The E-liquid nicotine or the “E-Juice” contained in the cartridge is a solution of propylene glycol and/or vegetable glycerin, distilled water, artificial flavoring and nicotine.
Propylene glycol and vegetable glycerin are flavoring carriers in food products, food coloring and commonly used as an additive in medications. These ingredients hold the nicotine and flavor in suspension.11 Exposure to propylene glycol can cause eye and respiratory irritation; prolonged or repeated inhalation in industrial settings may affect the central nervous system, behavior, and the spleen.45-46 When heated and vaporized, propylene glycol can form propylene oxide, a carcinogen47 and glycerol forms acrolein, which can cause upper respiratory tract irritation.48,49
There are many different options of artificial flavors that are available in the liquid nicotine. E-juice liquid is manufactured in tobacco, chocolate, fruit and candy flavors giving the user a wide array of flavors to choose from. Similar to cigarettes, sales and promotion of flavored e-cigarettes attract youth and new users to these products and encourage novices and youth to start using e-cigarettes and tobacco. In addition, use of flavorings contributes to dual use of cigarettes and other products among those who are trying to quit smoking cigarettes.50
Most e-liquids come in several strengths: high, medium, low, and zero. But different companies may have different standards for strength. E-liquids commonly come in 24 mg, 18 mg, 12 mg, 6 mg or no nicotine.11 However, since e-cigarettes and e-liquids are currently unregulated, the actual nicotine content and concentration in e-liquids often is different from what is stated on the labels.52-54