Vape Ingredients: What is Vape Juice Made Of? Is It Bad For You?

by Rhys Callender on September 30, 2021

This is a question that I’ve seen asked repeatedly, both across social media and internet forums as well as from curious bystanders on the street, many of which have already formed a negative, and factually incorrect opinion surrounding the safety of and efficacy of vaping and e-liquids.

An e-liquid, or ‘vape juice’ can be broken down into three primary ingredients, Vegetable Glycerine, Propylene Glycol, and natural and/or artificial flavourings. Let’s go through each of these one by one, discuss what they are, what they are used widely used for, and the safety of each of these ingredients.

Vegetable Glycerine is the first and primary ingredient of e-liquid, and will comprise anywhere from 50% - 90% or greater of the overall volume of any given e-liquid. Vegetable Glycerine is a thick, colourless and odorless liquid which has a slightly sweet taste. It is extracted from plant sources such as palm, soybean, and rapespeed. It is non-toxic, and is used widely throughout various industries. Some common uses for vegetable glycerine include as a thickening agent, sweetener, moisturiser, lubricant, and is readily found in various food products, soaps, shampoos and skin care products and medicines, to name a few.

Vegetable Glycerine is used in e-liquid for three primary reasons, its low vaporisation point, which allows it to be vaporised at low temperatures, creating the ‘smoke’ like effect seen when using a vape, it’s viscosity, which prevents the overall liquid from being too thin and creating issues with leaking from the devices, and finally that it is both non-toxic and chemically inert.

Propylene Glycol is the second most abundant ingredient by volume, comprising anywhere from 5% up to 50% of any given e-liquid. Propylene Glycol is another colourless liquid, which has a faint odour and can be described as having a slightly bitter taste. It is highly refined and purified product derived from hydrocarbon sources, which like vegetable glycerine is widely used in various different applications ranging from industrial manufacturing, to food products such as ice cream, soft drink and food flavourings. It is also proven to be a potent bactericide, and has been used as an ingredient in air purifiers and hospital ventilation systems. However it’s most common and well known use is as a pharmaceutical solvent, which in layman’s terms is the ‘carrier’ substance used for delivering medications orally, topically, intravenously or via inhalation, the same property that makes it an essential component of e-liquid.

These solvent properties, combined with the fact it has been shown to be and deemed as safe for human consumption, allow its use as a solvent within e-liquids, allowing both flavourings and nicotine to ‘bond’ to its molecules when vaporised, therefore allowing these components to be vaporised and inhaled. Without Propylene Glycol, these components would, for the most part, not vaporise, instead separating from the Vegetable Glycerine and burning on the atomisers heating element. 

A common misconception surrounding Propylene Glycol is that it is the primary ingredient in antifreeze, which is of course a highly toxic substance. This is untrue, however it is easy to see how this misconception came to be. Dipropylene Glycol is in fact the ingredient that is found in antifreeze, and whilst this is a closely related to Propylene Glycol, and also has a very low toxicity, it is a separate compound entirely.

The final ingredient, excluding nicotine which may or may not be added, are the flavourings.
Firstly it is important to note that food flavourings and e-liquid flavourings are not the same, and are not interchangeable for two important factors, the first being the solvent used. Food based flavourings use various types of oils as a base, due to their fantastic solvent properties, their low cost and of course due to the fact they are safe for human consumption. However, while oils are safe to ingest, they are not safe to inhale. Therefore, in order to create flavourings specific for use in e-liquids, a different solvent had to be used, Propylene Glycol.

The second factor is the various chemical compounds which actually comprise the flavouring, which can range up to dozens of individual compounds within the one flavouring. Whilst the vast majority of these are the same between both food and e-liquid flavourings, there are certain compounds present in food flavourings which are deemed unsafe for inhalation. An example of one of these compounds is Cinnamaldehyde, the chemical found in cinnamon which gives it it’s flavour. Cinnamaldehyde is a skin irritant, and whilst ingesting it is deemed as safe and does not cause any noticeable toxicity, inhaling it can cause lung irritation.

Probably the most well-known and misunderstood compound surrounding the vaping safety debate is Diacetyl, better known as the compound responsible for ‘Popcorn Lung’. Diacetyl is a compound which imparts a ‘buttery’ flavour. The actual disease is known as Obliterative Bronchiolitis, but garnered the name ‘Popcorn Lung’ after 8 employees working in a popcorn factory in Jasper, Missouri during the 1990s developed the disease. It was shown that the disease was caused by the inhalation of large quantities of diacetyl, which was used as a flavouring agent in the popcorn.

Fast forward ten years, and a study was released in which various e-liquids were analysed and traces of diacetyl were detected, following which we began to see hundreds of sensationalised articles within the media claiming that vaping caused ‘Popcorn Lung’.

What these articles didn’t take into account is that the workers at the popcorn factory were inhaling vast massive quantities of powdered diacetyl over years or even decades before the disease developed, at concentrations tens of thousands of times greater than those found in the e-liquids tested. To put it into perspective, a traditional cigarette has been shown to contain up between 80 and 100 times greater concentration of diacetyl than that found in e-cigarettes, yet a smoker has never been diagnosed with the disease.

Whilst it is ideal for e-liquids to contain no diacetyl, which the vast majority no longer do as manufacturers of flavourings for e-liquids have since found alternatives or removed the compound entirely from their products, it is relatively safe to say that the past e-liquids which did contain the compound, contained it in such low concentrations it is highly unlikely it would have ever led to any adverse effects.
In conclusion, with the massive growth of the vaping industry over the past decade, there are dozens of flavouring manufacturers who create their products specifically for use in e-liquids, and have spent significant time and money researching, developing and testing these flavours to ensure their safety.

The final component is of course nicotine, which is an entirely optional component, not all e-liquids contain nicotine, and in fact anything sold in Australia legally should not. It is the users responsibility to safely and legally source nicotine and add it to the e-liquid themselves for use as a quitting aid. Another common misconception is that nicotine gives you cancer, this is incorrect. Nicotine is simply the primary addictive compound found in tobacco, however it is not carcinogenic, and has a very similar effect on your body to that of caffeine.

So there you have it, an outline of each of the ingredients found in e-liquid, their uses, and their toxicity, or lack thereof. To answer the question, ‘is vaping bad for you?’ I believe it is safe to say from taking into consideration all of the information listed above, accompanied by the extensive testing conducted by the scientific community over the past two decades, that there is a very low chance that vaping will have any negative impact on your health.

Of course, there is always a chance that something has been missed, and I would not recommend anybody who is not a smoker to take up vaping, it is safe to say that vaping is a very safe and highly effective method to quit smoking, and by all current standards is deemed to be a minimum of 95% less harmful than smoking traditional cigarettes.