It’s not the nicotine that’s the issue though, it’s the effects of absorption of PG and VG.
There was some concerns that water molecules could form within the lungs whilst vaping IIRC.
My wife uses them at the minute. I stopped 4 years ago & have stayed stopped.
I too was concerned about where the “vape juice” came from therefore bought pharmaceutical grade base ingredients and done my homework. It now costs between £0.10p – £0.16p a day to “vape” and the dosage can be altered to suit. The grand master plan is to drop a milligram a week over 24 weeks then quit. Probably.