To date, clinical trials have shown that, compared to the standard dose of transdermal nicotine (21mg), higher doses (42mg) have no significant effect on quit rates. However, no trial of high dose transdermal nicotine considered inter-individual variability in the rate of nicotine metabolism. Thus, as a preliminary step toward conducting a fully-powered, randomized clinical trial to assess standard vs. high dose transdermal nicotine for slow vs. fast metabolizers of nicotine, we propose to evaluate, for the first time, the efficacy of high-dose transdermal nicotine (vs. standard dose) among fast metabolizers of nicotine (i.e., upper quartile of the 3-HC/cotinine ratio distribution).