Vaping grew quickly. According to figures reported by the BBC, the number of adult vapers worldwide went from about 7 million in 2011 to 35 million in 2016, and was forecast to reach nearly 55 million by 2021. Vape shops appeared on high streets and online in their hundreds, and the smell drifting down the pavement became as likely to be cotton candy as tobacco smoke.
With that many people using e-liquid, it is fair to ask what goes into the bottle. This guide walks through the ingredients you will meet most often.
How e-liquid is used
An e-cigarette has two basic parts: a canister that stores the liquid and a small heating element. Heat turns the e-juice into an aerosol, and that aerosol is what you inhale.
Recipes differ from one brand to the next, but most manufacturers build on the same short list of components.
The base liquids
Vegetable glycerin (VG)
VG works as a thickener, a sweetener and a preservative. It is produced from vegetable oils, typically soybean, coconut or palm oil, and it is also a familiar food ingredient that turns up in jams, canned goods, cream, fondant, processed fruit and energy bars.
Propylene glycol (PG)
PG is an alcohol with no color, smell or taste. Some e-liquids use it alongside VG and some use it in place of VG. It carries flavor very well, though it makes less vapor, and because it acts as a preservative it helps a bottle keep for longer.
A number of people are sensitive or allergic to PG. If you are one of them, look for e-liquid made with VG.
Water
Water is another ingredient that commonly appears in vape liquid.
Flavoring
Flavors run into the hundreds. At one end are fruity vape options like fruit punch and watermelon; at the other are stranger inventions with names such as unicorn milk and Pony on Acid.
To keep imitators away, most makers do not publish what goes into their flavor blends. Whatever you buy, make sure the flavorings are food grade.
Nicotine
E-liquid is sold both with nicotine and without it. Bottles are usually labeled 0mg, 6mg, 12mg, 18mg, 24mg or 32mg. The figure is a concentration in milligrams per milliliter (mg/ml), so each milliliter of liquid holds the stated number of milligrams of nicotine.
Treat liquid nicotine with care, because it is very dangerous. Even a small amount that is swallowed or gets onto your skin can cause vomiting, seizures and death. Wear gloves every time you refill your canister.
Read the label
The simplest habit to take from all this is to check the ingredient list on every bottle of vape juice you buy, so you know what it contains.
For more reading, see our post with 4 fun things to know about the top vape juice brands.