what is in a vape

What Is in a Vape?

A complete breakdown of e-liquid ingredients, device components and what you are actually inhaling.

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Quick answer: UK e-liquids contain four main ingredients: propylene glycol (PG), vegetable glycerin (VG), food-grade flavourings and optionally nicotine. The device itself contains a battery, a heating coil and a reservoir or pod for the liquid. None of the standard ingredients involve tobacco or combustion byproducts.

Understanding what is actually in a vape is important for making informed choices about your health and your products. The good news is that TPD-compliant UK e-liquids have clear and limited ingredient lists. Here is a full breakdown.

E-Liquid Ingredients

Ingredient What it is Role in e-liquid Typical proportion
Propylene Glycol (PG) Synthetic liquid derived from petroleum or plant material; widely used in food and medicine Carries flavour compounds, produces throat hit, thinner consistency 20 to 50% (varies by formula)
Vegetable Glycerin (VG) Natural liquid from plant oils (soya, coconut, palm); food-grade Produces vapour clouds, slightly sweet, thicker consistency 50 to 80% (varies by formula)
Flavourings Food-grade flavour compounds; same type used in food manufacturing Taste and aroma 5 to 15%
Nicotine (optional) Extracted from tobacco plant or synthetically produced; pharmaceutical grade Nicotine delivery 0 to 2% (0 to 20mg/ml: UK maximum)

What Is Not in UK E-Liquids

This is as important as what is in them. UK TPD-compliant e-liquids do not contain:

  • Tobacco: no tobacco leaf or tobacco combustion products
  • Tar: produced only by combustion, which vaping does not involve
  • Carbon monoxide: a byproduct of burning
  • Diacetyl: banned in UK e-liquids since 2016 (previously linked to lung disease in occupational exposure)
  • Vitamin E acetate: the additive linked to the US EVALI outbreak in 2019; not permitted in UK liquids
  • Water: contrary to popular belief, the visible "vapour" is not water vapour; it is aerosolised PG and VG droplets

PG vs VG: What the Ratio Means

How PG/VG ratio affects the vaping experience

Higher PG = more throat hit, more flavour, less cloud. Higher VG = more cloud, smoother, less flavour intensity.

Throat hit
More PG = more hit
Vapour cloud
More VG = more cloud
Flavour intensity
More PG = more flavour

Blue = PG contribution, grey = VG contribution. A 70VG/30PG liquid suits most beginners and nic salt users.

What Is Inside the Device Itself?

The physical vaping device contains several components:

  • Battery: rechargeable lithium-ion cell providing power
  • Coil / atomiser: a resistive wire heating element wrapped around a wicking material; heats e-liquid to vaporise it
  • Wick: typically organic cotton; draws liquid from the reservoir to the coil
  • Pod or tank: the reservoir that holds the e-liquid
  • Airflow system: controls how much air mixes with the vapour
  • Mouthpiece: the opening you inhale from

Frequently Asked Questions

PG is classified as generally recognised as safe (GRAS) by food regulators worldwide and is used in food, medicine and cosmetics. Inhaled PG has been studied in the context of stage fog machines and medical nebulisers. At the concentrations used in vaping, it is not considered acutely toxic, though some individuals have a sensitivity that causes throat irritation. Long-term inhalation studies specifically for vaping are ongoing.
Flavourings used in UK e-liquids are food-grade compounds: the same types used in food manufacturing. They are safe to eat. The question for vaping is whether inhalation of the same compounds over the long term carries different risks than ingestion. For most common flavourings this appears to be a low risk, but diacetyl (previously used in some flavourings) was banned specifically because of inhalation concerns. TPD-compliant liquids must not contain diacetyl.
The visible aerosol from vaping is primarily aerosolised VG droplets: VG produces the most visible cloud because it does not evaporate as quickly as PG. PG, nicotine and flavouring compounds are also present in the aerosol but less visible. Most of the aerosol condenses rapidly when exhaled, which is why vapour dissipates so much faster than tobacco smoke.
Synthetic nicotine (also called tobacco-free nicotine or TFN) is nicotine manufactured in a laboratory rather than extracted from tobacco plants. It is chemically identical to plant-derived nicotine. Some e-liquid manufacturers use synthetic nicotine to produce a product that contains no tobacco-derived ingredients. It is regulated in the same way as tobacco-derived nicotine in the UK under TPD rules.

Browse our full range of TPD-compliant e-liquids at Celtic Vapours

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