Purpose The purpose of this paper is to evaluate the differential effects of help-seeking and product-claim direct-to-consumer advertising (DTCA) on consumers' attitude toward the ad, intention to seek information and intention to see a doctor. This paper also seeks to examine the underlying mechanism of these effects and the moderating role of advertising literacy. Design/methodology/approach An online experiment was conducted with 130 adults who experienced narcolepsy symptoms and experimental stimuli promoting a fictitious drug for narcolepsy. Findings Help-seeking DTCA generated lower persuasion knowledge activation than product-claim DTCA, resulting in lower skepticism, more favorable attitude toward the ad and higher behavioral intentions. The effects of ad type were stronger among consumers with higher advertising literacy. Originality/value This is the first study that provides a thorough examination of the underlying mechanism of the differential effects of help-seeking vs product-claim DTCA as well as the roles of consumers' advertising literacy on ad outcomes.