Take a cigarette, remove all the chemicals and carcinogens that get burnt and inhaled, leaving only nicotine, a stimulant much like caffeine, which has been shown to help with some maladies like Alzheimers. Add propylene glycol, used as an anti-bacterial inhalant in hospitals, and some vegetable glycerine. Pretty benign compared to a cigarette.
Not only is vaping less risky than smoking, but in my case, it has allowed my blood oxygen absorption to return from dangerously low levels to that of a non-smoker in a matter of three months. When I get a cold, it lasts for a couple days, much like during my college days. As a smoker, colds routinely turned into bronchitis and an inflamed lung, taking weeks and steroid treatments to overcome.
You don't even need to inhale the vapor, just puff it like a cigar, to get the nicotine. I think it is radically healthier.