How the literature is organised
The first generation followed brands onto Facebook. Michaelidou, Siamagka and Christodoulides (2011) examined usage, barriers and measurement among small and medium-sized business-to-business firms. Kim and Ko (2012) showed that the social media marketing activities of luxury fashion brands improved customer equity, and Godey et al. (2016) extended this to brand equity and consumer behaviour across countries. De Vries, Gensler and Leeflang (2012) analysed which characteristics of brand posts attract likes and comments, and Ashley and Tuten (2015) catalogued creative strategies in branded social content.
The second generation is about people, not brands. Freberg et al. (2011) asked who social media influencers are, and Khamis, Ang and Welling (2017) read the rise of the influencer as self-branding under neoliberal individualism — a critical account worth reading against the marketing papers. Lou and Yuan (2019), the most-cited work here, built the model that most later studies adapt: their survey of social media users found the informative value of influencer content, and the influencer's trustworthiness, attractiveness and similarity to followers, positively affecting trust in branded posts, which in turn affected brand awareness and purchase intention. Jin, Muqaddam and Ryu (2019) ran a two-group experiment with 104 participants and found Instagram celebrities rated more trustworthy than traditional ones, with social presence mediating the effect — and envy along for the ride.
Main debates
Authenticity under commercial pressure is the recurring tension: Audrezet et al. (2020) on how influencers manage it, Kim and Kim (2021) on the conditions under which trust holds and fails. Ye et al. (2021) name the mechanism plainly, describing influencer marketing as effective partly because it is often not perceived by consumers as advertising — which is where the disclosure and regulation question starts.
Methodologically, watch what is being measured. Pan et al. (2025) separate non-transactional outcomes (attitude, engagement, purchase intention) from transactional ones (purchase behaviour and sales), and find different antecedents dominate each: follower social identity for attitude and engagement, post informational and hedonic value for purchase intention, influencer communication for actual purchase behaviour. A study that measures intention has not measured sales. On the public health side, Powell and Pring (2024) are blunt about quality: most of the published studies they found were of poor methodological quality with poor generalisability and statistical weaknesses.
Where recent work is heading
Dwivedi et al. (2021) set out research propositions for digital and social media marketing as a whole. Li, Larimo and Leonidou (2021) define social media marketing strategy and sort it into four types by maturity — social commerce, social content, social monitoring and social CRM — which is a ready-made framework for a case study. Leung, Gu and Palmatier (2022) conceptualise online influencer marketing, and Belanche et al. (2021), with 372 followers of a fashion influencer, show that the congruence that matters runs three ways, between influencer, product and consumer. Applied studies cover specific decisions: Pop et al. (2022) trace trust in influencers through each stage of the travel decision journey.
Public health researchers have begun reviewing the same phenomenon from the other side, which links this topic to the mental health literature. Powell and Pring (2024) found twelve interventional studies across children's dietary behaviour, body image, influenza and COVID-19, and social comparison, and report consistently negative effects on body image alongside some positive results for hygiene campaigns. Engel, Gell and Heiss (2024) scoped 51 articles published between 2012 and 2022 and found inconsistent definitions of what an influencer even is, most attention on appearance, nutrition and substance use, and little on mental or sexual health.
Search strings to copy
Written for databases that accept Boolean operators (Scopus, Web of Science, ERIC, PubMed, EBSCO). Quotation marks keep a phrase together, an asterisk stands in for the end of a word, and OR groups go in brackets. British and American spellings are written out with OR rather than covered by a single-character wildcard, because those wildcards differ between databases: PubMed’s help page documents the asterisk only, and asks for at least four characters before it. Limit the search to title and abstract first; widen it only if you get too little. Our guide to starting a literature review covers how to record what you searched.
Influencer marketing and purchase intention
("influencer marketing" OR "social media influencer*" OR "digital influencer*") AND ("purchase intention" OR trust OR credibility OR "parasocial")Brand activity on social media
("social media marketing") AND ("brand equity" OR "brand loyalty" OR engagement OR "customer equity")Disclosure and authenticity
("influencer*" OR "sponsored content") AND (disclosure OR authenticity OR "advertising recognition")How to cite these papers
Every paper above has a DOI, a part of the reference that is easy to leave out. Here is one of them, “Influencer Marketing: How Message Value and Credibility Affect Consumer Trust of Branded Content on Social Media” (2019), in the two styles students ask about most:
APA 7th edition
Lou, C., & Yuan, S. (2019). Influencer marketing: How message value and credibility affect consumer trust of branded content on social media. Journal of Interactive Advertising, 19(1), 58–73. https://doi.org/10.1080/15252019.2018.1533501
MLA 9th edition
Lou, Chen, and Shupei Yuan. “Influencer Marketing: How Message Value and Credibility Affect Consumer Trust of Branded Content on Social Media.” Journal of Interactive Advertising, vol. 19, no. 1, 2019, pp. 58–73, https://doi.org/10.1080/15252019.2018.1533501.
Check the details against the article itself before you submit: databases, including the one behind this page, sometimes carry the online-first year rather than the volume year. Full rules and more examples are in our guides to APA, MLA, Chicago, Harvard, Vancouver and ABNT, with the rest in the citation guides. You can also format a reference from its DOI with our free citation tools.
Frequently asked questions
What theories are used in influencer marketing research?
Source credibility and persuasion knowledge run through most of it: Lou and Yuan (2019) build their model on advertising value and source credibility, and Pan et al. (2025) organise their meta-analysis around the persuasion knowledge model with source credibility as a mediator. Congruity, balance and cognitive dissonance theories appear in the fit literature (Belanche et al., 2021). Vrontis et al. (2021) analysed 68 articles from 29 ranked journals and built an integrative framework of antecedents, mediators, moderators and contextual factors, which is the quickest way to see which theory fits your question.
Do influencers actually increase sales?
Leung, Gu and Li (2022), in the Journal of Marketing, found influencer originality, follower size and sponsor salience raising effectiveness, posts announcing new product launches lowering it, and influencer activity, follower-brand fit and post positivity all exerting inverted-U effects — so more is not better on any of those three. Note that most studies measure purchase intention in a survey rather than sales: Pan et al. (2025), synthesising 1,531 effect sizes from 251 papers, keep the two apart and find different drivers for each. Ao et al. (2023) pool 176 effect sizes from 62 studies and 22,554 people, and report entertainment value most strongly associated with engagement and credibility with purchase intention.
Should I search for social media marketing or influencer marketing?
They are overlapping literatures. Social media marketing covers a firm's own content, community management and paid social. Influencer marketing covers third parties paid or encouraged to promote. This page combines them because students search for both, but a thesis should choose one.
How this page was made
The lists come from OpenAlex, an open index of scholarly works whose data are published under a CC0 licence, queried on September 21, 2026 for works whose title matches ("social media marketing" OR "influencer marketing" OR "social media influencers"). Only works with a DOI are listed. Each one was checked against the publisher’s own record at Crossref or DataCite (title, year, first author, journal, volume and pages), and in three cases, where the publisher deposited no byline, against PubMed; anything OpenAlex or Crossref flags as retracted was left out, and an editor took out results that matched the words but not the subject. Citation counts are OpenAlex’s on that date and are usually lower than Google Scholar’s, which counts more kinds of document. Ranking by citations tells you what a field has relied on, not what is correct; several heavily cited papers on any topic are cited because later work disputes them. Books without a DOI are missing, which matters in fields where the founding text is a book.
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