The purpose of this research study is to understand whether concurrent treatment for cigarettes and e-cigarettes in which an individual quits both products at the same time (QUIT-C) or sequential treatment in which an individual quits cigarettes first followed by e-cigarettes is more effective for quitting both products. The study will also compare the effect of treatment on health-related biomarkers. All participants will receive varenicline, a medication used to treat tobacco use dependence, counseling, and cessation resources (i.e., links to text-based support, self-change booklet). Varenicline helps to reduce cravings for tobacco use and decreases the pleasurable effects of cigarettes and other tobacco products.

Inclusion/exclusion criteria will be determined via initial online screening and then confirmed with tele-video/phone call final screening. Non-pregnancy verification will be ascertained via remote pregnancy test.

All participants will be asked to provide assessments (as described below) throughout the sampling process to assess cigarette smoking and e-cigarette use behavior, varenicline use, and use of cessation resources.

This is a 12 week, open-label study of varenicline.

Inclusion Criteria:

• English literate
• Report cigarette smoking, and e-cigarette use for at least the past 3 months
• Smoke 5 or more cigarettes per day
• Report e-cigarette use for at least 14 days in the past month
• Interested in quitting both products in the next month and willing to set a quit date.

Exclusion Criteria:

• Vulnerable Populations: Investigators will not be enrolling vulnerable populations, specifically pregnant women, children, prisoners, or institutionalized individuals
• Investigators also will not enroll participants incapable of providing their own consent. The rationale will be provided to the individual as well as his or her family members. Referrals for further evaluation, including urgent or emergent evaluation, will be made as needed and clinically warranted.
• Investigators will exclude anyone currently using any smoking cessation services and/or FDA pharmacotherapies.
• Verification of Non-Pregnancy: Females ages <55 will be given a commercially available pregnancy test to verify non-pregnancy. A female of child-bearing age that is currently pregnant or breastfeeding or report an unwillingness to use effective birth control (i.e., abstinence, IUD, implant, sterilization, pill, patch, ring, or barrier method such as condoms with spermicide) for the duration of the study will not be enrolled.
• Individuals using other tobacco or nicotine products besides cigarettes and e-cigarettes > once per week in the last 30 days will be excluded.
• Investigators will exclude individuals with medical contraindications for varenicline use (i.e., severe renal impairment and unstable cardiac history)
• Medical Conditions: Investigators will not enroll anyone with a current, serious uncontrolled medical/psychiatric condition (e.g., a condition that required a hospitalization or intensive outpatient treatment in the past year) based on review by Study Physician that would increase risk of severe adverse events and/or interfere with study participation.