- Subjects must be 18-65 years old, have smoked an average of at least 10 cigarettes per day for three cumulative or continuous years of a brand that delivers (by Federal Trade Commission rated yields) at least 0.5 mg nicotine, have an expired air carbon monoxide reading of at least 10 ppm, and express a desire to quit smoking. Additionally, subjects must express a willingness to switch to denicotinized cigarettes. A more dependent smoker is defined as someone with an FTND score of seven or greater. A less dependent smoker is defined as someone with an FTND score of less than seven.