Recent research conducted at Oregon Health and Science University and published in the Journal of Chemical Research in Toxicology suggests that different brands of cigarettes are differently addictive based on different amounts of free-base nicotine. Quite intuitively, the researchers think that more freebase = more addictive. That would be why cigarettes have alkaline additives like ammonia and urea!
Camels rank quite low, at 2.7% free base. But regular Camel smokers have trouble quitting just like anybody else. Marlboros are at 9.6%, though obviously that doesn’t mean that they are anything like “four times as addictive” as Camels – the nicotine which isn’t in free-base form is still addictive. American Spirits are pretty hard-core at 36% free base. Take that, hippies!
(Addendum 7/30/03 – I’m not saying American Spirits have additives – certain kinds of tobaccy are just more alkaline and American Spirits must use those, or else it’s some other factor in the preparation…)