How harmless is the e-cigarette?

The title is intentional. I could have asked how harmful e-cigarettes are. But when talking about a grain of sand, you would rather ask how small it is rather than how large. This is related to relations.

Relations are important. They allow us to properly assess things. If I want to describe how large my new swimming pool is, I can mention its square footage. A clear unit. But no one can really visualize that. It’s better if I compare it to something everyone can imagine. Like a tennis court. My paddling pool is half the size of a tennis court. Now, the image is clear in one’s mind.

Of course, this only works with something that’s in the same league. Comparing it to Lake Constance, for instance, would be a poor choice. Even though almost everyone knows it. If I mention that my pool is roughly 0.00006% the size of Lake Constance, I would only get blank stares.

So, what does my swimming pool, which I don’t even have, have to do with the e-cigarette? As I said, it’s all about relations. This is particularly true for the harmfulness of the e-cigarette. Because harm can’t be defined as simply as the area of a paddling pool. There’s no unit for it. I am compelled to use a comparison. And for the e-cigarette, two possible comparisons present themselves: breathing air and cigarette smoke.

A comparison is not simple.

Especially the opponents of the e-cigarette use pure breathing air as a reference. Not without ulterior motives. Because they refer to an ideal concept of “breathing air.” A construct. Something in the direction of fresh mountain air. But nothing can naturally compare to that. In comparison, even burps are chemical weapons.
Besides other flawed thinking, the cloud enemies deliberately ignore one thing: there is no such thing as pure breathing air. It’s not a standardized term. And most people don’t live in the mountains. However, there is a huge difference between breathing in a small mountain village or in a big city. In fact, it can be more harmful to breathe in a city than to take a drag from an e-cigarette. But we’ll get to that.

First, let’s deal with the second meaningful reference size, cigarette smoke. The e-cigarette was invented as an alternative to the cigarette. So, in the beginning, it was only about one thing: getting people to quit smoking with the e-cigarette. Logically, almost all vapers are former smokers.
For this reason, it is absolutely legitimate to compare the vapor of e-cigarettes with cigarette smoke. Just to give smokers an idea of what they’re getting into with the e-cigarette. After all, the only thing that matters to them is whether they benefit from switching.
But there is also a problem here. Because hardly any pleasure product is as harmful as cigarettes. Many scientists believe that half of all smokers die from the effects of smoking. Smoking can be fatal. No matter what I compare with cigarettes, this deadly aspect always resonates. A little bit deadly is still deadly for most people. Especially if it’s called “cigarette” in any way.
The reality, however, is that the cigarette is like Lake Constance and the e-cigarette is my swimming pool. We lack something like a tennis court for comparison. We only have the construct of breathing air or the deadly cigarette. The funny thing is that with the breathing air, we are much closer to the e-cigarette than to tobacco smoke. Why, we’ll get to that now.

At least 95% less harmful.

The British Department of Health (Public Health England) conducted a risk assessment of the e-cigarette for the first time in 2015. It based its findings on the work of the London Royal College of Physicians, one of the most prestigious institutes worldwide. The conclusion was that e-cigarettes are only a fraction as harmful as cigarettes. At least 95% less harmful. This assessment was last updated and confirmed in 2022(1). The remaining 5% risk is not just about direct harm. It also includes issues such as potential addiction or social exclusion. So it includes a lot of “safety buffer”.
A meta-study from the USA(2) came to an even clearer result. The authors looked at many different studies that examined the pollutant content of e-cigarette vapor. From these results, the risks for a variety of diseases were calculated. The study concludes that the e-cigarette has 97% lower potential harm than cigarettes, thus confirming the assessment of the British scientists.

The pollutants are missing.

It is therefore undeniable that vaping is far less harmful than smoking. And it’s not surprising when you take a closer look at the vapor. A French study(3) did this in 2021. The French scientists found, compared to cigarette smoke, 99.79% less carbonyl compounds (e.g., formaldehyde) in e-cigarette vapor, and 99.42% fewer PAHs (polycyclic aromatic hydrocarbons such as naphthalene). All in all, over 99% fewer pollutants.
But it’s not just that far fewer pollutants were found. The amounts found were so small that they are practically irrelevant to health.

