Nicotine Metabolism and Low Nicotine Cigarettes

Inclusion Criteria: 1. adults age 21-65. 2. smoking at least 10 cigarettes per day. 3. smoking daily for the last 5 years. 4. Provide a baseline breath CO reading equal to or greater than 10 parts per million. 5. smoke predominantly non-menthol filtered cigarettes (research cigarettes are only non-menthol). 6. not currently using any other nicotine containing products such as cigars, smokeless tobacco, nicotine replacement therapies (patch or gum). 7. are fluent in English and are capable of providing written informed consent, which includes compliance with the requirements and restrictions listed in the combined consent and HIPAA form. Participants who meet the inclusion/exclusion criteria and attend an Intake Visit for medical screening will be asked to provide a blood sample to determine NMR. Only those individuals who are characterized as slow or rapid, based on NMRs ≤ .26, or ≥ .42, will be eligible. Exclusion Criteria: 1. use of any nicotine containing products other than cigarettes 2. current or impending enrollment in smoking cessation program 3. history in the last year or current treatment of substance abuse (other than nicotine dependence) 4. positive drug screen for cocaine, methamphetamines or opiates for urine drug screen at intake session 5. alcohol use greater than 25 standard drinks per week 6. current or planned pregnancy or lactating 7. history or current diagnosis of psychosis, bipolar disorder, mania, or schizophrenia 8. current major depression (history of major depression but in remission for a minimum 6 months is eligible). 9. serious or unstable disease within past year (e.g. cancer other than melanoma, heart disease) 10. history or current diagnosis of COPD 11. history of stroke or heart attack 12. age less than 21 years- We wish to recruit smokers with well established smoking patterns and will restrict recruitment to those over 21 13. age more than 65 years - smoking is often associated with cardiovascular and pulmonary obstructive diseases that manifest later in life. As smokers develop these problems, smoking behavior and biomarkers of harm may be affected therefore we will restrict enrollment to those under age 65 14. provide baseline CO reading less than 10 at initial session 15. current use (or use within past 14 days) of any medication that affects the biotransformation of nicotine, such as anticonvulsant drugs, rifampin, and disulfiram; or any psychoactive medications which can affect smoking behaviors 16. any conditions viewed by the PI or study physician as creating a potential increased risk to a participant due to their participation will be reasons for exclusion 17. at the discretion of the PI, any participants viewed as non-compliant will be excluded from further participation 18. Smoke cigarettes with a filter size other than standard or slim sized as the topography mouthpieces are sized for standard filters and have an adapter for slim cigarettes only.