Firstly, electronic cigarettes contain nicotine which is the highly addictive substance found in tobacco and are therefore not recommended to be used by non smokers.
However, nicotine by itself is not known to be as harmful or cancer causing as burning tobacco is.
The e-liquid contained in the cartridges itself is a combination of nicotine, propylene glycol and/or vegetable glycerin, and flavor. The propylene glycol and vegetable glycerin are the main atomizing agents that produce the vapor due to their high propensity to retain water.
Propylene glycol is an organic additive typically found in food coloring and cake mixes. It is considered to be safe by the Food and Drug Administration (FDA). However, the effects of direct inhalation repeatedly via eCigarettes is still undetermined, and more studies will need to be done, many of which are underway as we speak. Early indications are fairly positive, but not large enough in scope yet to make a definitive determination.
Propylene glycol and vegetable glycerin are already used and have been used for decades in tons of household products, medical nebulizers, medical inhalers, and many of the smoke machines you see in nightclubs and concerts. The safety effects of those products are well documented and regulated already and are known to pose very minimal risk for those uses. But again, repeated direct inhalation still needs more data.
The effects of nicotine are also extremely well documented and studied. Any decent medical researcher will tell you that nicotine, albeit the most addictive part of cigarettes, is not what is the most harmful part of it. The harmful part of traditional cigarettes is the combustion of the tobacco…it’s the burning aspect…just as inhaling smoke from a grill or campfire is also filled with many of the same carcinogens.