Now it should be clear why the e-cigarette has more in common with normal breathing air than with tobacco smoke. And that’s why city air can be unhealthier than vaping. By the way, over the course of a day, humans exhale more formaldehyde and acetaldehyde as metabolic products than they typically inhale from an e-cigarette during the same period. Human breath is also not fresh mountain air.

Metals are also rare.

Then we have the metals. They are often pointed out in the media. They are supposed to be terribly unhealthy. Opponents of the e-cigarette and some politicians keep bringing this up.
And yes, metals were indeed found(4). However, they appeared in an extremely low concentration in the vapor. How low becomes clear when we use the limit value for inhalative drugs as a yardstick for potential risk. To reach this limit, a vaper would have to vape liters of liquid(5). For lead, the limit is exceeded after 135ml of liquid per day. For aluminum, you’d need one and a half tons of liquid. Nickel looks the worst. But even here, a vaper would need about 17ml to reach the limit.
So, yes, metals can be present in the vapor of an e-cigarette. But the amounts are too small to be relevant to health.

An infinitesimally small risk.

The fact that the e-cigarette produces so few pollutants is naturally also reflected in the risk for various typical smoking diseases. Several studies(6)(7) have shown that the use of e-cigarettes does not increase the risk of cardiovascular diseases. This is also consistent with the finding that the condition of blood vessels significantly improves just one month after switching from smoking to vaping(8). E-cigarette users show values similar to those found in non-smokers and non-vapers.
The risk of high blood pressure is also not increased by the use of e-cigarettes(9).
In a study from the USA(10), no negative effects of vaping on blood vessels or inflammatory processes in the body were observed in young and healthy adults.

The situation is similar for lung diseases. Vaping does not increase the risk of COPD(11)(12). One of the most common and severe diseases that can affect smokers. And even more. In smokers who already had COPD, the symptoms did not deteriorate further after switching to the e-cigarette. In some cases, they even improved somewhat.

Most deaths caused by smoking are probably due to cancer, primarily lung cancer. A Scottish study(13) therefore examined how much the e-cigarette influences the personal risk of developing cancer in one’s lifetime. The authors concluded that vapers, compared to smokers, have a 99.6% lower cancer risk. This remaining risk of 0.4% is so low that it is clinically irrelevant and therefore negligible.

The perpetual harping on long-term studies.

Now there is a very special argument against the e-cigarette. That is the lack of long-term studies. Without them, a statement on long-term consequences would be impossible. But that’s simply nonsense.
Firstly, there’s hardly a long-term study for anything in life, not even for medications. And that works out quite well. Especially for vaping such a study is redundant. We know exactly what’s in the vapor and how it affects the body. That’s enough to reliably estimate the risk. Even for the future.
Secondly, the question arises, how long should a long-term study last? Ten years? Twenty years? Fifty years? Or even longer? Someone is always unsatisfied. And in the meantime? Let the smokers die.
What should such a study even look like? Encourage non-smokers to vape and watch for a few years to see what happens? This would likely not be approved by any ethics committee. Such a study simply cannot exist. And everyone who uses this argument knows that. It’s a pure straw man argument. Without an expiration date.
Is it 100% certain that no severe negative consequences will emerge in the future? No. But only because nothing is 100% certain. With anything. But we can cope with that.
The e-cigarette has been around for almost 20 years now. It’s being closely monitored by the scientific community. So far, there’s no cause for concern.

The basic ingredients are harmless.

There are also many voices that already describe the basic ingredients of e-cigarette liquids as problematic. They say that propylene glycol (1,2-propanediol) and glycerin (glycerol) themselves are already pollutants. This is simply and plainly wrong.
The ECHA (European Chemicals Agency) decided in 2016 not to classify propylene glycol as an irritant to the respiratory tract(14). The agency saw no basis for this classification.
In fact, studies on rats and dogs(15)(16) show that both basic ingredients of liquids are unproblematic for inhalation.
Now one might be unsettled by the German guideline values for propylene glycol in indoor air(17). But only until you know how they came about. The calculation of the guideline values actually relied on only one single study. In this study, rats started to have nosebleeds after inhaling extremely large amounts of propylene glycol mist for an extremely long time. All other studies were ignored, where no negative reactions of the test animals were observed.
Whatever the motivation was to set such utterly ridiculous guideline values. But they don’t make sense at all. They are even lower than the guideline value for formaldehyde.

