VG and PG: a beginner’s guide

Last fact-checked 13 January 2021 | Report a factual error on this article

Confused by the VG and PG symbols on your e-juice? You’re not alone! New and experienced vapers often get confused by the VG/PG of their e liquid, and it’s not always clear which VG/PG is the best choice for them. 

In this guide, we’ll explain what VG/PG ratio means, show you why both Vegetable Glycerine (VG) and Propylene Glycol (PG) are used in e-liquid, and give you some pointers on finding your own personal perfect VG/PG balance! 

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What are VG and PG?

VG (Vegetable Glycerine) and PG (Propylene Glycol) are the main ingredients of e liquid. VG and PG make up the ‘base’ of a vape juice (e-liquid), and different flavourings are added to the base to give each e-liquid brand its own distinctive taste. 

Both vegetable glycerine (VG) and propylene glycol (PG) are used as humectants (a type of additive that helps a product retain its moisture) ^{footnote 1}  in food, pharmaceutical and cosmetic products. VG and PG are food-grade compounds, widely considered safe for human consumption.

The VG/PG balance of an e-liquid completely changes the vaping experience. Depending on the amount of vegetable glycerine and/or propylene glycol in your vape juice, you’ll get a totally different taste, texture, throat hit and vapour thickness, so it’s worth getting a basic understanding of what each compound is and does.

What is VG?

Vegetable Glycerin (VG) is a non-toxic compound derived from vegetable fats like coconut oil and soy oil. It’s not completely flavourless (it’s slightly sweet) but it carries flavour reasonably well, and it tends to be used as the main base for the highest-grade e liquids. 

Vegetable glycerin gives e-liquid vapour its thickness. High VG e liquids give off a good cloud and have a smoother throat hit, making them a natural choice for sub-ohm devices (there are other technical reasons why sub-ohm devices are paired with high VG e liquids - we’ll explain this in a moment). If you buy an e liquid that promises “creaminess”, for instance a custard or cake flavour, it’s most likely going to have a high VG (70VG or higher). 

The downside is that e-liquids with high VG tend to clog your device and burn through coils faster. Vegetable glycerin is a thick liquid, so it takes longer for high VG vape juices to soak into your vape coil. Vegetable glycerin’s sweet taste can potentially ‘crowd out’ subtler flavours, but nowadays most high-quality manufacturers adjust their recipes to allow for this.

You can vape 100% VG e juice, but for new vapers we usually recommend a VG/PG blend, as the flavours in a 100VG e liquid can be harder to detect.

What is PG?

PG, or Propylene Glycol (PG), is a food additive (E1520 on the UK Food Standards Agency’s Approved Additives List), typically used in processed foods like soft drinks and ice creams. It’s also used as a pharmaceutical ingredient in certain medicines and eye drops ^{footnote 2}. 

Propylene Glycol (PG) carries most of the flavour and throat hit in an e liquid. If you’re trying to quit smoking and you’re new to vaping, then e-liquids with a high PG ratio are a good starting point. You’ll get the throat hit you’ve come to expect from a cigarette and there’s no sweetness to it, so you’ll get a much sharper tobacco flavour (…if that’s what you're after).

Propylene Glycol has no taste in and of itself, and it’s a thinner liquid, so high PG e-liquids can hold flavour better than high VG liquids. High PG liquids also produce less vapour, and this impacts the flavour transmission. As a rule, the ‘sharp’ flavoured e-liquids (flavours like cider and tobacco) will have a high PG content. 

Some people are sensitive to propylene glycol, and studies have shown that heavy exposure can cause “ocular and respiratory irritation” ^{footnote 3}. If you find that vaping a high PG e liquid is uncomfortable for you, our recommendation is to switch to a 100% VG alternative. 

All e liquids contain a VG/PG base and flavourings, but e liquids can also contain a fourth ingredient: nicotine. Our advice is that — unless you’re quitting tobacco — you should avoid adding nicotine to your vape juice. Nicotine is highly addictive (vegetable glycerine and propylene glycol are not addictive) — we explain the addictive properties of nicotine in this article.  

