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Clinical Studies


Dozens of studies on vaping are published every month, most focused on topics surrounding vaping and health. These range from clinical research on health risks to the analysis of e-liquid, vapor, and addiction. A few have received quite a bit of media attention, often because of alarming claims. Curiously, although no study has concluded vaping as entirely risk-free, by and large, the consensus is vaping is much safer than smoking. Beyond this agreement, there is no study establishing vaping as safe or a serious health risk. The best we can do is to continue our search for knowledge and remember if someone makes a claim... ask for their sources!

E-cigarettes help more smokers quit than patches and gum, study finds

Kate Kelland, 1/30/2019

E-cigarettes are almost twice as effective at helping smokers quit as nicotine replacement treatments like patches, lozenges, and gum, according to the results of a major clinical trial.

Dr. Farsalinos Discredits “Toxic Metal” Study For Being Misleading

Jimmy Hafrey, 2/28/2019

Researchers for the John Hopkins School of Public Health concluded that toxic metals such as arsenic, chromium, manganese, nickel, and lead were present after vaping… which constitutes a serious concern, as excessive levels of these substances have been linked to many types of cancer, immune conditions and cardiovascular issues. The only problem is these concentrations are far too low to be a cause for concern, according to Dr. Farsalinos. “The ‘significant amount’ of metals the authors reported they found were measured in ug/kg. In fact, they are so low that for some cases (chromium and lead) I calculated that you need to vape more than 100 ml per day in order to exceed the FDA limits for daily intake from inhalation medications. So when researchers calculations omit this fact, the results can appear drastically worse than they ought too.

Study: Smoking Relapse Less Likely Among Vapers

Notley, C., Ward, E., Dawkins, L., Holland, R., Jakes, S., 11/30/2018

The findings suggest that use of e-cigarettes not only helps people quit smoking, but also can help prevent long-term smoking relapse, according to the authors.

Health impact of E-cigarettes: a prospective 3.5-year study of regular daily users who have never smoked

Polosa, R., Cibella, F., Caponnetto, P., Maglia, M., Prosperini, U., Russo, C., & Tashkin, D., 11/17/2017​

In a small sample of young-adult never-smoking, daily EC users who were carefully followed for approximately 3½ years, we found no decrements in spirometric indices, development of respiratory symptoms, changes in markers of lung inflammation in exhaled air or findings of early lung damage on HRCT, when compared with a carefully matched group of never-smoking non-EC users. Even the heaviest EC users failed to exhibit any evidence of emerging lung injury as reflected in these physiologic, clinical or inflammatory measures. 

E-cigarettes emit very high formaldehyde levels only in conditions that are aversive to users: A replication study under verified realistic use conditions

Farsalinos KE1, Voudris V2, Spyrou A2, Poulas K, 11/2017

In 2015, a study identified 5–15-fold higher levels of formaldehyde emissions from an old-generation e-cigarette tested at 5.0 V compared to tobacco cigarettes. We set to replicate this study using the same e-cigarette equipment and e-liquid, while checking for the generation of dry puffs.  Conclusion: The high levels of formaldehyde emissions that were reported in a previous study were caused by unrealistic use conditions that create the unpleasant taste of dry puffs to e-cigarette users and are thus avoided.

Can Vaping Help Reverse COPD in Smokers?

Health effects in COPD smokers who switch to electronic cigarettes: a retrospective-prospective 3-year follow-up – Riccardo Polosa, Jaymin Bhagwanji Morjaria, Umberto Prosperini, Cristina Russo, Alfio Pennisi, Rosario Puleo, Massimo Caruso, Pasquale Caponnetto

Smoking is the largest single cause of chronic obstructive pulmonary disease (COPD), and unfortunately, many smokers with the condition remain unable to quit cigarettes, even after their diagnosis. The patients enrolled had mild-to-severe COPD as per the GOLD guidelines and were managed accordingly. In the 3-year period, a number of COPD patients in the EC study group down-staged from GOLD COPD Stages 4 and 3 to Stages 3 and 2, respectively. In contrast, there was virtually a lack of change in the COPD GOLD stages in the control group over the observation period. Scientists demonstrated that abstaining from smoking or substantially reducing cigarette consumption improves quality of life as well as respiratory outcomes in COPD and that these positive effects persist long-term. Ultimately, this three-year study showed that a group of COPD patients who smoked could reverse some of the harm caused by the disease by switching to e-cigarettes. The smokers who switched to vapor products showed improved overall health, and some COPD effects (like respiratory infections) were reduced.

