Enigma -
Welcome to the forum! I feel your pain completely about people who have quit smoking on their own, and are therefore convinced that theirs is THE way to go. Many of our species enjoy feeling superior, to the point of causing harm to others of their species. It's sad, really, but those people need our forgiveness, along with everyone else who does things we don't appreciate.
I ran into another one of those types a couple of weeks ago. Some guy in his hospital scrubs with "St. Francis Hospital Cardiology Dept." embroidered on them. I asked him if he would rather see his patients smoking cigarettes, or vaping. He "colored outside the lines" and said "neither". He had quit smoking, so everyone else should just do the same. He said that nictotine all by itself was still very harmful, and told me to look up "nicotinic acid" and "nitric oxide". When I got home, I did. Nictotinic acid is a synonym for niacin - Vitamin B3 - often taken as a dietery supplement to reduce "bad" cholesterol and raise "good" cholesterol. And nitric oxide is formed by the acetylaldehyde in tobacco smoke, not by nicotine. In my view, that makes this person dangerous to society.
In his defense, he did cause me to look further than I had before into the effects of nicotine (all by itself) on the human body, and I did find something that, if correct, is disheartening. It has little or nothing to do with what he said, but it just might be the case that nicotine does damage the linings of large- and medium-sized arteries by accelerating plaque formation:
"Recently, a study conducted at Brown University in Providence, RI, uncovers how nicotine contributes to cardiovascular disease.
According to the study, nicotine determines the endothelium, cells lining blood vessels, to remodel. Blood vessels consist of three layers: adventitia, media, containing smooth muscle cells, and intima, consisting of endothelial cells. Nicotine promotes the invasion of vascular smooth muscle cells (VSMCs) from the media to the intima. In addition, nicotine causes invading cells to remodel. More specifically, the actin cytoskeleton forms podosomes, which regulate metalloproteinase (MMP) release for the extracellular matrix (ECM) degradation. Consequently, this fact leads to vessel degradation and, eventually, to atherosclerosis. The results of this study will be presented at the 56th Annual Meeting of the Biophysical Society (BPS), held in February. 25-29 in San Diego, California".
Read more:
Research Involves Nicotine In The Pathogenesis Of Atherosclerosis
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HOWEVER: I think it remains indisputable - even if this research finding is confirmed - that vaping is vastly less harmful than smoking cigarettes, for obvious reasons. If nicotine itself actually does have this effect on blood vessels, then for me, [nicotinized] vaping will become more of an intermediate step away from smoking, with the goal of eventually getting off of vaping entirely, or at the least, reducing the nicotine level as close to zero as possible. After all, I spent my first six months of vaping at zero nicotine. Maybe I'll just have to find another source for increased dopamine levels in the brain, in place of nicotine.
Lastly - I too had open-heart surgery, and I too went back to smoking afterward, until finally discovering vaping. And I too was incredibly confused by all of the terminology, hardware choices, and the whole bit. Now there is an incredibly simple pathway to a very good vape:
Two or three Joyetech eGo-C Twists; I like the 650mah size
Two chargers in case one craps out
Two or three Vivi Nova tank/atomizers
Juice
That's it. That's what I'm using right now, after buying and researching ALL kinds of stuff for over a year.
If you email me, you or your BF can call me and I'll mentor you for free. He's gotta get off of the ciggies, which are now IMO unnecessary, since vaping is more enjoyable with the right hardware and the right juice.
Cheers.