Impact of messages about scientific uncertainty on risk perceptions and intentions to use electronic vaping products

•The health effects of using electronic vaping products (EVPs) are unclear.•We used an online experiment to examine reactions to this scientific uncertainty.•Adults who viewed an uncertainty message (vs. control) rated vaping as less risky.•There were no effects of message on behavioral intentions to start or stop vaping.•Health communications should consider the impact of uncertainty on EVP perceptions.