Evaluation of Dependence and Nicotine Replacement Therapy-Supported Cessation Efforts Among Regular Electronic Cigarette Use

This study aims to improve understanding of how people who use electronic cigarettes (ECIGs or e-cigarettes) respond when they try to stop using them and whether nicotine replacement therapy (NRT) can make that process easier. NRT products, such as nicotine patches and lozenges, are approved medications that help reduce nicotine withdrawal symptoms by providing nicotine without the harmful chemicals found in tobacco smoke or e-cigarette aerosol. The study has two parts. During the first part, all participants will continue using their own e-cigarettes as they normally would for three days. This allows researchers to understand each participant's typical e-cigarette use before any changes are made. In the second part, participants will be randomly assigned to one of two groups. One group will receive nicotine replacement therapy, including nicotine patches and nicotine lozenges, to use for up to seven days. The first two days are intended to help participants adjust to the medications while they continue using their e-cigarettes. During the following five days, participants will be encouraged to stop using their e-cigarettes while continuing to use the nicotine replacement products. The other group will be asked to stop using all nicotine and tobacco products for five days without receiving nicotine replacement therapy. Throughout the study, researchers will regularly ask participants about their cravings, withdrawal symptoms, motivation to quit, and experiences using or not using e-cigarettes. Researchers will also measure how much participants use their e-cigarettes and assess exposure to nicotine and other chemicals. The information collected will help researchers better understand whether nicotine replacement therapy can support people who are trying to stop using e-cigarettes. It will also help identify the most accurate ways to measure e-cigarette use and abstinence in future research, which may improve the development and evaluation of treatments for e-cigarette dependence.

Inclusion Criteria: * Participants will be at least 21 years of age * Report 5+ days per week of using a nicotine-containing ECIG that is a non-refillable pod-style (e.g., JUUL, Vuse Alto) or modern disposable (e.g., Elf Bar, PuffBar) for the past 6+ months. * Report smoking either \100 lifetime cigarettes but no regular smoking (some days or everyday) in the past year. * Current ECIG use will be confirmed via a semi-quantitative urinary cotinine value \> 4 (NicAlert), and current non-smoking status will be confirmed via an expired air CO level \15 days in past month, or being unwilling or unable to abstain from THC/cannabis during study conditions. * Use of non-cigarette tobacco (e.g., cigars, smokeless, hookah) on more than 5 days in the past month * Uncontrolled medical or psychiatric conditions, positive toxicology for illicit substances (e.g., cocaine, opiates, amphetamine) except THC * Alcohol use \>20 days in past month * Breastfeeding or positive pregnancy test.