Many opponents of vaping are also bothered by the flavors. Eating is okay. But vaping too? Shouldn’t be a problem. There is no evidence to suggest that they act differently in the lungs than in the stomach or intestines. For example, an Austrian study found no evidence that flavors damage blood vessels(18).
Of course, there are also flavors that can be problematic. Both in food and in vaping. One controversial example is diacetyl. It is suspected of causing so-called popcorn lung (bronchiolitis obliterans). However, this has not yet been proven. Nevertheless, its use, and that of other potentially problematic flavors like coumarin, is prohibited in e-cigarettes in Germany.

“Passive vapers” can be reassured.

From all this, it’s clear that so-called “passive vapor” can’t be a big deal. There’s nothing that any non-smoker or non-vaper should be afraid of. This has been confirmed by studies.
The authors of a Bavarian study(19) try to somehow construct a risk. But in the end, the study clearly shows that “passive vaping” is harmless. Propylene glycol and glycerin were, of course, found in the air. But they are not pollutants. The extremely low amounts of nicotine are completely harmless. Formaldehyde was only detected once in homeopathic amounts in several measurements. And they found 4,400 times less benzyl alcohol than would be permissible according to the workplace limit value.
In a Spanish study(20), even fewer VOCs (volatile organic compounds) were found in the mist of an e-cigarette than in human breath(21). A Dutch study(22) also confirmed the absence of relevant amounts of pollutants.

It goes without saying that vapers should be considerate of their surroundings. But there is no scientific basis for a vaping ban in public places. “Passive vaping” is harmless.
Otherwise, by the way, we would also have to ban disco fog. Because that’s exactly what comes out of the e-cigarette: disco fog with flavor.

Not everything you enjoy doing is necessarily an addiction.

It’s clear that smoking can be addictive. You consume something even though it noticeably harms you and can kill you. This meets the main criteria for the definition of dependency.
I don’t want to go into detail about what exactly makes smoking addictive. That would be too much. The factors range from habit to tobacco. Nicotine is just one component among many. Even on a substance level, as research now knows(23). The addictive potential of nicotine, on the other hand, seems to be very low without tobacco(24).
Therefore, it’s not surprising that e-cigarette users show significantly fewer signs of addiction than smokers(25)(26).

Saving lives made easy.

At the same time, there’s hardly anything else that makes it as easy to quit smoking as with the e-cigarette. The chance of quitting smoking is 50 to 100% higher with the e-cigarette than with nicotine replacement therapies such as gums, sprays, or patches(27)(28).
Moreover, the risk of relapse is very low(29). Those who have made the switch can rightly call themselves non-smokers.
Of course, not everyone manages to make the complete switch immediately. Many use tobacco and e-cigarettes, at least for a while, in parallel. This is called dual use. For most, it’s just a stopover to exclusive vaping. But even as a dual user, you’re likely doing less harm than if you only smoked(30).

It’s about the children.

The last major argument against e-cigarettes that media, activists, and politicians like to bring up is our children and adolescents. Their protection allegedly justifies radical regulations of the e-cigarette, including flavor bans. This is meant to make vaping less appealing to adolescents. However, this line of argument fundamentally contains a huge flaw. We don’t have to make anything unappealing for young people. We simply need to ensure that youth protection measures are effective. That’s the purpose of youth protection. Adults should do adult things, and measures should be in place to ensure young people don’t.

If we regulate everything to the point where it’s uninteresting for both adolescents and adults, we might as well do away with it all.

But let’s take a step back. I want to pose a question that is rarely asked. Yet, it’s the crucial one: Does youth protection for e-cigarettes even make sense?

There are three main arguments for youth protection:

1. E-cigarettes harm adolescents.
2. E-cigarettes get adolescents addicted to nicotine.
3. Because of e-cigarettes, adolescents start smoking.

