The Safety Of E-Liquid, What We Know Now

E-cigarettes have been touted as the newer safer alternative to traditional smoking. Understandably so, this has piqued the interest of those looking to kick the harmful habit of tobacco smoking. No one argues that e-cigarettes are safer, but if you follow news in the e-cigarette world, you have probably at least heard it said that there is not enough long-term research to verify whether e-cigarette vapor is truly safe or not.

With electronic cigarettes being such relatively new products on the marketplace there simply has not been the time to observe what long-term effects, if any, could even exist from long-term e-cigarette use. While many, in fact you could probably say all, experts will agree that e-cigarettes are far safer than regular cigarettes, the truth is science is yet to be able to verify what long term effects e-cigarette use, or more specifically, what the inhalation of e-liquid vapor, can do to a human.

E-Liquid is the substance that is heated to make the vapor in an electronic cigarette. Even as integral it is to the e-cigarette, e-liquid is truly a simple compound, made up of only a few ingredients that have been around for many years. By dissecting each component you find in e-liquid you can discover what the long-term effects of exposure might be, even though e-cigarettes, haven’t been on the market for even a decade yet.

History of E-Cigs

When Hon Lik, a Chinese pharmacist, began toiling with the idea of the modern e-cigarette, he did so with improved health and harm reduction in mind. He was a heavy smoker himself for years and his father had died of lung cancer, so his motivations were clear. In 2007 the new devices hit the market, and it wasn’t long before they were off and running. In 2014 the e-cigarette market grossed 2.5 billion dollars in sales and all signs point to the market only continuing to grow.

E-cigarettes are a fairly simple device, instead of releasing harmful smoke, they use a heating element, or atomizer to turn a special liquid into a “vapor” that the user inhales. The special liquid is the e-liquid which is the conduit for the nicotine to be delivered to the users’ system.

As electronic e-cigarettes grow in popularity, concerns about their health effects and how the e-liquid effects the user has become a topic of concern. In fact, recently, Public Health England came out in support of e-cigarettes, claiming that they are 95% less harmful than traditional smokes, and should be considered potential tools in cessation strategies. However safer, the question still remains about the true long term effect of e-cigarette use and the inhalation of vaporized e-liquid.

The Ingredients in E-Liquid

E-Liquid is an extremely simple combination of ingredients containing usually only four ingredients: water, nicotine, propylene glycol (PG) and flavoring. Not all e-liquids use propylene glycol, some use vegetable glycerin (VG), or in some cases, they will use a combination of both PG and VG, depending on the type of vapor the user is looking to inhale. Each ingredient used has several other applications in the consumer world, so we will explore each ingredient separately, to see if we can gather more information on the potential long-term effects of inhaling these ingredients, and as a result have a clearer picture of how the long-term effects of e-cigarettes may affect users who chose to vape.

Effects of Nicotine

Everyone knows how dangerous inhaling smoke is; which is the primary way that users administer nicotine to their system. That is why it is very hard to say how dangerous nicotine actually is. That is why there are studies that exist that have tried to answer this very question.

We all know that nicotine is dangerous in the sense of how addictive it is, this is what keeps smokers hooked to something that is so bad for them.  However, health researchers aren’t so sure that there is any real health danger beyond that. A study from 1996 confirmed this theory in a study conducted using laboratory rats, and administering nicotine to them in a pure inhalation form (It would be impossible to find studies on humans, due to the addictive nature of the substance human trials would be unethical). After thorough trials, the researchers concluded that: “our study does not indicate any harmful effect of nicotine when given in its pure form by inhalation.”

“We need to de-demonize nicotine,” said Ann McNeill, a professor of tobacco addiction at King’s College London, to Scientific American. McNeill is a familiar voice in the quit smoking community, who has been involved in several studies involving e-cigarettes. She has dedicated her career researching the different ways to help people quit smoking. Nicotine, she believes, can be an effective tool for cessation, and while addictive, it still may be a much less harmful substance than people tend to realize.

Nicotine also may even have some health benefits. Those who smoke or chew often reported a greater sense of concentration and it may be this very aspect of nicotine that could help users, rather than harm them. Studies have even suggested that nicotine not only helps prevents Alzheimer’s disease, but can also improve brain function in those already suffering from dementia.

Effects of Propylene Glycol

Propylene glycol (PG) is a synthetic liquid substance that is essentially odorless and tasteless. The Food and Drug Administration (FDA) has classified propylene glycol as an additive that is “generally recognized as safe” for use in food. It is also used for its absorbent qualities and as a solvent for flavors and food coloring. Propylene glycol is also used to create artificial smoke or fog used in fire-fighting training and in theatrical productions. Propylene glycol is clear, colorless, slightly syrupy and can be heated or to produce vapor. Propylene glycol is practically odorless and tasteless. The CDC, in their summary definition of the substance, state: “Propylene glycol is generally considered to be a safe chemical.”

Interestingly enough, there have been questions about the inhalation of propylene glycol for at least the last 70 years, understandably, since initially it was administered in hospitals as an addition to breathing treatments. Its uses, however, are widespread and you can find PG in everything from ice cream to anti-freeze. PG is just one ingredient, and on its own, its risk seems to be minimal if not non-existent. Going back to early studies conducted back in the 1940s, researchers seem to show that when inhaled, there is little to no harmful effect.  The following study in 1978 confirmed the same thing; that PG does not seem to be dangerous when orally inhaled. What they did find in the 1940 study, however, was that PG may also be a powerful deterrent against pneumonia, influenza, and other respiratory diseases when it is vaporized and inhaled.

