PG stands for propylene glycol and VG for vegetable glycerine. These liquids form the base of many e-liquid formulations, carrying flavourings and any nicotine. The ratio describes their proportions. This guide is for existing adult smokers and existing adult vapers aged 18 or over in the UK.
What is PG?
Propylene glycol is a clear, colourless liquid used as a solvent and carrier in e-liquid. It is less viscous than vegetable glycerine.
PG is an organic compound, not an oil. The finished e-liquid may also contain flavourings, nicotine and other ingredients declared by the manufacturer.
PG also has uses in food, cosmetics and medicines. Those uses do not establish the safety of inhaling an e-liquid.
What is VG?
Vegetable glycerine is a clear, colourless liquid that is more viscous than PG.
VG may also be labelled vegetable glycerin or glycerol. Vegetable glycerine is derived from plant oils, but glycerine itself is not an oil.
Its viscosity affects how a formulation moves through a pod or tank and reaches the coil. Compatibility depends on the finished liquid and the hardware’s design.
VG forms part of the liquid base and the aerosol produced when the device heats e-liquid. Aerosol output also depends on the device, power, coil and use.
What is the difference between PG and VG?
The principal practical difference is viscosity: VG is thicker than PG. The table summarises their roles in the liquid base.
Neither ingredient is nicotine, and neither is a flavouring. They form the base that holds the flavourings and any nicotine included in the finished formulation.
|
Property |
PG |
VG |
|
Full name |
Propylene glycol |
Vegetable glycerine |
|
Origin |
Synthetic organic compound |
Derived from plant oils |
|
Viscosity |
Lower viscosity and thinner |
Higher viscosity and thicker |
|
Flavour carrying |
Used as a solvent and carrier |
Forms part of the base carrying flavourings |
|
Aerosol output |
Depends on the full formulation and device |
Depends on the full formulation and device |
|
Inherent taste |
Taste depends on the finished formulation |
Glycerine has a naturally sweet taste |
|
Typical e-liquid use |
Commonly forms an equal share of 50:50 liquids |
Commonly forms the larger share of high-VG liquids |
E-liquid must reach a coil’s wicking material before it is heated. A thicker formulation can move through that material differently from a thinner one.
The ratio is one compatibility factor. Check it alongside the device and coil instructions rather than treating it as a measure of quality.
What does the PG/VG ratio on a bottle mean?
The PG/VG ratio states how much propylene glycol and vegetable glycerine make up the e-liquid base.
A 50:50 liquid contains equal proportions of PG and VG. A 30:70 PG/VG liquid contains 30% PG and 70% VG.
The order of the figures requires attention because labelling is not consistent across the e-liquid industry. Some manufacturers state PG first, while others state VG first. The numbers cannot be interpreted correctly without checking which ingredient appears beside each one.
For example:
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30:70 PG/VG means 30% propylene glycol and 70% vegetable glycerine.
-
70:30 VG/PG also means 70% vegetable glycerine and 30% propylene glycol.
These two labels describe the same proportions, even though the ingredients appear in a different order.
Dinner Lady shortfill e-liquids use more than one ratio; check the specific product label rather than applying one ratio to the whole range.
Always look for "PG/VG" or "VG/PG" beside the ratio instead of assuming that the first number represents a particular ingredient. Where a product page displays only two numbers, its specification should identify the order used.
What does 50/50 PG/VG mean?
A 50/50 PG/VG label means that the e-liquid base contains equal proportions of propylene glycol and vegetable glycerine.
Because both ingredients account for half of the base, the order makes no numerical difference in this particular ratio. "50:50 PG/VG" and "50:50 VG/PG" describe the same proportions.
A 50:50 formulation is used in many 10ml e-liquids for compatible refillable mouth-to-lung devices. Dinner Lady Bar Salts are one example.
Compatibility still depends on the specific pod, coil and device. Existing adult vapers should check the manufacturer's product information rather than using the ratio as the only compatibility measure.
Our nic salts and freebase guide explains how nicotine form differs from the PG/VG ratio.
