PROJECT ABSTRACT FDA?s comprehensive plan on tobacco and nicotine regulation focuses on two key actions: 1) reducing nicotine levels in combustible cigarettes to make them minimally or non-addictive and 2) allowing for new forms of nicotine delivery to provide adult smokers with nicotine with lower resulting health harms than cigarettes. The public health impact of FDA?s proposed nicotine reduction policy hinge on the extent to which tobacco users and non-users understand the harms of nicotine in relation to specific products (e.g., e-cigarettes, nicotine replacement therapy (NRT), reduced nicotine content (RNC) cigarettes) and how this influences decisions made by non-users to try a product and by users regarding cessation, product switching, or continued use. Population data, including recent work by our group, highlight widespread public misperceptions of the health risks of nicotine that could undermine the public health benefits of FDA?s comprehensive plan. As a result, the introduction of FDA policies that reduce nicotine in some tobacco products while leaving it unregulated in others may require more nuanced public education about nicotine. Findings from our pilot work support that a brief nicotine corrective messaging intervention?similar to the messages likely to be seen on warning labels or in public education media campaigns?can correct misperceptions of nicotine, NRT, e-cigarettes, and RNC cigarettes in an online convenience sample of U.S. adults. The proposed study extends our pilot work to examine the effect of multiple exposures to nicotine corrective messaging (NCM) intervention (compared to a delayed intervention control) on nicotine beliefs and intention/use of tobacco and nicotine products in two parallel and complementary samples. A population-based study will estimate the potential public health impact of NCM on nicotine beliefs and tobacco- related behavioral intentions in 715 adult tobacco users and non-users, including potential unintended effects. A lab-based study will estimate the independent effects of NCM and RNC cigarettes, as well as their interaction, on nicotine beliefs and observed tobacco use behavior in 160 adult smokers who are explicitly told whether they have a normal nicotine content or RNC cigarette (i.e., unblinded). This study aims to provide insight into the real world impact of NCM communication efforts on tobacco use behavior in the general population and in adult smokers affected by a reduced nicotine content standard in combustible cigarettes. This study will test a set of evidence-based messages on nicotine, providing information on content and themes that could be used in future public education on nicotine to maximize the public health benefit of FDA?s comprehensive plan.