What are PG and VG?

PG (Propylene Glycol) vs. VG (Vegetable Glycerin)

When it comes to e-juice, two terms constantly you may have seen but are PG and VG. To someone new to vaping, these turns can be confusing but knowledge of these two ingredients can vastly improve your vaping experience. Here’s our easy-to-follow guide on everything you need to know about PG and VG.

What are PG and VG?

PG and VG are the odourless liquids that are combined with flavour and nicotine to create e-juice. They produce vapour when heated, which allow them to be inhaled. The two fluids have a different consistency to each other, and also have a slightly different taste. They have distinct mouth and throat sensations when vaped. Most modern e-liquid uses a combination of the two fluids, though the ratio can vary dramatically. Some vaping set-ups can only work with a certain level of PG and VG. Choosing the wrong PG/VG ratio can put first timers off so be careful to choose the right level for your equipment.

So exactly is PG?

PG stands for Propylene Glycol, a petroleum by product. The fluid has no odour or colour, and is less viscous than VG. In vaping it is used to provide a ‘throat hit’, which some users claim is similar to the sensation experienced when smoking tobacco. It also carries flavour more effectively than VG, meaning it’s the most commonly used suspension fluid for flavour concentrates and nicotine.​

But is it safe?

Studies have shown that PG is safe to ingest orally, and the FDA has deemed it ‘generally recognised as safe’ to be used as a food additive. However, most studies into the safety of propylene glycol look at ingestion, rather than consuming it in aerosol form. Of the limited studies that exist, a long-term experiment held in 1947 judged that inhaling PG was ‘completely harmless’.

While PG is regarded as safe for humans, it can cause serious harm to pets. It is generally regarded as safe as a food additive for dogs, but has been linked to Heinz body anaemia in cats. Be careful when vaping around pets, particularly if you have cats and use PG in your e-liquid.

PG – What to be aware of

Some people find a high level of PG irritating to the throat. Allergies to PG are rare, but have been reported. If you find yourself coming out in a rash, or suffering other unpleasant reactions after using PG based e-fluid, you should look at using 100% VG juice instead. Many vendors are starting to offer this as an option.

The most common side effects of using e-liquid containing propylene glycol are: dry mouth, sore throat and increased thirst. These symptoms usually last anywhere from a few days to a week as the body gets used to the propylene glycol. It is advised to drink more water and liquids then usual for the first few weeks of using your e-cigarette. Be aware that any unusual reactions could be side effects from quitting smoking, and not necessarily because of the PG.

So exactly is VG?

VG stands for Vegetable Glycerin. It is a natural chemical, derived from vegetable oil, so is safe for vegetarians. It is commonly used in e-liquid to give a ‘thick’ sensation to vapour. VG has a slightly sweet taste and is considerably thicker than PG. The hit from a high VG fluid is a lot smoother than with PG, making it more suitable for sub-ohm vaping. While nicotine and flavourings are commonly suspended in PG, some vendors are offering a VG alternative, to enable 100% VG mixes.

But is it safe?

The FDA has classified VG as ‘generally recognised as safe’ and it is widely regarded as one of the most benign substances known to man. The SIDS assessment profile show it to have low toxicity when consumed, and of low potential to irritate the skin or eye. This, along with the widespread use of VG in food and medicine suggest it is safe for humans. However, as with PG, there are limited studies on VG being inhaled as opposed to ingestion.

It is important to note that the risk of being allergic to vegetable glycerin is very low, making it a useful alternative for people who have issues when vaping e-juice containing PG. If you are allergic to palm oil or coconut oil then VG could prove a problem, but this is relatively uncommon. Diabetics could possibly experience problems with metabolising VG, but this would not be an issue at the levels used in vaping.

VG – What to be aware of

The increased thickness of VG means it can reduce the life of atomisers quicker than PG-based juice. High VG liquids clog up coils more rapidly, and will not work well, if at all, in certain tanks. Older products are especially susceptible, particularly models that use smaller coils such as clearomisers. The Nautilus range, Innokin iclears and eGo tanks are some of the more well-known tanks that are known to have difficulties dealing with high VG fluid.

