, consumer engagement and personalization, and brand image were the most effective strategies influencing consumer purchase decisions. Second, brand trust, brand loyalty, consumer trust, and information credibility emerged as the principal mechanisms linking social media marketing to purchasing behaviour, with brand trust representing the most consistent pathway. This review provides an updated synthesis of recent empirical evidence, extends existing literature by integrating multiple social media marketing strategies and trust-related mechanisms within a single review, and offers evidence-based guidance for researchers and practitioners seeking to enhance consumer purchase decisions through social media marketing. The study concludes that integrated, informative, interactive, credible, and trust-oriented social media marketing strategies can strengthen consumer purchase decisions, while organizations should tailor these strategies to their target audiences, products, and market contexts. Future research should employ longitudinal and mixed-method designs and examine emerging social media technologies and contextual factors to strengthen understanding of consumer behaviour.