RecruitingPhase 4Drug trialVarenicline and Accelerated Transcranial Magnetic Stimulation (TMS) for Quitting Nicotine Use (Pilot Study)The goal of this clinical trial is to learn if a combination of varenicline and enhanced accelerated Transcranial Magnetic Stimulation (aTMS) works to help adults quit using nicotine products. Researchers will compare varenicline + active aTMS with a single dose of D-Clycloserine to varenicline + sham (inactive) aTMS with a placebo pill to see the effect of enhanced aTMS on reaching abstinence. The main question it aims to answer is: Does receiving active enhanced aTMS + varenicline lead to higher abstinence rates and lower nicotine craving? Participants will be asked to: * Complete 2 brain MRI scans * Take varenicline every day for 12 weeks * Quit using nicotine products at the end of the second week of varenicline * Complete one day of up to 20 TMS treatments * Take a single dose of D-Cycloserine medication on the day of TMS treatment * Complete 12 brief, weekly follow-up visits * Complete a brief daily survey each day that they take the study drug