I’ve already extensively discussed the issue of harm. Do we really need to protect young people from disco fog with flavor?! Some soft drinks are provably more harmful than vaping. In Germany, in the presence of their parents or legal guardians, children are allowed to consume alcoholic beverages like beer or wine from the age of 14. One sip is already more harmful than a month of vaping. There’s also no evidence suggesting that nicotine negatively affects adolescents’ development. The only studies claiming this were conducted on mice. But humans are not mice.(31) And the effects observed in mice weren’t seen in humans.

But for many, addiction is an even bigger concern than harm. However, some may be surprised to learn that nicotine isn’t the “addictive substance” it’s often portrayed to be. Many scientists now view nicotine in a different light due to e-cigarettes. They equate nicotine’s effects and addiction potential to that of caffeine.(32) This is reflected in the youth as well. In the US in 2019, only 2.9% of young people who had used e-cigarettes showed signs of addiction.(33) If adolescents had never smoked before, their risk of developing an addiction appeared especially low.

Beyond harm and addiction, there’s one more knockdown argument that vaping opponents often use: the so-called gateway effect. This theory suggests that adolescents will eventually transition from vaping to smoking, implying that vaping is merely a precursor to smoking. This gateway hypothesis exists not only for e-cigarettes but was also previously suggested for alcohol and cannabis. However, this theory quickly falls apart when faced with reality. It’s simply not provable. If a young person transitions from an e-cigarette to a cigarette, it doesn’t conclusively prove anything. It might be possible that vaping led them to consider smoking. But it’s equally plausible that they would have started smoking regardless of e-cigarettes. Many factors come into play. Some people are more prone to risk-taking and drug use due to genetics, upbringing, or social environment. All we can determine is a correlation, not causality. And in many studies(34)(35)(36), it was demonstrated that there’s no evidence of this gateway effect. Even more, some studies suggest that e-cigarettes might even prevent some adolescents from starting to smoke(37)(38).

In the end, the arguments of e-cigarette youth protection proponents don’t hold much weight. At best, they are weak conjectures. On the other hand, it’s evident that not only adults but also adolescent smokers can transition away from cigarettes through vaping. Moreover, e-cigarettes might even save some young people from a lifetime of smoking. It might have started with the intention to protect the youth. But I believe that now it’s about something entirely different. Smoking has become socially stigmatized. And vaping an e-cigarette resembles this behavior. Many conflate the two, even though they are fundamentally different. Today, it’s no longer about protection from harm. It’s about a behavior. It’s about preventing young people from doing something that looks like smoking. This approach sacrifices the best method for smoking cessation available to both young and adult smokers. The best chance to save their health and perhaps even their lives.

Perhaps we should at least have an honest discussion about a compromise. If smoking is legally allowed from the age of 18, the age limit for vaping should at least be lowered to 16. If someone wants to experiment with inhaling clouds, they should do it with a relatively harmless method. Because one thing is for sure: There will always be people who want to inhale clouds or consume nicotine. It’s better to do it in a way that doesn’t destroy them or end their lives.

Studies on Demand

The matter seems clear. And it shouldn’t surprise anyone who understands the difference between smoke and mist. Nevertheless, the impression keeps arising that things aren’t as clear as they seem. After all, media, opponents of e-cigarettes, and occasionally politicians come up with different studies. In these studies, e-cigarettes suddenly don’t look so harmless. How can that be?

Mainly, it’s due to three reasons: lack of context, unrealistic tests, and incorrect or misinterpreted data.

There are many examples of missing context. For instance, in a study we already discussed. The one where metals were found in the mist of e-cigarettes. Without context, this information could be easily blown out of proportion. After all, something as unpleasant as lead was involved. The media loves this. But when you put the numbers in the right context, the whole situation looks very different. The amounts found are extremely small. One would have to vape liters of liquid daily for it to become harmful. We have already seen the same with other substances like formaldehyde. Yes, it’s present. For the media and activists, this information is enough. The rest apparently no longer interests anyone: there is less formaldehyde than in a person’s breath.

Then we have the classic: self-created reality. Either the vaporizers are unrealistically overheated, producing any desired pollutant. How often this has happened is shown by a French meta-study(39). Or cells are drowned in vast amounts of liquid. And then, of course, there’s media-effective shock. Because the cells didn’t respond well to it. No surprise there. In this way, I could declare ketchup a highly toxic mixture. Torturing mice is also popular. Mice are abused with such unrealistically large amounts of nicotine that they collapse from stress. All the results of these studies should be thrown in the trash. Instead, they end up on the desks of headline-hungry editorial offices.

