What is actually in e-liquid? The four ingredients, explained

Most e-liquids have a remarkably short ingredient list. PG and VG make up the bulk of the bottle and act as the base that carries everything else. Flavouring is added on top, typically a blend of several food-grade flavour compounds. Nicotine, if there is any, is a small fraction of the total.

That is worth knowing because it makes the label easy to read. The ratio tells you about the base, the flavour description tells you what has been added, and the milligram figure tells you the nicotine. Even a 20mg liquid, the strongest you can legally buy in the UK, is only about 2% nicotine by volume.

Propylene glycol (PG) is a thin, clear liquid widely used in food and medicines. In e-liquid it carries flavour well and adds to the throat hit. Vegetable glycerine (VG) is a thick, slightly sweet liquid made from plant oils, and it is what makes dense vapour.

Neither is an oil in the way cooking oil is: VG is glycerine, which dissolves in water. The balance between the two is shown on the label as a ratio, usually VG first. If you ever mix your own, plain VG and PG bases let you set the ratio yourself. The table shows how they compare.

Flavour is where e-liquid makers earn their reputations. A single fruit flavour might combine several flavour compounds to get the taste right, and a dessert might use many more. These are typically food-grade flavourings, the same kind used in sweets and drinks, though food-grade means safe to eat, not proven safe to inhale.

Two extras turn up often. Sweeteners, usually sucralose, make liquids taste richer but leave residue on coils. Cooling agents give ice flavours their cold feel; many do not taste of mint at all, which is why a mango ice can feel freezing without tasting like toothpaste. Clear liquids without sweetener are kinder to coils.

The milligram figure on a bottle is milligrams of nicotine per ml of liquid. So a 10ml bottle of 18mg contains 180mg in total, and a 10ml bottle of 3mg contains 30mg. The maths is that simple, and it explains why the same bottle lasts very different amounts of time for different vapers.

Nicotine is addictive, which is why every nicotine bottle in the UK carries a warning. If you want the flavour and the habit without nicotine, a nicotine-free liquid is the same base and flavouring with nothing added. Shortfill vapers add nicotine separately with nic shots, usually 18mg.

Nicotine e-liquid sold in the UK falls under the Tobacco and Related Products Regulations 2016. Products have to be notified to the MHRA before they go on sale, bottles need a child-resistant and tamper-evident cap, and a number of additives are banned outright, including vitamins, caffeine, taurine and colourings.

The label must also carry certain information, which makes it easy to check you have a legitimate product. Look for the items below on any nicotine bottle. If a bottle is missing them, or holds more than 10ml with nicotine in it, it is not compliant with UK rules and is best avoided.

E-liquid attracts more rumours than almost anything else in vaping, partly because most people never look closely at the label. Some myths make liquids sound scarier than they are; others make them sound harmless, which is not right either. Vaping is not risk-free.

Flip the cards for the facts. If you want to understand how the nicotine form affects the feel, our guide to nic salts and freebase covers it, and our throat hit guide shows how PG and VG change the sensation on every puff. Reading the label properly is the quickest way to cut through the rumours.

A last question to check the label-reading has stuck. This is the exact kind of decision you make every time you buy a new bottle, so it is worth having the logic straight. Look at the ratio first, then the device it is going into.

Choose one and check the reasoning below it. Once you can match a ratio to a device without thinking, you will rarely buy a bottle that floods your pod or tastes thin in your tank, and you will spend far less time wondering why a liquid that everyone raves about does not work for you.