The E-Liquids Guide to PG and VG
E-liquids can appear confusing at first, especially if you are just starting out on your vaping journey. Understanding the basics of your e-liquid can help you further tailor your vaping experience.
We are going to look at two of the main ingredients in e-liquids, the diluents. This article will go over what they are, what they are used for and how they affect your vaping experience.
PG and VG are the two diluents used in e-liquids. PG and VG are technically the carrier for the e-liquid, and they are the two major components responsible for the vape clouds which simulate the smoking experience. The heated coil of the e-cigarette device produces an aerosol of predominately PG and VG, but also nicotine and flavourings. This aerosol is inhaled by the vaper, providing satisfying nicotine delivery with a flavoured taste.
PG = Propylene Glycol
VG = Vegetable Glycerine
They are each there to primarily produce a vapour cloud akin to smoking but they also perform different functions that affect your overall vaping experience.
PG: Propylene Glycol
PG is a synthetic liquid with a consistency slightly thicker than water. The PG used in your e-liquid is manufactured on an industrial scale by the reaction of propylene oxide with water. This process produces PG of very high purity, known as pharmaceutical grade.
PG is a colourless liquid, with practically no taste or odour. It’s part of the chemical family known as “diols”, and the chemical structure is similar to an alcohol you might be familiar with, ethanol; found in alcoholic drinks. If you can think back to your school days you might remember from chemistry that “like dissolves like”, meaning PG is readily soluble in water as they share similar chemical properties. The chemical structure of PG means it has a quite high boiling point of 185-189C, so you can imagine your atomizer coil temperature has to get pretty hot to produce vapour!
How does PG effect my vaping experience?
PG has two functions in your e-liquid. It’s the carrier for the flavour/nicotine and is also responsible for the ‘throat hit’ part of your vaping experience.
An e-liquid with a high ratio of PG will give a much more pronounced throat hit when you vape it, this means it is great for people who want to simulate the sensation of smoking. Think of it this way, the chemical properties of PG are ideal to simulate the smoking experience. It produces a vapour density upon heating which is more like the density of cigarette smoke. It’s also a very good solvent in chemistry, meaning the flavours and nicotine are “carried” well in the PG-based aerosol, delivering more nicotine for vapers to experience a more intense throat hit. Remember PG doesn’t really have any taste or odour, so the flavourings really come to life and are not masked by an inherent flavour of the carrier.
What else is PG used for?
Outside of vaping, PG is used in a wide variety of industrial and consumer applications. It’s estimated that the global market for PG in 2019 was $3.8 billion and will rise to $4.7 billion by 2024. The largest market share of PG is used by the food, beverage and pharmaceutical industries. Within the food and cosmetic industries, it is also used as a humectant (retains moisture), preservative and solvent for the formulation of products. Remember we talked about how good a solvent PG is! Such favourable chemical properties make PG the solvent of choice for many medicinal products including injectable, oral and topical formulations. One final interesting fact on PG, it’s used to create artificial smoke or fog for fire-fighter training and theatrical productions.
How safe is PG?
PG has been classified as ‘Generally recognised as safe” by the FDA and WHO. PG has been used in food and consumables for many years and is considered safe by the U.S Food and Drug Administration (FDA) and is approved as a food additive by the UK’s Food Standards Agency (FSA). Propylene glycol is not classified as harmful under European CLP regulation for oral, dermal or inhalation routes of administration. In 2016 the European Chemicals Agency (ECHA) engaged an expert committee to review all of the available toxicology data. This was in response to an EU member state request to reclassify PG as a potential respiratory irritant. After careful consideration, the expert committee concluded that the available data were insufficient to warranty a classification of PG. That’s the science behind the safety of PG, but what about vapers own experiences? The vast majority of existing vapers never experience any problems with the PG ingredient of their e-liquid. For new users, some can experience a dryness of mouth or throat. Remember before when we said PG was used in the food industry as a humectant (moisture retainer), this is because PG absorbs water (hygroscopic). This can cause a bit of mouth/throat dryness and sometimes a tickly cough. The simple solution for a new vaper is to have a drink of water handy. More experienced vapers have learnt to adjust their intact accordingly.
VG: Vegetable Glycerin
VG is known by a few other names, glycerol or glycerine. VG is a sugar alcohol, similar in chemical structure to PG but with one more alcohol (OH) group in the molecule. For this reason, in chemistry it’s known as a triol (3 x OH) whereas PG is a diol (2 x OH). This extra alcohol group means strong chemical forces hold the molecule together. Hence, VG has a very high boiling point (290C) and a syrup-like consistency. It’s a colourless and odourless thick liquid with a subtle sweet taste (remember, sugar alcohol).
How’s VG made? It’s a by-product from various industrial processes involving natural oils, which explains origin of the term “vegetable” glycerine. Typical oils include those derived from rapeseed, soybean and coconut. Once isolated crude it’s then refined through a distillation process to yield high purity, pharma-grade VG used in e-liquid formulations.
How does VG effect my vaping experience?
