I was using 10% 100-proof vodka to thin my juices, and I am certain that I did feel some low-grade effects. I do not drink much at all, as I am very sensitive to alcohol's effects in general (one beer is plenty for me), and my lifestyle does not allow much for intoxicants. I do intense martial arts, sometimes with swords, and I do chemical physics research, so I have to be very sharp both mentally and physically. For 6 weeks I was using vodka to thin, and during that time I was dizzy all the time, had little equilibrium, and my martial arts and research were strongly and negatively affected. I switched to distilled water to thin my VG juices, and all symptoms vanished. Placebo? Maybe, but...
Flame away, I do not care, but inhaled alcohol is absorbed and does go right to the brain. Whether or not it affects you significantly is another story, but it does have the potential to. There used to be a device called a brandy pipe, which was a glass pipe that you put something like cognac or brandy in, and then simply inhaled the vapor. Even a small amount will give a significant and very dulling buzz. Back in the day I had one and so did my friends, but we didn't like it after a while. It was more narcotic than fun, and too strong.
My advice is if you are sensitive to alcohol, or cannot have it or its effects even a little, distilled water works about as well. The only issue is less flavor, but upping the flavor content fixes that. The TH I am getting is every bit as good as with vodka, but then I'm not a huge TH fan anyway. I find the TH with my VG/DW juices to be almost the same as an analog, but slightly less drying than with vodka. And I'm certainly getting all the nic I need, and there is no problem with vapor production at all.
Anything absorbed by the lungs has a straight shot to the brain. This is why smoking works so well for getting a nic fix. This is a physiological fact. Whether it affects you, depending on your tolerance or general drinking habits of alcohol anyways, is another story, but the alcohol is not decomposed in the atty at all, it is only vaporized. Some is exhaled, of course, but trying to put meaningful numbers on this to say whether or not you could do it is not possible. It affected me, not to the point of being unable to drive (but who knows?), but enough that I was unable to keep up the intensity I maintain in my world, which with martial arts can become genuinely dangerous, and with doing calculus and programming can require extreme focus. And that's enough for me. I'm totally fine now with DW, and not suffering any loss of vaping enjoyment at all.
Everyone is different, and evidently many here have little to no ill effects from vaping alcohol. I'm not trying to tell people what to do at all. Nor am I trying to pass judgment, or saying that it is a bad thing. But my suspicions have been backed up by someone I know in neurophysiology, and my repeated experiments with and without alcohol had reproducible results time and time again. Please do not try to argue with me about what I felt...I got into a strangely heated discussion in another thread about this. Evidently some people get very upset if I say I eliminated alcohol in juice because it was affecting me. If it works for you, and you are not negatively affected, great, but if you do not want alcohol in your life at all, distilled water (about 20% in my VG-only juices) works really well and is quite enjoyable.