Males and females do not differ in IQOS reward, reinforcement, or abstinence relief.

IQOS appears to similarly aid females and males in smoking reduction.

Males and females substitute IQOS for combustible cigarettes at a comparable rate.

More males versus females fully switch from cigarettes to IQOS, but not significantly.

Through secondary data analyses, we investigated sex differences in the effects of IQOS, a heated tobacco product, on combustible cigarette smoking.

Adults who smoke cigarettes (N = 118; 21–65 years old) completed a baseline ad-lib smoking period (days 1–5), two laboratory visits (days 6–7), and a 14-day period where they were instructed to switch from smoking cigarettes to using IQOS 3.0 (days 8–21). Models estimated the changes in cigarettes smoked per day (CPD) and the percentage of baseline CPD substituted by HeatSticks during the switch period. Bivariate statistics assessed sex differences in covariates and IQOS-associated effects (i.e., subjective reward, relative reinforcing value, craving relief, and withdrawal relief) for model inclusion.

Males and females significantly reduced their CPD to 29.8 % and 21.8 % of their baseline CPD by the end of the switch period, respectively. CPD slopes were significant for males (β =-0.46/day [CI95 % −0.97 to −0.04] p = 0.002) and females (β =-0.83/day [CI95 % −1.34 to −0.31] p < 0.001), although slopes did not significantly differ (p = 0.3). Males and females substituted HeatSticks at 83.2 % and 67.4 % of their baseline CPD across the switch period. The IQOS slopes were significant for males (β =1.136/day [CI95 % 0.59–2.14] p = 0.001) but not females (β =0.64/day [CI95 % −0.67–1.94] p = 0.34), although the slopes did not significantly differ (p = 0.36). There were no significant sex differences in IQOS-associated effects (all p values > 0.05).

Males and females do not appear to differ in IQOS-associated effects or the initial substitutability of IQOS for combustible cigarettes.

Cigarettes

Combustible

Heated tobacco products

IQOS

Sex differences

© 2025 The Authors. Published by Elsevier B.V.