What do e-cigarette cartridges contain?

The solutions are often referred to as e-liquid or e-juice. Typically, they contain hundreds of flavors. For those desiring nicotine without smoke, the solution contains nicotine dissolved in propylene glycol and/or vegetable glycerin - both common food additives. Experts say propylene glycol has had no serious known side effects since the 1950s when it was included in nebulizers and asthma inhalers. In fact, the FDA (Food and Drug Administration), USA, includes this ingredient as one of its GRAS (Generally Recognized as Safe) substances. The solutions come in varying levels of nicotine concentrations, ranging from zero to extra-high (24-36 mg/ml). Some flavors, such as tobacco/menthol combinations, try to resemble traditional cigarettes. A number of them claim to mimic specific brands too. Further reading E-cigarettes were first introduced into the market in 2007 and have courted controversy ever since, with some studies suggesting they may cause harm to the lungs and others suggesting they are an effective smoking cessation aid. In July 2015 we published an article, Are electronic cigarettes safe? in which we discussed the evidence.