About one year before I quit smoking, I changed from buying my cigarettes, to purchasing whole leaf organic tobacco. Yes, I had to shred it, get the humidity right, and roll it in a little roller. There was a huge difference. I would have to snag a real smoke (usually by trading one of mine for someone else's) on occasion. There were times when I couldn't get enough rolled when I was busy doing stuff. I managed to stick to my smokes for about 3 months straight, then I bought a pack of Camels.
I took a drag. What the hell? It was like smoking a cigarette for the first time in my life. I got real dizzy, light headed, etc. I went back to my organic roll your owns until right about a year, then I got myself a vape.
So there is definitely something else in there, and if you are wondering, it's in those American Spirits also. In fact, those other inidan brands, Signal, all of them. Although those brands have less than Camels. (Opinion/Observation) Testing is difficult, you'd have to smoke organic for a month, then try a cig of another brand.
BTW: Whole leaf organic hand rolled smokes with a 20mm filter costs about 80 cents a pack. There are no sin taxes on whole leaf, it's an agricultural product. Was it any healthier? I don't really think so, aside from not having that unknown stuff in them.