Updated: August 2022
Pick up any e-liquid bottle and you’ll typically see letters VG:PG. The VG refers to vegetable glycerine, one of the key ingredients used in almost every e-liquid. In this article we’ll cover what vegetable glycerine is, how it is different from propylene glycol and other frequently asked questions.
Contents
- What is vegetable glycerine?
- Why is it used in e-liquid?
- Is VG bad for coils?
- Can you use VG as an alternative to PG?
- Is vegetable glycerine safe?
- What else is VG used for?
- Related posts
- Related categories
| Chemical name | HOH₂C–CHOH–CH₂OH |
| Food code | E422 |
| Also called | Glycol, Glycerine |
| Properties | Colourless, viscous, odourless, slightly sweet. |
| Derivative of | Rapeseed, palm or sunflower oil or via propylene or propenel |
VG stands for Vegetable Glycerine. It is a clear, odourless liquid that is derived from vegetable oil.
VG is classified as a sugar alcohol, although it has no inebriating effects, and has a slightly sweet taste. Like PG, it is not an oil - that’s important, as inhaling oils can cause Lipoid Pneumonia. It’s also similar to PG in that when heated it produces a vapour that resembles smoke.
When in its natural form, it is derived from vegetable sources, but can also be created as a byproduct from the production of biodiesel. While the form of glycerine used in e-liquid is vegetable, glycerine can also be made from animal fats.
VG, along with PG, creates vapour when heated. Rao et al have also shown that they enhance sweetness, reduce bitterness and appear to accentuate the pleasantness of some flavours. A 2021 study has also shown that VG combined with PG has anti-bacterial properties.
There are differences in the properties of VG and PG when used in e-liquid. The vapour from VG is thicker and denser than that from PG. It’s also smoother on the back of the throat. Some vapers feel that VG doesn’t carry flavour as well as PG, but that’s usually balanced out by the fact you get more vapour from high VG e-liquids.
Because of these differences most e-liquids contain both VG and PG to gain a balance between the two different properties. For vapers who prefer high wattage vaping with thick clouds of vaper, the VG level will be increased. For vapers who prefer a stronger throat hit, the level of PG is increased.
Read more: VG v. PG: What’s the difference?
Because VG is thicker than PG, it can be harder on the coils. Because of this, many e-liquids use a blend of VG and PG. High VG e-liquids, such as those with a VG:PG ratio of 60:40 or greater, are usually used with coils which have been designed with larger ports which can handle the thicker e-liquids.
A few years ago there was concern about people being allergic to PG. In reality this seems to have been over-egged.
Some people may be sensitive to PG, but an actual allergy is rare. Because of this, and the thickness of the e-liquid, it is very hard to find pure VG e-liquids. However, you can get e-liquids with a very high VG content. Alternatively, you can buy VG and flavour concentrates to mix your own e-liquid. If you do so, it is important to buy these from a reputable vape supplier.
Like PG, vegetable glycerin has been classified as “generally recognized as safe” by the FDA. It is not considered to be genotoxic or carcinogenic.
Unfortunately, there has not been much research on the inhalation of Vegetable Glycerine, and what research has been done is often clouded by tobacco politics. However, a 2008 study by Renne et al examined the impact on rats when they inhaled vegetable glycerine for 6 hours a day over two and thirteen week periods. The study did not detect toxic or carcinogenic changes, although irritation in the upper respiratory tract was noted.
A 2017 study by Phillips et al specifically looked at the impact of rats inhaling e-liquid ingredients over 90 days, and included mixtures of propylene glycol and vegetable glycerine. The study concluded that “ the PG/VG aerosols showed only very limited biological effects with no signs of toxicity.”
An older 1947 study by Robertson et al administered propylene glycol and triethylene glycol to monkeys and rats in the form of a vapour which was 50 - 700 times higher than the animals could absorb from air. The study concluded that:
“air containing these vapors in amounts up to the saturation point is completely harmless.”
Do note that overheating Vegetable Glcyerine can lead to thermal degradation, causing the release of toxic compounds like aldehydes and carbonyls. One study found that carbonyls were released during a simulated puff study using e-liquid which contained both VG and PG. However, a 2014 systematic review by Farsalinos and Polosa noted that the test was created under unrealistic conditions, only 3 carbonyls were detected and the levels of these were between 9 and 450 times lower than those found in tobacco emissions.
Vape devices have improved considerably since 2014, and all devices sold in the UK must undergo emissions testing to identify harmful substances. That said, to minimise risk it is important to follow manufacturer guidelines when using vape devices (especially with variable wattage devices), to change coils regularly and to discard any coil that has a slightly burnt taste.
VG is used in a vast array of applications. Below we have included some example uses:
Pharmaceuticals/Cosmetics
- Treat increased eye pressure such as glaucoma
- As a humectant and moisturiser to treat and prevent skin irritation.
- As a lubricant to help the application of products such as creams.
- As an ingredient in pharmaceutical drugs and common medicines.
- In toothpaste to prevent drying out.
Food industry
- To prevent ice-crystals forming in foods such as ice-cream and frozen yoghurt.
- As a thickener or sweetener.
- Found in many common foods including bakery, cereals and confectionary
Other
- In fog machines/stage smoke
- Candles
