The Effects and Safety of Propylene Glycol & Vegetable Glycerine

Should you be concerned?

25 June 2023 | Hannah Rubery

When it comes to vaping, you have probably heard that some of the key ingredients in vape juice are propylene glycol (PG) and vegetable glycerine (VG). While both are deemed safe for human consumption by organizations such as the US Food and Drug Administration (FDA), UK Medicines and Healthcare products Regulatory Agency (MHRA), and European Union (EU), there have been discussions and concerns about the use of these ingredients in vape products.

In this article, we discuss precisely what PG and VG are, their uses outside of vaping, the potential risks associated with them, any side effects that may be related to their use in E-Liquid, why people are concerned about PG and VG, and whether you should be concerned.

Just what is Propylene Glycol and Vegetable Glycerine?

Propylene glycol is a synthetic compound belonging to the alcohol family. It’s colourless, odourless and has a slightly sweet taste, and can be used as a humectant, preservative and solvent in various products ranging from food to personal care products. PG is also commonly found in smoke/fog machines used in theatres, nightclubs and other public venues.

Vegetable glycerine, on the other hand, is a colourless, odourless, sweet-tasting viscous liquid derived from vegetable oils or fats. It’s commonly used in foods and cosmetics as an emollient and thickening agent and also has humectant properties that help to retain moisture in the skin. It can also be found in many medicines as an additive and solvent.

Their uses outside of vaping

Propylene glycol is used widely in food processing, cosmetics, pharmaceuticals, and industrial products; the FDA also approves it for use as a direct food additive. Some common places you may find PG are packaged foods, beer, soft drinks, popcorn, bread and baked goods. PG acts as a moisture preserver to help products retain their moisture which is why you can find it used for things like marshmallows or coconut flakes. It's so commonly used that it can be found in some medicines, creams and balms, and hygiene products.

It can also be found in antifreeze which caused quite a stir when that first hit the news. The extremely harmful chemical Ethylene glycol found in antifreeze, is used alongside Propylene glycol to lower the freezing point of a water-based liquid. Sometimes there can be confusion between the two, but they are very different, especially as Ethylene glycol is highly toxic to humans.

Vegetable glycerine is also used widely in numerous industries including pharmaceuticals, foods, beverages and cosmetics. It’s a popular substitute for animal fats in many food products, as it’s plant-based and can often be used for vegan options. Outside of vaping, VG is used in food products as a food preserver and sweetener and retains moisture in food. Like PG, it can often be found in lozenges and cough medicines.

What are the risks of Propylene Glycol and Vegetable Glycerine?

The short answer is that there are no known long-term risks associated with PG or VG when used in vape juice. Studies have found that both propylene glycol and vegetable glycerine are generally considered to be non-toxic for human consumption.

Many articles have surfaced claiming Propylene Glycol causes heart issues, neurological issues, kidney problems and much more. What we do know is that the toxicity of PG is very low and has not been found to cause cancer, damage genes or interfere with fertility or reproduction. PG is partially broken down by the kidneys which is then turned into lactic acid, less than half of the absorbed PG is left unchanged. Those with kidney or liver issues, and pregnant women and children, should avoid PG in large amounts to avoid any potential issues.

Are there any side effects associated?

Side effects are highly individualised and depend on the person’s sensitivity and tolerance to PG and VG. The most common side effect reported is a sore throat, dry mouth, or feeling of irritation in the nose or eyes when vaped at higher temperatures. This can be avoided by vaping at lower temperatures which can reduce the amount of irritation caused by PG/VG.

Other side effects that may be associated with PG and VG include headaches, nausea, coughing, chest tightness or congestion. Again, these side effects depend on the individual and can be avoided by reducing vaping temperatures or switching to a different type of E-Liquid. It is possible, on rare occasions, that someone may have sensitivity or an allergic reaction to either chemical. Those that do should immediately stop using PG and VG-containing products and speak with a healthcare professional.

Why are people concerned about PG and VG?

Propylene Glycol and Vegetable Glycerine have been the cause of much controversy over the years due to their use in vape juice. Many people falsely believe that since PG is used in antifreeze, it must be extremely harmful when inhaled. This is simply not true and any potential risks associated with PG have been vastly exaggerated.

VG has also come under fire with the same concerns of lung irritation. Many of the studies surrounding VG and PG are often clouded by tobacco politics and scaremongering. More research should be conducted to confidently find long-term effects, but what we do know is that there is some potential for lung irritation to be caused, as is the same for many inhaled products. Any harm however is much less than that of cigarettes, but is still not completely harmless, which is why non-smokers should not take up vaping.

Should you be concerned about PG and VG?

The answer here is not without a caveat. There may be some potential risks associated with their use, however, these are much less than those caused by cigarettes. It is for this reason that it is not recommended for non-smokers to start vaping. Vaping is a tool designed for aiding smoking cessation in a much less harmful way. Vape products including disposables and E-Liquid still hold some harm, just much less than cigarettes, and should not be used by those who have never smoked.