THRIVE Study: Understanding How Oral Nicotine Pouches Affect Public Health

This investigation expands on the parent study's Aims 1 and 2 by examining the effects of a feature that the investigators have identified varies across nicotine pouches (ONP): particle size. The investigators expect that particle size differences may translate to differences in user experience. The investigators wish to further explore this hypothesis among current ONP users. Data will be captured over the course of 3 clinic visits and across two week-long switching periods with daily diary surveys. This will inform interpretation of results from Aims 1 and 2, including how to translate those findings to commercially-available nicotine pouches.

Aim 1: Assess the effects of nicotine concentration, form, and isomer on the satisfaction and appeal of ONPs relative to cigarettes and ST. ONPs with high FBN and \>99% S-nicotine will have (H1a) increased satisfaction and appeal (e.g., faster nicotine delivery, greater liking). H1b: Associations of form and isomer with addiction potential and appeal will be strongest in the high nicotine concentration arm.

Aim 2: Evaluate the effects of nicotine concentration, form, and isomer on switching from cigarettes or ST to ONPs. Over 4 weeks, participants randomized to use ONPs with high FBN and \>99% S-nicotine (vs. other ONPs) will report higher prevalence of (H2a) partially switching to ONPs (use ONPs \>14 days but continued usual product use) and (H2b) complete switching to ONPs by week 4. H2c: Associations of form and isomer with switching outcomes will be strongest in the high nicotine concentration arm.

Study Procedures:

Participants will complete three in-person visits. Visits involve randomized, double-blinded use of either small-particle ONPs or a distribution of particle-size ONPs (one assigned product per visit).

Visit 1

* 12-hour abstinence requirement prior to visit. * Informed consent procedures. * Baseline questionnaires. * Exhaled carbon monoxide (CO) testing and pregnancy screening (if applicable). * IV-line placement followed by four timed blood draws to assess plasma nicotine levels. * 120-minute controlled ONP use session.

Post-use surveys assessing:

* Product appeal * Withdrawal symptoms and relief * Sensory scales * Behavioral intentions

One-Week Switching Period (at-home)

Following Visit 1, participants enter a 7-day ad libitum use period using their assigned ONPs.

During this phase, participants complete online daily diary surveys (1 per day) to capture product use and switching behavior.

Visit 2

* 12-hour abstinence prior to visit. * Exhaled CO testing and pregnancy screening (if applicable). * IV-line placement and four timed blood draws (plasma nicotine levels). * 120-minute controlled ONP use session. * Post-use surveys (same as Visit 1).

One-Week Switching Period (at-home)

Following Visit 2, participants enter a 7-day ad libitum use period using their assigned ONPs.

During this phase, participants complete online daily diary surveys (1 per day) to capture product use and switching behavior.

Visit 3

* Completion of survey measures only (no product administration or IV-lines). * Return of unused ONPs from the at-home switching period.

• Switching Behavior [Time frame: 2 weeks]
• Nicotine Delivery, Tmax [Time frame: 2 weeks]
• Nicotine Delivery, AUC [Time frame: 2 weeks]
• Craving Relief, QSU [Time frame: 2 weeks]
• Withdrawal, MNWS [Time frame: 2 weeks]
• Product Appeal, mCEQ [Time frame: 2 weeks]
• Intensity of Sensory Attributes, gLMS [Time frame: 2 weeks]