In recent years, the rapid spread of social media on a global scale has significantly changed the dynamics of digital marketing, and in particular the critical role of influencers in product and service promotion. This study aims to examine the influence of variables such as attitudes towards influencers, influencers' physical and social attractiveness, their expertise, credibility, and the brand image of the products they promote on influencers' intentions to purchase products or services. The research envisages analyzing these relationships through a structural model. In the model, attitude towards influencers, physical and social attractiveness are defined as exogenous latent variables, while trust in influencers, their expertise and the brand image of the promoted brand are identified as mediating endogenous latent variables. The sample of the study consists of 306 users who follow at least one influencer on social media. Data were collected through online surveys. Partial Least Squares Structural Equation Modeling (PLS-SEM) was used to test the hypotheses and evaluate the fit of the model. The findings show that the fit of the proposed model is within acceptable limits and only two hypotheses are not supported. The strongest relationships are between attitude towards influencers and influencers' expertise, between the attractiveness of influencers and the image of the promoted brand, and between brand image and purchase intention.