Lastly, there’s the lowest tier of scientific endeavors. Studies where data is manipulated to fit a certain narrative. The most famous example of this might be Stanton A. Glantz’s heart attack study(40). Here, Glantz wanted to find a causal link between the use of e-cigarettes and the risk of heart attack. However, he made a rookie mistake. He also counted heart attacks that occurred before the individual even started vaping. In my opinion, such a mistake is not made accidentally. It’s too obvious. Consequently, there was a lot of criticism from the scientific community. Therefore, the “Journal of the American Heart Association” had to retract this disastrous study(41). Of course, the study had already been whipped through all media outlets. But no editorial office cared in the end that the study was withdrawn.

A little Conclusion

The facts are on the table. At least when you omit all the scientific nonsense. The few possible risks of e-cigarettes are purely hypothetical. To date, there’s no evidence of any significant harm. After nearly 20 years.

Of course, vaping hasn’t been around for a hundred years. Maybe in 50 years, all vapers will suddenly lose their manhood. Women included. But that’s just not realistic. We don’t need a hundred years to make a serious estimate of how safe vaping is.
The uncertainty regarding certain flavors is manageable. Flavors that cause harm should be banned. Based on clear scientific facts. That’s how it works everywhere. And it works.

The topic of banning vaping in public places shouldn’t even be a subject. There’s nothing anyone needs protection from. There’s no factual basis for prohibitive laws. Protecting from being bothered by disco fog with flavor isn’t the job of lawmakers.

Youth protection must be rethought for e-cigarettes. Without ideological blinders. The benefits of the e-cigarette far outweigh the possible risks. Most smokers started in their youth. That’s exactly where e-cigarettes should come in. Before the damage is done.

Vaping isn’t smoking. Vapers are non-smokers. The e-cigarette isn’t an accomplice to smoking; it’s its biggest enemy. Yet the best friend of smokers. It’s the greatest opportunity in the fight against smoking and for smokers. Because the problem isn’t behavior. The problem is the harm. We need to understand that. Only then can we seize this opportunity. We’re talking about millions of lives.

(Zur deutschen Version.)

