....... ....... I personally am a chain vaper.. I vape 12mg nic liquid and vape about 6ML a day. SO my DAILY nicotine consumption is somewhere around 72mg of Nicotine if you considered it was 100% absorbed which it isn't....
If you consider theres 1-3 MG of nicotine in a cigarette and I was a chain smoker at 3 packs a day.. I ingested almost 200MG of nicotine a day smoking cigarettes (Considering 100% absorption) along with the rest of the BAD stuff in cigarettes..
Actually we can't really calculate how much nicotine you are receiving because there is no agreement on this issue, since there are no proper studies, only informal DIY tests and the like.
Current opinion is that probably around 50% of the nicotine in e-liquid makes it into the vapor - but this cannot be stated as fact, since all sorts of 'ad hoc' tests produced a result from 10% to 95%, although the majority of them are in the 45% to 55% range. So a carto with a total of 18mg of
deliverable nicotine in it might deliver 9mg to the vapor, if our current assumptions are somewhere near the mark.
Tobacco cigarettes contain an average of 18mg of nicotine before combustion, and the smoke from one cigarette contains about 1mg of nicotine (conversion is not efficient, perhaps only 5% of the nicotine makes it into the smoke). This amount is falling and an average amount is probably about 0.8mg now.
E-liquid contains an average of 18mg nicotine per ml. A regular carto contains about 1ml (i.e. a 35mm x 9mm standard cartomizer), and some liquid cannot be utilised as it remains in the filler, so perhaps 80% can be used. As 80% of 18mg = 14.4mg, we probably get 14.4mg divided by 2 from a carto = 7.2mg. Conversion appears much more efficient than a cigarette, but even so we likely receive only 50% of the liquid nic in the vapor.
A 60-a-day smoker would probably be getting up to 60mg nicotine a day (though more likely, these days, about 48mg @0.8mg/cig).
[edit]
I had previously misread your post as reading 3ml per day (unless it was edited) therefore I've re-run the following calcs and adjusted the commentary to take account of this.
A 6ml-a-day x 12mg vaper is probably receiving about: 6 x [(12 x 80%) x 50%] = 6 x (9.6 / 2) = 6 x 4.8 = 28.8mg of nicotine.
So indeed the nicotine consumption does seem to have been reduced by a factor of 2, although the numbers are perhaps lower than they might appear to be at first.
This is commonly seen and always raises the interesting question of, "Why exactly are we just as satisfied even though nicotine consumption is clearly reduced, perhaps by as much as a factor of 2?". Nobody knows, because this sort of research is not being carried out.