Why are PG and VG blended rather than used alone?
Blending PG and VG allows manufacturers to adjust the base’s viscosity and other formulation properties.
The final specification must account for the other ingredients as well as the intended hardware. The base ratio does not describe nicotine strength.
The ratio is therefore a technical part of the formulation rather than a grade or indication of product quality.
Which PG/VG ratios are commonly available?
Examples include 50:50, 30:70 and 40:60 PG/VG. These are formulations, not a ranking of product quality.
Dinner Lady Bar Salts use 50:50 PG/VG. The brand also lists 30:70 shortfills and a 40:60 Dessert Bar shortfill format. Ratios and bottle formats should be checked on the individual product page.
For device pairing, coil resistance and power considerations, read our guide to e-liquid ratios for MTL and sub-ohm vaping. Our Dinner Lady e-liquids range guide provides a broader overview of the available formats.
Are PG and VG regulated in UK e-liquids?
UK regulations place notification, ingredient, container and labelling requirements on nicotine-containing e-liquids before they can be sold.
The Medicines and Healthcare products Regulatory Agency is the competent authority for the UK notification scheme covering nicotine-containing vaping products. Under the Tobacco and Related Products Regulations 2016, e-cigarettes and refill containers must be notified to the MHRA and published before they can be sold.
The regulations also:
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Limit an e-cigarette tank to a maximum capacity of 2ml
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Restrict a nicotine-containing refill container sold to consumers to 10ml
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Cap nicotine strength at 20mg/ml
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Require nicotine-containing products or their packaging to be child-resistant and tamper-evident
-
Ban certain ingredients, including colouring, caffeine and taurine
-
Set labelling and warning requirements
The full requirements are set out in the MHRA e-cigarette and vape products guidance hub.
Vaping Products Duty is separate from the product rules. It starts on Oct 1, 2026 at £2.20 per 10ml and is based on liquid volume rather than PG/VG ratio. Eligible pre-start production or imports may be sold unstamped until Mar 31, 2027. See our UK vape tax guide and HMRC’s retail guidance.
Which devices use higher-VG e-liquids?
Higher-VG formulations are used with hardware designed to handle their greater viscosity. Follow the specified liquid ratio and nicotine range for the exact device and coil.
A higher-VG liquid may not wick as intended in a pod designed for a thinner formulation. Equally, a coil’s resistance alone does not determine the liquid it accepts.
How should you store e-liquid?
Correct storage keeps e-liquid sealed and protected from heat, direct sunlight and unintended access.
Keep each bottle upright with its cap closed. Store it away from radiators, windows, vehicles exposed to heat and other locations where temperatures can rise. All e-liquids must remain out of reach of children and pets.
Temperature affects viscosity. Higher-VG e-liquids are already more viscous than 50:50 formulations and become thicker at lower temperatures. If a stored bottle has been exposed to cold conditions, follow the product and device instructions before using it.
Use the best-before information printed on the bottle instead of relying on a general estimate. Check that the bottle, cap and nozzle remain intact, and follow any additional storage directions provided on the label.
Frequently asked questions
Is the first number PG or VG?
Either. Check the letters beside the figures: 30:70 PG/VG and 70:30 VG/PG both describe 30% PG and 70% VG.
Which is thicker, PG or VG?
VG is more viscous than PG. The finished liquid’s consistency also depends on the other ingredients and temperature.
Are 100% VG e-liquids available?
Yes. Some UK e-liquids are labelled 100% VG or PG-free. This describes their base or formulation; a flavoured product is not necessarily pure glycerine. Check the ingredients and device compatibility. Raw glycerine and mixing ingredients should not be treated as ready-to-use e-liquid.
Are PG and VG the same as nicotine?
No. PG and VG are base ingredients. Nicotine is a separate ingredient, with its concentration stated on nicotine-containing products.
This article is for existing adult smokers and existing adult vapers aged 18 or over in the UK. Nicotine-containing e-liquids contain nicotine, which is a highly addictive substance.
