The World Health Organisation says that there are “more than 4 000 chemicals in tobacco smoke, of which at least 250 are known to be harmful and more than 50 are known to cause cancer.” (You don’t really need the full list, do you?) What’s inside an e-cigarette? the ingredients vary between brands, but usually include nicotine, propylene glycol and/or glycerine (the bases used to contain the nicotine), and flavouring.

Here’s your e-cigarette exclusive.

• Nicotine is an addictive substance.
 While low doses act as a stimulant,
high doses can be toxic and even fatal. E-cigarette cartridges and liquids need to be kept out of reach
of children in particular. Nicotine is not safe for pregnant women.

• Propylene glycol and glycerine are humectants (they absorb water), which can create dryness in the mouth and throat. The long-term effects need to be evaluated through trials and studies, but humectant exposure or inhalation has been linked to respiratory irritation and asthma in children.

• Studies of e-cigarette vapour 
(if you’re going to be pedantic, 
it’s actually an aerosol, as it’s 
made up of fine liquid droplets) have found traces of several 
“harmful and potentially harmful” elements and compounds. Some of these, like formaldehyde, may be formed when glycerine is heated. Others may come from cross-contamination with the metal casing, or during production of the casing or cartridges. Detected levels of these substances appear to be low, but this is one of the many areas where more research is required.