Is VG/PG liquid safe?

The current scientific evidence suggests that e liquid is very safe, but vaping is still a relatively new thing, and more research is needed. Here’s what we know so far:  

• Current guidance from the NHS is that vaping is at least 95% less harmful than smoking ^{footnote 4}, and Public Health England (PHE) have confirmed that “there have been no identified health risks of passive vaping to bystanders” ^{footnote 5}. 
• Both vegetable glycerine and propylene glycol are widely considered safe for human consumption. VG and PG compounds have been used in the food and pharmaceutical industries for decades, but because of the new way in which these compounds are entering the human body (as vapour rather than liquid, going into the lungs rather than the stomach), these compounds need to be thoroughly studied all over again to be 100% sure that they’re safe.
• We still haven’t seen enough academic research into how safe vapourised vegetable glycerine and propylene glycol are for humans, but a recent inhalation study in lab rats showed “no signs of toxicity” and “no adverse effects ^{footnote 6}.”
• It’s also important to mention that e liquids are regulated in the UK. E liquids all need to be emissions tested, and the ingredients need to meet certain safety standards ^{footnote 7}.
• Public Health England conducts regular independent reports on vaping (you can see the March 2020 report here), and there are plans to carry out a “comprehensive e-cigarette safety review” in the future, so watch this space - we might have more concrete information in the near future.

What does VG PG Ratio Mean?

The VG PG ratio just refers to the amount of VG, relative to the amount of PG, in any given e-liquid. 

A wide range of VG/PG ratios are for sale, but the most common ones are probably 50:50 (50% vegetable glycerin and 50% propylene glycol), 70:30 (70% VG, 30% PG), and 100VG (100% vegetable glycerin). 

If you’re a new vaper, you don’t need to watch the VG/PG ratios too closely - you really only need to know if you prefer ‘high PG’ or ‘high VG’. While there is a noticeable difference between 70VG and 80VG juices, for instance, it’s very small compared to the nuance and complexity that an e-liquid manufacturer can achieve with different flavourings. If a manufacturer can achieve a better taste by adjusting the VG/PG ratio of a new e-liquid, they’ll usually do so. The e-liquid label will always show you the VG/PG ratio, so you’ll always know what you’re vaping, and if you have any concerns, you can get in touch with us. 

Do I have to pick a nicotine booster with the same PG VG as my shortfill?

When our customers add 3mg /6mg nicotine boosters to their standard e-liquid order, we personally pair their shortfill juice with the most appropriate nicotine shot available. Sometimes the nicotine booster has an identical VG/PG, and sometimes it’s a high VG solution with a slightly different ratio. You can learn more about how nicotine boosters interact with shortfill in our recent shortfill guide. 

Handy VG / PG Picking Guide

If you’re a newcomer to vaping, there’s an easy way to figure out your likely VG/PG preference without spending a fortune. Just read this list and see which of the following statements you agree with! It will give you a feel for what VG/PG ratio is probably right for you. 

This table will point you in the right direction, but only you can decide the perfect balance for you:

* A throat hit is very different from throat irritation. If vaping is making your throat itch, you could be PG sensitive, and you might need to switch to a 100VG e liquid. 

** If you use a sub ohm device you usually need a high VG e liquid. If in any doubt about what your machine can handle, take a look at the device packaging and instructions for guidance.

In summary…

That’s it! Hopefully we’ve given you a basic understanding of how vegetable glycerin and propylene glycol work. Remember to pick the ratio that’s best for your health first (if you’re sensitive to PG it’s 100VG all the way), your device second (sub ohm devices need high VG), and your personal taste next (don’t worry - there are hundreds of delicious premium e-liquids to choose from at every VG/PG level). 

If you have any questions at all about how VG/PG ratios work, please please get in touch. 

Stay safe and happy vaping!

