PG vs. VG: What are they & what do they do? 

This blog post is heavily inspired by the UK based Decadent Vapor of the same title.

The two most common ingredients in e-liquid are Propylene Glycol (PG) and Vegetable Glycerine (VG). These form the base of the e-liquid, to which the flavour concentrate and nicotine (optional) is added.

Commonly, e-liquid will be made from a combination of both PG and VG and the ratio is usually stated on the bottle (eg. 70VG/30PG). But what are Propylene Glycol and Vegetable Glycerine? In this quick and easy guide, we explain what they are, the differences between them, and the benefits of each, so you can decide which ratio will work best for you.

What is PG and VG in e-liquid?

Propylene Glycol (PG) and Vegetable Glycerine (VG) form the base of all e-liquids and affect the liquid’s thickness, flavour intensity, throat-hit and vapour production.

Different e-liquids have different PG/VG ratios. The PG/VG ratio you need will be determined by your device and coil setup, as well as your personal preference.

What’s the difference between PG and VG?

What is Propylene Glycol (PG)?

• Propylene Glycol is a colourless and odourless synthetic liquid used as a base for e-liquid.
• PG produces a much stronger ‘throat-hit’ than VG, mimicking the sensation of smoking. Due to this, you will rarely see an e-liquid with a higher PG ratio of 70% as the vape becomes too harsh.
• It has a thinner consistency than VG.
• It is often considered a ‘flavour carrier’, as its presence helps boost the flavours added to it.
• PG is a common ingredient in many foods and products that you use daily, such as toothpaste, soft drinks, bread and dairy products where it is used as an antioxidant, moisture preserver and stabilizer. It is also used in fog machines to create artificial stage smoke.
• The Food and Drug Administration (FDA) has classified propylene glycol as “generally recognized as safe”.

What is Vegetable Glycerine (VG)?

• Vegetable Glycerine is a colourless and odourless natural, syrup-like liquid extracted from vegetable oils.
• VG produces more vapour than PG and has a smoother ‘throat-hit’, making it ideal for ‘cloud-chasing’ with a sub-ohm device.
• It has a thicker consistency than PG. Due to this, you will rarely see an e-liquid with a higher VG ratio of 80% as the liquid becomes extremely thick and clogs up coils.
• VG has a slightly sweet taste which can have a small effect on the overall taste of the e-liquid.
• VG is commonly found in food, cosmetic and pharmaceutical products, as it provides several benefits. For example, VG provides a sweet taste and can stop ice crystals from forming in frozen foods such as ice cream.
• The FDA has classified vegetable glycerine as “generally recognised as safe”.

The more VG there is in the e-liquid, the longer it’ll take for it to absorb into the wick. This is because the thicker consistency e-liquid takes longer to absorb into the wicking material inside the coil. Make sure you’ve given it enough time to absorb between puffs, or you risk having a nasty ‘dry hit’.

Most common e-liquid ratios

What is the best PG/VG ratio?

The PG/VG ratio you use will depend on what vaping device and coil pairing you have.

Mouth-to-Lung (MTL) devices with coils that have a resistance of above 1ohm (Ω) tend to work best with e-liquids that are made up of 60% VG or less. 

Above 60% VG the liquid becomes too thick for these coils, causing them to clog up and stop working. Therefore, e-liquids with ratios such as 50PG/50VG or 40PG/60VG would be the best choice for these devices.

Direct-to-Lung (DTL) and Sub-Ohm devices typically have coils that have a resistance of less than 1ohm (Ω) and work best with e-liquids that are made up of 70% VG or more.

These coils are designed to work well with thicker VG heavy e-liquids. The higher VG content, paired with low resistance coils, produces far larger and denser vapour clouds. Shortfills with a high VG ratio would be the best choice.

This is a general rule-of-thumb, but you may find some newer coils designed for MTL vaping can accommodate higher VG e-liquids

What is the best PG/VG ratio for flavour?

There is a reason why many vapers move towards sub-ohm devices as they become more experienced, and that is flavour (and big clouds!).

Although PG is a ‘flavour carrier’, the flavour intensity of higher-PG e-liquids are hindered by the device and coil used. In comparison, sub-ohm devices paired with higher VG e-liquid, produce double the vapour and thus double the flavour! 

Some people find different PG/VG ratios work well with different flavour types. For example, the sweetness and full-bodied thick vape of VG compliment the custardy sweet dessert flavours, whilst PG brings out the best in fruit and tobacco flavours.

Are PG and VG safe to vape?

Propylene Glycol and Vegetable Glycerine have been consumed by humans for decades. Both are considered safe for human consumption by US, European and UK food authorities. In fact, PG and VG are common ingredients in many foods, cosmetic and pharmaceutical products.

PG Sensitivity 

If you have just made the switch to vaping, it is likely vaping e-liquid containing PG will cause a dry mouth and sore throat so it is important to stay hydrated. Some people may experience a cough, which will subside within a few weeks.

Conclusion

• Propylene Glycol (PG) and Vegetable Glycerine (VG) form the base of the e-liquid, to which flavour and nicotine are added.
• E-liquid contains a mixture of both PG and VG, with the ratio stated on the bottle.
• The PG/VG ratio you need depends on your personal preference and the coil resistance used.
• Higher VG liquids work better with lower resistance coils (less than 1ohm), whilst 50/50 e-liquids work well with higher resistance coils (more than 1ohm).
• High VG e-liquids produce more vapour and have a smoother throat-hit, but the liquid is thick and can clog up coils quickly.
• E-liquids with more PG give more of a throat-hit and a sharper flavour. The liquid is thinner than VG, making it ideal for use with coils above 1ohm.
• VG heavy e-liquids usually have a nicotine strength of 3mg or less, as anything above this becomes too harsh.
• 50/50 e-liquids come premixed with nicotine up to 18mg.
• For more of a traditional smoking sensation, use an MTL device with a coil of above 1ohm, paired with 50/50 e-liquid.
• For maximum flavour, use a sub-ohm coil and higher VG liquid. You inhale double the vapour, and thus double the flavour!