New Study: Electronic Cigarettes Vapor Has NO Toxic Effect

VAPEFORM, 2/18/2016

in a recent study, scientists have found electronic cigarette vapor has NO toxic effect on the cells found in human lungs. Fresh research, funded by British American Tobacco (BAT), suggested inhaling nicotine vapor could be as safe as breathing air. Dr Marina Murphy, stated “by employing a combination of a smoking robot and a lab-based test using respiratory tissue, it was possible to demonstrate…. the e-cigarette aerosols used in this study have no [toxic] effect on human airway tissue.”

E-cigarette vapour does not induce DNA mutations linked to tobacco smoke exposures


E-cigarette vapour does not induce DNA mutations commonly observed with tobacco smoke exposures in lab-based tests.The Royal College of Physicians have said that the public can be reassured that e-cigarettes are much safer then smoking and that they should be widely promoted as an alternative to cigarettes, but called for more research to be done on the potential long term effects of using e-cigarettes.

1942 Study Uncovers Incredible Health Benefits of Inhaled Propylene Glycol

Dustin, 3/11/2015

Dr. Robertson concluded, “The propylene glycol itself was a potent germicide. One part of glycol in 2,000,000 parts of air would – within a few seconds – kill concentrations of air-suspended pneumococci, streptococci, and other bacteria numbering millions to the cubic foot.” It seems that PG could even help keep us healthy and protect against the spread of viruses like the flu.

Study finds nicotine safe, helps in Alzheimer's, Parkinson's

By Tom Valeo, 4/16/2014

"People won't smoke without nicotine in cigarettes, but they won't take nicotine by itself," said Newhouse, who has done extensive research into beneficial effects of nicotine on the brain. "Nicotine is not reinforcing enough. That's why FDA agreed nicotine could be sold over the counter. No one wants to take it because it's not pleasant enough by itself. And it's hard to get animals to self-administer nicotine the way they will with cocaine."

Mayo Clinic Reveals Results of A Ground Breaking New Ecig Experiment

Jimmy Hafrey, 2/5/2016

Recently, the Mayo Clinic released results from their latest experiment in smoking cessation. After noting that smokers face far higher risks of complications following surgery, researchers decided to offer patients “electronic nicotine delivery devices” both before and after their surgeries. Most remarkably, cigarette consumption was drastically reduced after patients had access to ecigarettes. “Average cigarette consumption decreased from 15.6 per person to 7.6 over the study period,” the study concluded. Ultimately, researchers said that ecig “use is feasible and well-accepted in surgical patients.”

A rapid method for the chromatographic analysis of volatile organic compounds in exhaled breath of tobacco cigarette and electronic cigarette smokers (2nd Hand Vapor)

Chromatogr A. 9/4/2013

The Spanish Council of Scientific Research published on Monday September 7th, 2015 in the Journal of Chromatography a study examining the chemical content of second hand vapor. Levels of several volatile organic compounds (VOC) were measured in indoor air, normal exhaled breath, smoke of tobacco cigarettes, exhaled breath of smokers after taking cigarette puffs, e-cigarette aerosol and exhaled breath of vapors after taking e-cigarette puffs. The results of the study indicate that e-cigarette aerosol alone contains less volatile organic compounds (VOC) than normal exhaled breath as well as normal indoor air.

Electronic cigarette use and harm reversal: emerging evidence in the lung

Riccardo Polosa, 3/15/2015

Electronic cigarettes (ECs) have been rapidly gaining ground on conventional cigarettes due to their efficiency in ceasing or reducing tobacco consumption, competitive prices, and the perception of them being a much less harmful smoking alternative. Acute investigations do not appear to support negative respiratory health outcomes in EC users and initial findings from long-term studies are supportive of a beneficial effect of EC use in relation to respiratory outcomes. The emerging evidence that EC use can reverse harm from tobacco smoking should be taken into consideration by regulatory authorities seeking to adopt proportional measures for the e-vapor category.

Nicotine, the Wonder Drug?

Dan Hurley, February 05, 2014, March 2014 Issue

This notorious stimulant may enhance learning and help treat Parkinson's, schizophrenia and other neurological diseases. Perhaps most surprising is that, in studies by Boyd and others, nicotine has not caused addiction or withdrawal when used to treat disease. These findings fly in the face of nicotine’s reputation as one of the most addictive substances known, but it’s a reputation built on myth.