 - John Boughey

Links & Citations

Footnote 1:

Collins Dictionary defines ‘Humectant’ as “a substance, as glycerol, added or applied to another to help it retain moisture” - see the link below:

https://www.collinsdictionary.com/dictionary/english/humectant

Footnote 2:

In pharmaceutical terms, PG is classed as a “biocompatible organic solvent” (ref. The Textbook of Pharmaceutical Medicine edited by John P. Griffin) - it aids with drug solubility. 

Footnote 3:

There has been some research done on exposure to PG in high volumes, and the results showed that “exposure to high concentrations of propylene glycol in workplaces and public places may cause ocular and respiratory irritation, and that sensitive subjects should be protected or avoid extreme or prolonged exposure.” (ref. Experimental exposure to propylene glycol mist in aviation emergency training: acute ocular and respiratory effects by G Wieslandera, D Norbäcka and T Lindgrena - more information at the link below).

https://oem.bmj.com/content/58/10/649

Footnote 4:

“In the UK e-cigarettes are tightly regulated for safety and quality. They aren't completely risk-free, but they carry a small fraction of the risk of cigarettes. E-cigarettes don't contain tobacco and don't produce carbon monoxide, two of the most harmful constituents in cigarette smoke. The liquid and vapour contain some potentially harmful chemicals also found in cigarette smoke but at much lower levels.” More information can be found on the NHS website at the link below:

https://www.nhs.uk/smokefree/help-and-advice/e-cigarettes

Footnote 5:

Public Health England have stated that “Our 2018 report found there have been no identified health risks of passive vaping to bystanders and our 2022 report will review the evidence again.” (see section 6 of the link below).

https://publichealthmatters.blog.gov.uk/2020/03/05/8-things-to-know-about-e-cigarettes/

Footnote 6:

The full quote from the 90 day VG/PG inhalation study in rats (Toxicity of the main electronic cigarette components, propylene glycol, glycerin, and nicotine, in Sprague-Dawley rats in a 90-day OECD inhalation study complemented by molecular endpoints, Phillips, Titz et al.) is shown below. Rats were exposed to aerosolized VG/PG for 90 days, some with nicotine and some without. The full study report makes for heavy reading, but you can find it here:

https://www.sciencedirect.com/science/article/pii/S0278691517305112

“A 90-day rat inhalation study according to OECD TG 413 (OECD, 2009b) for the toxicological assessment of nebulized PG/VG aerosols with and without nicotine was conducted. Standard toxicological endpoints were complemented with systems toxicological analyses using transcriptomics, proteomics, and lipidomics of lung tissue, liver tissue, and serum. Both standard and systems toxicology endpoints demonstrated very limited biological effects of PG/VG aerosol with no signs of toxicity. Systems toxicology analyses detected biological effects of nicotine exposure, which included up-regulation of the xenobiotic-metabolizing enzymes Cyp1a1 and Fmo3 in the lung and metabolic effects, likely interlinked with a generalized stress response to nicotine present in the exposure aerosols.

Altogether, under the conditions of this 90-day SD rat study, several nicotine related responses have been observed but taking in to account the overall weight of evidence no adverse effects were observed for PG/VG/nicotine up to 438/544/6.7 mg/kg/day, since the vast majority of the effects observed are considered to be adaptive changes caused by the nicotine levels and they have been shown to be reversible on cessation of treatment.”

Footnote 7:

For a broad view of e-cigarette regulations in the UK, take a look at section 6 of the “Tobacco and Related Products Regulations 2016”:

http://www.legislation.gov.uk/uksi/2016/507/part/6/made

No e-liquid can be sold on the UK market if it has any ingredients which are ‘carcinogenic, mutagenic or reprotoxic’ in unburnt form. This is explained at the link below:

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/682739/Ingredient_guidance_final_draft_011116.pdf

The rules governing emissions testing of e liquids are explained at the link below:

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/544094/3_Emissions_disc_paper_final.pdf