Nicotine is a vasoconstrictor. It substantially increases the risk of Deep Vein Thrombosis, especially when combined with another chemical that produces clotting enzymes, such as estrogen. Speaking of estrogen, nicotine also antagonizes the estrogen receptor, which is pretty bad if you're a woman. Ever notice how women who have been smoking for a long time look pretty bad? It's not your imagination, it's because nicotine shuts down their bodies' ability to use estrogen (and estrogen is what causes smooth skin, curves, etc.).
Also, go look up "Green Tobacco Sickness" [0]. Too much nicotine can have all kinds of adverse effects, and since it can be absorbed by the skin, people who handle wet tobacco plants get all kinds of health problems. Oh, and too much nicotine can stop your heart. I've seen people seriously suggest it as a suicide method.
As for it being a vasoconstrictor, so is caffeine and any number of other stimulants, that itself in not inherently bad, it's simply an effect.
"Nicotine is bad for you."
"What about water??"
I don't know if it's intentional, but thanks for making my morning better. :)
Nicotine alone is not harmful, it's addictive, but not harmful, it's not what causes cancer from smoking.
All apparent evidence is that vaping appears vastly healthier than smoking and there's no reason yet to believe vapor is harmful to the lungs; you breath water vapor all day every day. Calling something "foreign chemicals" might sound scary, but is not a plausible reason to call something definitely unhealthy. The word definitely is very bold, and not remotely justified.
> People run around vaping like there are zero consequences
No, they run around like it's vastly safer than smoking, which it clearly is. There's zero evidence anything to do with vaping has the cancer causing effects of smoke and burnt carcinogens.