Gender Differences in Switching From Smoking Regular Cigarettes to E-Cigarettes

Inclusion Criteria: * Aged 21 years or older * Reports being a daily or non-daily smoker (any self-reported smoking in the past 30 days) * Have an address where he/she can receive mail * Able to follow verbal and written instructions in English and complete all aspects of the study as determined by PI * Willing to have urine biospecimen samples taken, either in-home and returning them by mail, or in-person at an approved collection site. * Willing to use tobacco-flavored study electronic cigarettes * Agrees to comply with all MD Anderson institutional policies related to COVID-19 screening prior to any in-person research visit. * The individual agrees to not engage in study procedures or interactions with study personnel while operating a vehicle. Exclusion Criteria: * Individuals who report depressive symptoms in the moderately severe or severe range on the PHQ-9 (scores of 15 or above) or who report current suicidal ideation on the PHQ-9 * Uncontrolled or unstable medical condition (e.g., uncontrolled hypertension, angina, diabetes). * Evidence of cognitive deficits or instability that would preclude reliable study participation. * Being pregnant, engaging in breast-feeding, or being of childbearing potential and engaging in sexual activity that could lead to pregnancy and is not protected by a medically acceptable, effective method of birth control while enrolled in the study, as determined by self-report. Medically acceptable contraceptives include: (1) approved hormon…