Safety evaluation and risk assessment of electronic cigarettes as tobacco cigarette substitutes: a systematic review

Konstantinos E. Farsalinos, Riccardo Polosa, February 13, 2014

Currently available evidence indicates that electronic cigarettes are by far a less harmful alternative to smoking and significant health benefits are expected in smokers who switch from tobacco to electronic cigarettes.

Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks.

Burstyn, 1/9/2014

Professor Igor Burstyn of Drexel University School of Public Health studied e-liquids to determine if the chemicals in e-liquid could be dangerous. He refuted all the most widespread health concerns about e-liquids

Impact of Flavour Variability on Electronic Cigarette Use Experience: An Internet Survey

Int J Environ Res Public Health. 2013 Dec; 10(12): 7272–7282.Published online 2013 Dec 17. doi: 10.3390/ijerph10127272

The results of this survey of dedicated users indicate that flavours are marketed in order to satisfy vapers’ demand. They appear to contribute to both perceived pleasure and the effort to reduce cigarette consumption or quit smoking. Due to the fact that adoption of ECs by youngsters is currently minimal, it seems that implementing regulatory restrictions to flavours could cause harm to current vapers while no public health benefits would be observed in youngsters. Therefore, flavours variability should be maintained; any potential future risk for youngsters being attracted to ECs can be sufficiently minimized by strictly prohibiting EC sales in this population group.

Effects of electronic cigarette use on the elastic properties of the ascending aorta in healthy subjects: comparison with the effects of tobacco cigarettes

K. Farsalinos, D. Tsiapras, S. Kyrzopoulos, A. Spyrou, C. Stefopoulos, K. Tsimopoulou, G. Romagna, M. Tsakalou, V. Voudris, 12/2013

Significantly decreased elasticity and elevated stiffness of ascending aorta was observed after smoking, confirming previous studies. However, no adverse effects were observed after using the EC. Research on ECs should be intensified since they may be potentially useful in reducing the adverse vascular effects associated with smoking.

First Study to Examine E-Cigarette Gateway Hypothesis Can Find Only One Nonsmoker Who Initiated with E-Cigs and Went on to Smoke

Wagener, T, 10/31/2013

Dr. Ted Wagener from the University of Oklahoma Health Sciences Center studied the impact of e-cigarette use on 1,300 college students. He discovered that only one person that first used nicotine in the form of e-cigs went on to start smoking tobacco cigarettes. He concluded that e-cigs were not a gateway to tobacco use. Our public policies must be science-based. But when one draws pre-determined conclusions, rather than rely on the scientific evidence, this does not lead to evidence-based policies. My fear is that because of a strong pre-existing ideology against electronic cigarettes because they simulate the physical actions of smoking, tobacco control groups are drawing conclusions based on ideology rather than on science.

Acute impact of active and passive electronic cigarette smoking on serum cotinine and lung function

Flouris AD1, Chorti MS, Poulianiti KP, Jamurtas AZ, Kostikas K, Tzatzarakis MN, Wallace Hayes A, Tsatsakis AM, Koutedakis Y, 1/30/2013

Researchers compared first and second hand impacts of exposure to e-cigarette vapor to learn how it would impact respiratory function. The result was that secondhand exposure to tobacco smoke was more damaging to lung function than first hand exposure to vapor from e-cigarettes. They concluded that e-cigs cause no acute respiratory impact.

Comparison of the effects of e-cigarette vapor and cigarette smoke on indoor air quality.

Inhal Toxicol. 10/24/2012

Comparisons of pollutant concentrations were made between e-cigarette vapor and tobacco smoke samples.  Non-cancer risk analysis revealed "No Significant Risk" of harm to human health for vapor samples from e-liquids (A-D). In contrast, for tobacco smoke most findings markedly exceeded risk limits indicating a condition of "Significant Risk" of harm to human health. With regard to cancer risk analysis, no vapor sample from e-liquids A-D exceeded the risk limit for either children or adults.

Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of ecigarette users

Heavner, Dunworth, Bergen, Nissen, Phillips, 11/26/2009

Independent university researchers conducted a study to find out whether switching to e-cigs had any influence on health. They concluded that 91 percent of smokers that switched to electronic cigarettes had notably improved health. They also noted that 97 percent had reduced or completely eliminated chronic coughs.

Electronic cigarettes as a harm reduction strategy for tobacco control: A step forward or a repeat of past mistakes?

Zachary Cahn, Michael Siegel, 12/9/2010

We conclude that electronic cigarettes show tremendous promise in the fight against tobacco-related morbidity and mortality. By dramatically expanding the potential for harm reduction strategies to achieve substantial health gains, they may fundamentally alter the tobacco harm reduction debate.

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