Objectives According to the terror management health model, conscious thoughts of death motivate productive health behaviours when the targeted behaviour is perceived as an effective route for mitigating the threat and removing death-related thought from focal awareness. The present study thus examined whether messages manipulating the efficacy of a health behaviour moderate health outcomes when participants are presented with a fear appeal that makes death thought conscious. Design A 3 (fear appeal: cancer vs. appearance vs. neutral) × 2 (delay vs. no delay) × 2 (effective vs. non-effective) between-subjects ANOVA was conducted. Methods Beach patrons were randomly assigned to a cancer, appearance, or neutral-threat fear appeal followed by a delay or no delay. Subsequently, they read messages highlighting the effectiveness or ineffectiveness of sun protection behaviours and reported their intentions to engage in those behaviours. Results When fear appeals primed conscious thoughts of death, framing sun protection as ineffective decreased sun protection intentions relative to framing sun protection as effective. In contrast, fear appeals that did not consciously prime death, or appeals followed by a delay that allowed thoughts of death to fade from consciousness, did not interact with efficacy messages. Conclusions The findings revealed that messages impacting sun protection efficacy moderated sun protection intentions only when death was conscious. The findings have implications for understanding the conditions that render certain fear appeals, and accompanying messages of efficacy, more influential than others. Statement of contribution What is already known on this subject? Health communications that arouse fear motivate adaptive health behaviours to the extent that people perceive that the behaviour is capable of being performed (i.e., self-efficacy) and will be effective at preventing the undesired outcome (i.e., response efficacy). According to the terror management health model ( TMHM), health threats associated with mortality activate conscious thoughts of death. Moreover, the TMHM has found that when death thoughts are conscious, the belief that a health behaviour is effective predicts greater prevention intentions in an effort to remove the health threat, and conscious thoughts of death, from focal attention. What does this study add? Framing sun protection behaviours as effective increases sun protection behaviours among individuals exposed to a fear appeal that primes conscious thoughts of death (e.g., skin cancer from sun damage) relative to framing the behaviour as ineffective., Framing sun protection behaviours as effective after a fear appeal that does not prime death-related thoughts (e.g., appearance damage from sun damage) does not affect sun protection behaviours., Framing sun protection behaviours as effective or non-effective has no effect on sun protection intentions when death is no longer conscious. [ABSTRACT FROM AUTHOR]