 Effects of Vegetable Glycerin

There is much less information on the effects of VG, especially when you are looking into the danger of inhalation. Unlike PG, which has been used in breathing treatments, there has been little application in the inhalation sense. VG is often simply used instead of PG, for users concerned about the more “chemical” make-up of the latter. In addition, users report a different kind of vapor, what would be described as a stronger throat hit, something some electronic cigarette users simply prefer.

What we do know about VG, is it is a relatively safe substance. Also known as glycerol, VG is a clear and odorless liquid that is made from plant oils, typically palm, soy, or coconut oil. Vegetable glycerin has many uses but you will most often find it in cosmetic products, lotions, and herbal tinctures. VG is not only topically safe to your skin and body but is also safe to consume, since glycerin is produced in many types of fruits and vegetables, dairy products, and more.

Glycerol is one of the most benign organic liquids known to man. That is why it is used in so many amazing products. The SIDS initial assessment profile of PG confirms its safety in a variety of applications and also states that it has low toxicity levels for consumption, topical contact, and inhalation.

Since vegetable glycerin is regarded to be such a safe substance, less research is conducted to determine its safety, it is classified as of low importance for more research of study. With the advent of its use in e-cigarette liquid this feeling may change, however, it will still be a while before research presented on the long-term effects could be obtained. When they are, however, the likelihood of VG presenting any harmful effects seems minimal at best.

Effects of Flavoring

Flavoring is the largest variable in the e-liquid ingredient base. The word “flavoring” is sometimes all that is used in an ingredient description list, leaving a lot of room for questions. Flavorings, while they are generally approved by the FDA for consumption, aren’t necessarily tested for their safety in the terms of inhalation. Does that mean that flavorings are unsafe? Well not exactly, but it could open the door for some concerns.

Firstly, there are a few items that are consumed in our regular diet, are not healthy for you when inhaled. A good example of this is flour. Flour dust has been known to cause symptoms of asthma, chronic bronchitis and changes in your overall lung function.

In addition, there are well-known examples where inhaled flavoring can be potentially dangerous for your health. The most popular case of this is the used of the flavoring diacetyl, which is popular especially in butter flavoring. There wasn’t really even any understanding of how inhaling this was dangerous, when consuming it orally had appeared to present no trouble at all. Nonetheless, many factory workers began to experience health problems and lung disease in response to inhaling the flavoring substance through the course of their workday. What this created was something that came to be called “popcorn lung” and was a huge wake-up call to factory standards and manufacturing regulations. However, there is a large amount that we do not know about what inhaling already FDA approved substances will do, especially since testing them for inhalation has never been a need or a concern.

Now there is nothing even close to diacetyl in e-liquid, and even if there was the actual amount would be minuscule. It’s important to note that cigarettes themselves often contain flavor adding chemicals, generally to a much higher percentage than e-cigarettes do. The amount of flavoring in e-cigarette liquid is extremely small, a majority of the time measuring between 1% and 2% of the whole make-up of the e-liquid itself. In comparison, a cigarette contains about 8.5%, meaning four times as much chemical flavoring is present in cigarettes, and sometimes even more, in comparison to the e-version.

Even at such small levels, it is certainly worthy of more consideration and research to understand what can happen, especially to someone who becomes a long term user of e-cigarettes. Conjectures can be made, but there is still so much that we will simply have to wait for find out as far as long term inhalation effects. There isn’t a blanket answer that can be given about what flavorings really can do when inhaled, considering that hundreds, actually thousands, of different chemical flavoring agents are available for use in the e-cigarette and e-liquid world. Flavors are one of the main selling points of e-cigarettes, offering not only flavors that mimic the usual tobacco taste, but also exotic and appetizing sounding flavors from fruits concoctions to delicious desserts. To make these flavors one really must delve into the ingredients and flavorings to get a genuine flavor. Many e-liquid manufacturers have also begun using natural extracts, from fruits for instance, that help ease the question about what the “flavoring” actually is.


No one can claim to know everything about the safety of e-cigarettes and their e-liquids, despite the fact that many on both sides of the e-cigarette debate claim to. History has shown us that even when we think we know it all, we are usually wrong, if not just slightly misguided. To keep it in perspective, it was only just a little over 500 years ago the most brilliant minds on the planet believed the earth was flat, and those years are just a drop in the bucket in our human history. Remember, it was years after cigarettes were on the market before people realized the damage they had done. People for hundreds and hundreds of years before that were smoking tobacco unaware of the extent of its side effects.

The world has come a long way and these days technology and information is delivered to us by 160 character spoonfuls and at lightning speeds. When we want answers, we want them quick and we want them now, but the truth is sometimes you just have to wait to find out what is going to happen. We can use the tools with which we are given to help us decipher the most likely conclusions and outcomes; therefore using real scientific evidence to back up the conclusions.

Upon investigation, it appears as though all the ingredients in e-cigarettes on their own are fairly benign, as far as contributing to the overall harmful effect on the health of a user. When you combine the ingredients, the assumption is easily made that the resulting concoction will be just as harmless as the ingredients separately. There really is no way to say for certain that e-liquid is safe for use for the long haul. Until long term studies about the use of e-cigarettes become available these separate studies about the ingredients in and of themselves, may be the best clue to ease the worries about e-liquid for those looking to replace their old smokes with the new electronic ones.