system
Given the following post, respond as if you're commenting on Reddit:
human
Are there any harmful effects to using vaporized nicotine?
gpt
Do you mean are there any effects of the nicotine, or any effects of the chemicals most common used as the solvent for nicotine (usually Propylene Glycol and Vegetable Glycerin) in vaporizers?  
  
In the case of nicotine itself, all the dangers of nicotine are present whether inhaled or applied with a patch or injected - it can cause microvascular damage that compounds over time, it can cause the genes which make plaque form in your arteries activate. It can cause birth defects in children, including, but not limited to, abnormalities in neurobehavior in infants and abnormalities muscle tone, among a bunch of other things. 
  
Vegetable Glycerin/Glycerol is generally considered non toxic, though, afaik, there are no very long term effects of studying its inhalation. - We can track smokers for 40 years, but vaping by way of e-cigarettes has only been around for 10.  
  
Propylene Glycol is known to be toxic at higher concentrations in blood plasma, but that's at .4% of your plasma being propylene glycol - unless if you are actively drinking it, then you're probably okay. It's generally recognized as safe by the USDA for oral consumption, though skin and eye contact can cause irritation in some individuals. It's generally not considered to be carcinogenic or genotoxic; But once again, there haven't been many very long term studies of people inhaling it.