This study investigates the influence of fitness influencers on consumer trust and purchase intention within the activewear industry. With the increasing importance of social media as a commercial channel, particularly platforms like Instagram and TikTok, influencer marketing has emerged as a powerful strategy. Using a structured questionnaire, data were collected from 531 Greek consumers to test the relationships between influencer credibility, brand trust, and purchase intention. The results confirm all three hypotheses: influencer credibility significantly impacts trust and purchase intention, while trust also mediates purchasing behavior. These findings provide actionable insights for marketers and suggest avenues for further research on the evolving dynamics of digital influence.