The "head rush" effect from smoking a cigarette is NOT related to smoke, but rather is a direct effect of nicotine absorption. There are numerous double blind placebo-controlled laboratory studies that consistently find a dose-related nicotine head-rush effect from nicotine delivered via intravenous, nasal or oral delivery. Does nicotine do what we think it does? A m... [Nicotine Tob Res. 2005] - PubMed - NCBI
So following on from that, the common lack of a head rush effect from vaping, is most likely because most ecigs do not deliver nicotine at a speed or dose that compares to a cigarette or snuff. Having said that, we now have one published study showing that SOME experienced vapors, using fairly advanced ecigs, CAN obtain a boost in blood nicotine concentration of around 10 ng/ml within 5-10 minutes, which is in a similar ball-park to a cigarette, and enough to give a head rush from the first vape of the day, before acute tolerance to nicotine effects builds up throughout the day. Electronic cigarettes: effective nicotine d... [Nicotine Tob Res. 2013] - PubMed - NCBI
Good info. Thanks for replying.