Consenting participants will be assigned to guideline-based care (GBC: incorporating national guidelines and more recent evidence from clinical trials of pharmacotherapy for smoking cessation) or metabolism-informed care (MIC: identical to GBC but selection of medication based on NMR result). All participants received counseling from a nurse level certified tobacco counseling. After consent, participants undergo a blood draw for NMR, complete a baseline questionnaire, and are randomized to GBC or MIC. At approximately 1, 3, and 6 months post-consent, participants will provide follow up information via telephone questionnaire regarding symptoms, confidence in quitting, use of medications, and smoking status. At the 6-month follow-up time point, if a participant self-reports abstinence from smoking, the participant will be asked to complete a survey in-person and provide a sample of end-expired carbon monoxide for biochemical validation. At the 6 month time point, GBC participants who continue to smoke will be offered an additional phone call from the nurse tobacco counselor in which the results of the baseline NMR test will be given, along with a second prescription for a smoking cessation medication based on the NMR results (i.e., single arm crossover design). Two weeks after this additional phone call, the patient will be contacted for a final survey regarding use of medication and smoking status.