The most common side effect of vaping high VG e-liquid is a dry mouth, sore throat, and increased thirst. Again, be sure to drink plenty of water and take a break from vaping if necessary.

Ok, so what PG/VG ratio should I use?

There isn’t a ‘one size fits all’ answer to this, it basically comes down to personal preference. Many people use various levels of PG and VG for different purposes:

  • Throat Hit – If you enjoy a sharp throat hit when vaping then you’ll prefer a high PG vape. The ‘kick’ at the back of the throat, is something many ex-smokers crave, and PG (along with the nicotine) provides more of this than VG. PG carries flavour marginally better than VG, so the flavour will be slightly improved.
  • Smoothness – High VG fluid tends to give a much smoother feeling on the throat, with a more substantial ‘thicker’ mouthfeel. The flavour is slightly muted in VG fluids, but this can be countered by using more power to produce more vapour. Be careful to stay within the voltage/wattage limits of your atomiser, or you risk dry hits, or even damaging your equipment.
  • Stealth Vaping – If you want to keep your vaping lowkey in public then high PG is the way to go. Less vapour is produced when exhaled, making this ideal for the less ostentatious vaping enthusiast. However, you should always apply common sense. Vaping in certain places, such as waiting rooms and on public transport, is often outlawed and is simply bad manners. As vaping is relatively new, we have a duty to be aware of public opinion and behave responsibly.
  • Cloudchasing – A growing trend in vaping circles is ‘cloudchasing’. This simply involves exhaling dense clouds of vapour, the thicker the better. There are even competitive events based around this activity, where the person producing the biggest clouds wins. If this appeals then high VG is the only option – the higher the better.

So what kind of set-up do I need?

It isn’t as simple as deciding on a high VG or PG fluid and hoping for the best. It all comes down to your equipment. If it isn’t suitable for the job, it can lead to unpleasant throat irritation or wicking problems resulting in dry hits.

  • Clearomizer Tanks – The clearomizer is one of the most common styles of tanks for vaping, and include the Mini Nautilus and the Kanger Protank. These take coils in the 1.2-2.5 ohms range, and are usually vaped below 15w. These are not generally suitable for high VG fluids, as their coils cannot cope well with thick gloopy fluid and can lead to unpleasant dry hits of burning cotton. It is advised to use high PG fluid, or a 50/50 ratio, when using this kind of tank.
  • Sub-Ohm Tanks – These tanks include the Aspire Atlantis and Kanger Subtank among others. They can take a lot more power than standard clearomizers and are designed to deal well with high VG juice. Vaping at this increased battery strength uses up e-fluid a lot quicker than with, so you’ll find your juice going down quicker than with high PG fluids. If you want to know more about this, check our detailed guide to sub-ohm vaping, and some essential advice on battery safety.
  • RDA/Drippers – If you prefer to use a dripper you have a lot more flexibility on your fluid ratio. It still depends on what strength coil you use – sub-ohm coils for high VG, higher ohms coils for high PG – but you don’t have to worry as much about your cotton wicking properly. As ever, the ratio boils down to personal preference, but the norm for dripping tends to be a 30/70 PG/VG mix.

Conclusions…

The basics of PG and VG are quite easy to grasp. They both work in different ways, and each has advantages and disadvantages. Our advice is to start with a 50-50 PG to VG ratio then try out various combinations and see which you prefer. Make sure your vaping set-up can deal with the different ratios.

Many vapers like to use different levels of PG and VG at different times, and with various flavours. Fruits and drink flavours often go well with PG, as the sharpness of the PG blends well with the tart or fizz of the flavouring. Similarly, flavours based on cream, custard and yoghurt tend to work well with high VG as the thick mouth sensation adds to the dessert-like feel. But as ever, there are no fixed rules, just follow what your tastebuds tell you!