What Ingredients Are Commonly Used in Vape Liquids?

What ingredients are commonly used in vape liquids?

UK vape liquid is simpler than many people expect. It is made from just four ingredients: propylene glycol, vegetable glycerin, food-grade flavourings and optional nicotine, with strict UK rules on what is allowed. There is no tobacco and no burning, so none of the tar from cigarettes.

Each ingredient plays a role in how a vape tastes, feels and performs. Knowing what they are helps you choose a liquid that suits you and understand what you are inhaling. This page explains each of the four ingredients, what the PG and VG ratio does and what UK rules ban from e-liquid.

Let us look at the four ingredients, the PG and VG ratio and the banned additives.

One reassuring point upfront is how short the list is. A legal UK e-liquid is not a mystery cocktail of unknown chemicals. It is a small set of named, tested ingredients, each on the label, which is part of what makes compliant products so different from anything bought outside the regulated market.

The four ingredients

Almost every UK e-liquid uses the same base. Propylene glycol carries the flavour and gives the throat hit, vegetable glycerin produces the vapour and smooths the inhale, flavourings give the taste, while nicotine is optional, which is why a 0mg liquid is simply the same base without nicotine.

• Propylene glycol: thin and clear, it carries flavour and gives the throat hit.
• Vegetable glycerin: thicker and slightly sweet, it makes the vapour and smooths the inhale.
• Flavourings: food-grade concentrates that give the taste, from fruit to tobacco.
• Nicotine: optional, from 0mg up to the UK limit of 20mg per ml.

The nicotine deserves a note. Nicotine in e-liquid comes from tobacco or is made in a lab, though the liquid contains no tobacco leaf and no smoke, while nicotine on its own is not a carcinogen, since the cancer risk from cigarettes comes from burning tobacco rather than from nicotine.

That distinction matters for understanding vaping. Many people assume nicotine is the dangerous part of a cigarette, when it is really the addictive part. The tar and the thousands of combustion chemicals are what cause most of the harm, yet none of those are present in e-liquid.

What the PG and VG ratio does

The balance of the two base liquids shapes the vape. A higher PG mix gives a stronger throat hit and sharper flavour with smaller clouds, while a higher VG mix is smoother with bigger clouds, which is why nicotine salts often use a balanced 50/50 blend suited to pod kits.

That balance is also why nic salts feel smooth even at higher strengths, since the 50/50 base wicks well in small pod devices and keeps the throat hit comfortable. If you find a liquid too harsh or too thin, the PG and VG ratio is usually the thing to adjust, so it is worth checking the ratio when you choose.

You may also see liquids described with small extras, such as a touch of sweetener to lift a dessert or fruit flavour. These are used in small amounts within the same regulated framework. Whatever the recipe, a compliant UK liquid still comes back to the same four core ingredients on the label.

What UK rules ban

Not everything is allowed in a UK e-liquid. Harmful additives such as diacetyl, linked to popcorn lung, plus vitamin E acetate, linked to the EVALI lung injuries, are banned, while every liquid must be tested and notified to the MHRA before sale, with full ingredient labelling required.

Flavourings have to be food grade and pass emissions testing, since some things that are safe to eat behave differently when heated and inhaled. That testing, along with the bans and the labelling rules, is why buying from a legitimate UK retailer matters, as illegal products may skip these checks entirely. The four core ingredients stay the same, though the safety checks are what set compliant liquids apart.

• Banned additives: diacetyl and vitamin E acetate are not permitted.
• Tested and notified: every liquid is checked and registered with the MHRA.
• Food-grade flavours: flavourings must be food grade and pass emissions testing.
• Clear labelling: ingredients and strength must be shown on the bottle.

Freebase nicotine or nic salts?

Where a liquid does contain nicotine, it comes in one of two forms. Freebase nicotine is the traditional type, which can feel harsher on the throat at higher strengths. Nicotine salts are smoother at higher strengths and are absorbed a little faster, which is why they suit people switching from cigarettes.

Both use the same core base of PG, VG and flavourings, while both fall under the same UK rules, including the 20mg per ml cap. The choice is mostly about feel. If you want a higher strength that still feels smooth, nic salts in a balanced base are usually the more comfortable option for an everyday vape.

If you want to dig deeper, see our explainer on whether vaping is regulated in the UK. It pairs well with our guide on what vaping does to your lungs and our look at whether vaping is bad for you.

For the full set of guides, the vaping and health hub brings everything together in one place.

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