In social media marketing, influencer-generated content (IGC) and user-generated content (UGC) are considered invaluable for brands and digital marketers to engage with consumers and shape their perceptions. However, the effectiveness of these strategies can vary significantly depending on the type of content source (influencer vs. user) and whether the audience clearly recognizes the influencer. This study investigates the impact of source type and source recognition (recognized vs. unrecognized influencer) on consumer engagement, credibility perceptions, and brand attitudes across three distinct brands: one from the non-luxury sector, a female-oriented luxury brand, and a male-oriented luxury brand. This empirical study employs a between-subjects experimental design in which participants are randomly assigned to be exposed to a social media post from an influencer or a regular user. Participants who viewed the influencer post were further categorized based on whether they recognized the influencer. Our findings reveal that, particularly in the case of luxury brands, influencer recognition determines consumer engagement and perceptions. The results provide actionable insights into using UGC and IGC in an effective manner.