Nicotine by itself is the same as caffeine.

[Chlamydia]

So many people believe the stigma that nicotine is the SOLE addictive chemical in cigarettes, and now e-cigarettes. That's a complete and utter LIE.

Yes, nicotine is an addictive chemical, but only mildly addictive. It acts the exact same as caffeine does, giving an energy boost or "buzz" as well as thinning out the veins. Is it completely harmless? No, but the fact some states and cities are outlawing e-cigs due to them being as harmful as cigarettes is stupid and a childish mistake. They're as harmful as coffee, but you don't see them closing down or banning coffee shops, do you?

http://ehealthforum.com/health/nicotine-myth-busted-nicotine-does-not-cause-addiction-t341366.html

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC19495/

http://www.statepress.com/archive/node/7194

My buddy did the research and sent me the links, I didn't understand all of the terminology in the second link, but still, it's kind of shocking how this isn't publicly known or addressed.