The simulation heuristic of Kahnemann and Tversky (1982) suggests that the subjective ease by which a risky situation can be mentally construed, positively influences the person's perceived susceptibility to the presented threat. Assuming that a detailed outline of how a risky event can end up negatively increases the ease of imagination, we tested the hypothesis that scenario-based risk information enhances perceived susceptibility towards contracting a sexually transmitted infection (STI). In an experimental design, undergraduate students were exposed to one or two risk scenario messages or no scenario message (control). The results confirmed the hypothesis, but only when more than one risk scenario message was provided. This adds to the evidence that presenting scenario-based messages could be a feasible method to influence risk perceptions.