(1) Public Health England: Nicotine vaping in England: 2022 evidence update summary
(2) Rachel Murkett et al.: Nicotine products relative risk assessment: an updated systematic review and meta-analysis
(3) Romain Dusautoir et al.: Comparison of the chemical composition of aerosols from heated tobacco products, electronic cigarettes and tobacco cigarettes and their toxic impacts on the human bronchial epithelial BEAS-2B cells
(4) Pablo Olmedo et al.: Metal Concentrations in e-Cigarette Liquid and Aerosol Samples: The Contribution of Metallic Coils
(5) Konstantinos E. Farsalinos et al.: Metal emissions from e-cigarettes: a risk assessment analysis of a recently-published study
(6) Jonathan B. Berlowitz et al.: E-Cigarette Use and Risk of Cardiovascular Disease: A Longitudinal Analysis of the PATH Study (2013–2019)
(7) Konstantinos E. Farsalinos et al.: Is e-cigarette use associated with coronary heart disease and myocardial infarction? Insights from the 2016 and 2017 National Health Interview Surveys
(8) Jacob George et al.: Cardiovascular Effects of Switching From Tobacco Cigarettes to Electronic Cigarettes
(9) Steven Cook et al.: Time-varying association between cigarette and ENDS use on incident hypertension among US adults: a prospective longitudinal study
(10) Ellen Boakye et al.: Examining the association of habitual e-cigarette use with inflammation and endothelial dysfunction in young adults: The VAPORS-Endothelial function study
(11) Laura M. Paulin et al.: Association of tobacco product use with chronic obstructive pulmonary disease (COPD) prevalence and incidence in Waves 1 through 5 (2013-2019) of the Population Assessment of Tobacco and Health (PATH) Study
(12) Steven F. Cook et al.: Cigarettes, ENDS Use, and Chronic Obstructive Pulmonary Disease Incidence: A Prospective Longitudinal Study
(13) William E. Stephens: Comparing the cancer potencies of emissions from vapourised nicotine products including e-cigarettes with those of tobacco smoke
(14) ECHA: Annex to a news alert ECHA/NA/16/37
(15) Blaine Phillips et al.: 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
(16) Michael S. Werley: Non-clinical safety and pharmacokinetic evaluations of propylene glycol aerosol in Sprague-Dawley rats and Beagle dogs
(17) Umweltbundesamt: Richtwert für Propan-1,2-diol (Propylenglykol) in der Innenraumluft
(18) Gerald Wölkart et al.: Effects of flavoring compounds used in electronic cigarette refill liquids on endothelial and vascular function
(19) Wolfgang Schober et al.: Expositionsstudie zur Passivrauchbelastung durch elektrische Zigaretten (E-Zigaretten)
(20) Ester Marco et al.: A rapid method for the chromatographic analysis of volatile organic compounds in exhaled breath of tobacco cigarette and electronic cigarette smokers
(21) Konstantinos E. Farsalinos: New study proves there is no second-hand vaping: e-cigarette aerosol contains less volatile compounds than normal exhaled breath
(22) Wouter F. Visser et al.: The Health Risks of Electronic Cigarette Use to Bystanders
(23) Christophe Lanteri et al.: Inhibition of Monoamine Oxidases Desensitizes 5-HT1A Autoreceptors and Allows Nicotine to Induce a Neurochemical and Behavioral Sensitization
(24) Karl Fagerström: Dependence on tobacco and nicotine
(25) Saul Shiffman et al.: Dependence on e-cigarettes and cigarettes in a cross-sectional study of US adults
(26) Jessica Yingst et al.: Changes in Nicotine Dependence Among Smokers Using Electronic Cigarettes to Reduce Cigarette Smoking in a Randomized Controlled Trial
(27) Jamie Hartmann-Boyce et al.: Electronic cigarettes for smoking cessation (Cochrane)
(28) Jeremy Y. Levett et al.: Efficacy and Safety of E-Cigarette Use for Smoking Cessation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
(29) Ping Du et al.: Changes in E-Cigarette Use Behaviors and Dependence in Long-term E-Cigarette Users
(30) Jamie Hartmann-Boyce et al.: Biomarkers of potential harm in people switching from smoking tobacco to exclusive e-cigarette use, dual use or abstinence: secondary analysis of Cochrane systematic review of trials of e-cigarettes for smoking cessation
(31) Junhee Seok et al.: Genomic responses in mouse models poorly mimic human inflammatory diseases
(32) Royal Society for Public Health: Nicotine “no more harmful to health than caffeine”
(33) Martin Jarvis et al.: Epidemic of youth nicotine addiction? What does the National Youth Tobacco Survey 2017-2019 reveal about high school e-cigarette use in the USA?
(34) Sandra Chyderiotis et al.: Does e-cigarette experimentation increase the transition to daily smoking among young ever-smokers in France?
(35) Natalie Walker et al.: Use of e-cigarettes and smoked tobacco in youth aged 14–15 years in New Zealand: findings from repeated cross-sectional studies (2014–19)
(36) Ruoyan Sun et al.: Is Adolescent E-Cigarette Use Associated With Subsequent Smoking? A New Look
(37) Dr. Lion Shahab et al.: Association of initial e-cigarette and other tobacco product use with subsequent cigarette smoking in adolescents: a cross-sectional, matched control study
(38) Natasha A. Sokol et al.: High School Seniors Who Used E-Cigarettes May Have Otherwise Been Cigarette Smokers: Evidence From Monitoring the Future (United States, 2009-2018)
(39) Sebastian Soulet et al.: Critical Review of the Recent Literature on Organic Byproducts in E-Cigarette Aerosol Emissions
(40) Stanton A. Glantz et al.: Electronic Cigarette Use and Myocardial Infarction Among Adults in the US Population Assessment of Tobacco and Health
(41) Journal of the American Heart Association: Retraction to: Electronic Cigarette Use and Myocardial Infarction Among Adults in the US Population Assessment of Tobacco and Health