Effect of flavored on!® nicotine pouch products on smoking behaviors: A sequential, multiple assignment, randomized controlled trial.

Abstract

To evaluate whether flavored versus unflavored nicotine pouch (NP) access affects cigarette reduction and smoke exposure among adults who smoke daily, and whether delayed flavor introduction affects these outcomes. Adults who smoked ≥ 5 cigarettes/day (CPD) with interest in replacing cigarettes with NPs were enrolled in a remote, six-week, sequential multiple assignment randomized trial (n = 402 randomized; n = 400 analyzed). Participants were randomized to immediate access to seven NP flavors (Flavor), unflavored-only access for six weeks (Original), or unflavored-only for three weeks followed by flavor access (Delayed Flavor). Primary outcomes were ≥ 50% reduction in weekly mean expired-air carbon monoxide (CO) from baseline and mean CO at Week 6. Secondary outcomes included ≥ 50% CPD reduction, mean CPD, CO-verified 7-day abstinence, and incident smoke-free days. At Week 6, Flavor and Original did not differ in ≥ 50% CO reduction (14.3% vs 14.2%; IRR=1.0, 95% CI=0.6-1.8) or mean CO (18.3 vs 16.5 ppm; β=1.9, 95% CI=-1.3-5.0). CPD decreased across groups by Week 6, with no differences between Flavor and Original in ≥ 50% CPD reduction (50.3% vs 51.6%; IRR=1.0, 95% CI=0.8-1.2) or CO-verified abstinence (9.3% vs 8.9%; IRR=1.0, 95% CI=0.5-2.2). Flavor increased smoke-free days early, with attenuation over time. Among Week 3 non-responders, delayed flavor access increased ≥ 50% CPD reduction at Week 6 (33.3% vs 18.6%; IRR=1.8, 95% CI=1.0-3.2). NP access supported cigarette reduction regardless of flavor availability, but flavors may accelerate smoke-free days and improve response among individuals who do not reduce cigarette consumption with unflavored products alone.