VG performs a few functions in your vaping experience. It adds a slight sweetness to your e-liquid and is responsible for the majority of vapour production in a PG:VG e-liquid formulation. For reasons we discussed earlier, an e-liquid exclusively composed of PG would be very harsh on the throat. As the amount of VG increases in the e-liquid formulation then you can expect to experience larger clouds of dense vapour. You’ll also be able to taste the underlying sweetness intrinsic to VG.
What else is VG used for?
Outside of e-liquid, VG is primarily utilised in the food, cosmetics and pharmaceutical industries. In the food industry it’s widely used as a sweetener, and as a humectant (moisture retainer) in pharmaceutical and cosmetic formulations. Typical products your familiar with include ice-cream, frozen yoghurt, toothpaste, moisturiser, cough medicine and hand sanitiser.
How safe is VG?
VG has been classified as ‘Generally recognised as safe” by the FDA and WHO. VG has been used in food, cosmetics and medicines for many years and is considered safe by the U.S Food and Drug Administration (FDA) and is approved as a food additive by the UK’s Food Standards Agency (FSA). VG is not classified as harmful under European CLP regulation for oral, dermal or inhalation routes of administration. VG shows very little toxicity and very high doses; greatly in excess of anything possible by vaping, can be tolerated without any issue.
I have allergies, are there any risks?
The majority of vapers; either new or experienced, don’t have any problems with PG/VG e-liquids. However, a minority have reported some minor adverse effects which usually pass with time. E.g. cough, sore or dry throat.
We need to understand that there is a difference between an allergy and a sensitivity. An allergy involves the response of the body’s immune system to something you’ve consumed, like a component of a food or even a medicine. Whereas a sensitivity doesn’t involve the immune system and is an exaggeration of the normal effects of the substance. E.g. caffeine in a cup of coffee may cause extreme symptoms of palpitations in a small number of people. It’s still not clear as to the definitive cause of sensitivities. From online vaping polls and the feedback of our own customers, sensitivity to PG is more likely than for VG. As PG is a component of many consumer products we use on a daily basis, people with a genuine allergy to PG (often through skin contact) are usually aware of it and should avoid high PG ratio e-liquids. Minor symptoms experienced by some vapers are much more likely to be sensitivities rather than allergies.
Surveys indicate about 1 in 10 vapers may experience a PG sensitivity. Typical symptoms include dry/sore throat and cough, although often these symptoms fade with time which casts doubt as to whether the vapers in question are truly sensitive to PG.If you experience a suspected adverse reaction; beyond the more common short-term symptoms described, then discontinue use and contact the manufacturer of your e-liquid. Regulation of vaping products in the UK requires manufacturers to collect and monitor information about suspected adverse reactions on human health. Seek medical advice if necessary.
There is technically no ‘best’ PG:VG ratio. It all boils down to what you want out of your vaping experience as each of the diluents provide different things.
If you want maximum flavour out of your e-liquid, you want to choose an e-liquid with a balanced PG:VG ratio, so look out for a 50:50 ratio. Or favour PG in the e-liquid, so an e-liquid with a PG:VG ratio around 60:40. Just remember if you are choosing an e-liquid with a higher PG ratio, that the throat hit will be more pronounced.
Any e-liquid with a high PG ratio will have a more pronounced throat hit. So, look for PG:VG ratios around 60:40 or 70:30.
For bigger clouds of vapour you need to look for a vape juice with high VG content. A PG:VG ratio around 30:70 or 20:80 will give you a much thicker e-liquid that produced dense clouds of vapour. Keep in mind; this e-liquid is much thicker, so is not suitable for all e-cigs. It is best suited if you have a sub-ohm vaping set up.
For discreet vaping without losing flavour or vapour production, it is best to stick to a 50:50 PG:VG ratio. You are basically getting the best of both worlds, without too much of either. Totally Wicked’s Red Label e-liquid is a market-leading 50:50 ratio e-liquid.
If you can’t find a pre-mixed e-liquid that fits all of your criteria, you can always start mixing your own e-liquid. This gives you the freedom and control to completely tailor your e-liquid to your needs. You can find everything you need to mix your own e-liquid at Totally Wicked.
Why do some PG:VG diluents also contain a minor component of deionised water?
Some e-liquids can still be quite thick (viscous) even at 50:50 PG:VG ratio. If you’re new to vaping and using a starter device then the chances are your atomizer e-liquid inlet holes are quite small. This can sometimes cause problems for wicking the atomizer cotton and impact on your vaping experience. A small percentage of deionised water acts as a viscosity modifier, reducing the thickness of the e-liquid to aid wicking of the cotton.
Yes and no. While every type of e-liquid will work in all e-cigs and vape mods, you might not get the best vaping experience unless you tailor your e-liquid to your e-cig.
High VG e-liquids
If you have an e-liquid that has a high VG content, you ideally want an e-cig with sub-ohm coils and higher powers. The sub-ohm coils have larger e-liquid inlet holes, so it won’t struggle to wick this much thicker e-liquid. Also, with higher powers you can get much larger clouds of vapour.
High PG e-liquids
If you have an e-liquid with a high PG content, you want higher resistance coils and much lower powers. If you put a high PG e-liquid into an atomizer head with much larger e-liquid inlet holes, it will wick too quickly as is it much thinner and it can lead to leaking. Also, the higher resistance coils and lower powers mean you are not going to experience too much throat hit.