That is generally true; the nicotine in e-liquid is commonly extracted from tobacco. But at the point it is mixed into an e-liquid, assuming we're talking about a reputable organization, it is a completely pure nicotine solution. The only thing it shares with the tobacco it came from is the nicotine itself.
Ah, didn't realize this. I used to work at a coffee roaster and at the time was told the caffeine removed from decaf beans via the swiss water method was then sold to soda companies.
