April 23, 2024

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Is it safe to smoke e-cigarettes even if they are nicotine-free?

Is it safe to smoke e-cigarettes even if they are nicotine-free?

Is it safe to smoke e-cigarettes even if they are nicotine-free?

In Japan, heated tobacco products are popular, but in Western countries, e-cigarettes are more common. In Japan, nicotine-free e-cigarettes are sold, but is it safe to smoke them?

E-cigarettes are not common in Japan, but in countries like the West, especially among young people, there is an increasing number of e-cigarette smokers. 

The World Health Organization (WHO) and various governments are starting to regulate them. There are very few e-cigarette smokers in Japan, but that is because they do not contain nicotine.

E-cigarettes come in vaporizer-type products that heat the e-liquid electrically to create vapor, which is then inhaled. Overseas, there are e-liquids for e-cigarettes that use synthetically produced nicotine, not tobacco leaves.

Is it safe to smoke e-cigarettes even if they are nicotine-free?screenshot from Yahoo Japan

In Japan, e-cigarettes using nicotine e-liquid are not considered tobacco products under the Tobacco Business Law, and the Ministry of Finance does not allow the manufacture and sale of e-cigarettes using nicotine e-liquid. Also, in Japan, nicotine is considered a pharmaceutical under the Pharmaceutical Affairs Law, so the manufacture and sale of nicotine patches, nicotine gum, and nicotine e-liquids require approval, and devices that use nicotine e-liquid are treated as medical devices, requiring approval as well.

Importing nicotine e-liquid into Japan (including joint purchases) for sale to others or advertising is prohibited, and free exchanges are also illegal. Of course, selling e-cigarettes using nicotine e-liquid without approval is illegal as well.

However, in reality, imported products are sometimes sold as “Nikoriki” in vape shops and online. In Japan, there are no regulations on e-cigarette smoking, and it is not always clear whether e-cigarettes contain nicotine e-liquid just by looking at them.

It is also possible to mix your own flavors, and kits are sold for this purpose. Cases of illegal drugs being added to e-cigarettes have also begun to emerge, highlighting the potential risks of e-cigarettes.

Deaths from e-cigarettes: So, is it safe to use e-cigarettes without nicotine?

In the summer of 2019, nearly 100 deaths were reported in the United States due to e-cigarette smoking. This phenomenon is called EVALI (e-cigarette or Vaping Product Use Associated Lung Injury), and according to the CDC, it appears to be caused by smoking liquids containing cannabis ingredients (THC) or vitamin E acetate.

E-cigarettes have been considered to have fewer adverse health effects than traditional cigarettes. However, recent studies have begun to show adverse effects on cardiovascular function, respiratory function, and other health effects, including those on nicotine-free e-cigarettes.

It is natural to think that actively inhaling substances that are not meant to be inhaled regularly for long periods of time could have some adverse effects on respiratory and cardiovascular function.

According to an experiment conducted on non-smokers (10 people) who had never smoked e-cigarettes by a research group in the United States, acute exposure to e-cigarettes (10 puffs, with one puff being equivalent to one puff of cigarette smoke) regardless of the presence of nicotine, altered the transcriptome (RNA) of small airway epithelial cells (important for respiration at the end of the airways) (※1).

The state of small airway epithelium is related to the onset and death from smoking-related lung diseases, particularly COPD (chronic obstructive pulmonary disease). Changes in the transcriptome of small airway epithelial cells may evaluate the risk of such diseases, so smoking e-cigarettes may increase the risk of future COPD development.

According to an experiment conducted by a research group in Sweden on smokers (9 women and 6 men), regardless of the presence of nicotine, inhaling e-cigarettes for 30 minutes increased the proportion of exhaled nitric oxide, airway obstruction, and decreased lung capacity even 2 hours later, as well as decreased resonance with heart rate. The same research group suggests that chemicals other than nicotine may have a rapid adverse effect on lung function (※2).

It has been shown that long-term use of e-cigarettes adversely affects lung immune function and reduces resistance to infections such as influenza. Although there are various devices and liquids for e-cigarettes, they commonly contain propylene glycol and glycerol. These two substances are also found in heated tobacco products, but many researchers believe they have harmful effects on lung lipids.

Adverse effects of e-cigarettes on children

Switching from traditional cigarettes to e-cigarettes seems to improve conditions such as arteriosclerosis and heart rate to some extent. However, in cases of long-term smokers or heavy smokers, switching to e-cigarettes does not improve the condition of hardened blood vessels, regardless of the presence of nicotine (※4).

In experiments using pregnant mice, exposure to nicotine-free e-cigarettes was found to have adverse effects on both the mother and the fetus, including metabolic function and liver damage (※5). In another study, exposing pregnant mice to nicotine-free e-cigarettes resulted in prolonged and severe arterial vascular damage in their offspring until they grew up (※6).

E-liquid for e-cigarettes contains various flavor components (aromatic alcohols, menthol, vanillin, ethyl acetate, ethyl lactate, etc.) in addition to nicotine. These components adversely affect lung function. Experiments exposing lung function (gas exchange) artificially created to e-cigarette flavor components have shown pulmonary toxicity that significantly deteriorates lung function (※7).

Many e-cigarettes heat metal blades electrically to vaporize the liquid. Therefore, there is a risk of inhaling dissolved metal components. There are various devices, including disposable pods, but generally, they contain aluminum, nickel, lead, tin, etc., and this was particularly common in products that were closer to the flavor of traditional cigarettes.

However, when you quit smoking e-cigarettes, there are immediate health benefits. An experiment by a Belgian research group on smokers (30 men only) evaluated the effects of short-term smoking cessation in e-cigarette smokers. As a result, short-term e-cigarette smoking cessation for 5 days increased FEF (forced expiratory flow rate) by 25% and reduced airway resistance, leading to improved lung function (※9).

In summary, e-cigarettes, even if they do not contain nicotine, have adverse effects on respiratory and cardiovascular function, and these effects are also seen in mothers and children. It is clear that various substances in e-cigarettes, such as propylene glycol, glycerol, flavorings, metal components, etc., can have adverse health effects with long-term use.

Is it safe to smoke e-cigarettes even if they are nicotine-free?


1:Michelle R. Staudt, et al., “Altered lung biology of healthy never smokers following acute inhalation of E-cigarettes” Respiratory Research, Vol.19, article number 78, 14, May, 2018
2:Lukasz Antoniewicz, et al., “Acute Effects of Electronic Cigarette Inhalation on the Vasculature and the Conducting Airways” Cardiovascular Toxicology, Vol.19, 441-450, 8, April, 2019
3:Matthew C. Madison, et al., “Electronic cigarettes disrupt lung lipid homeostasis and innate immunity independent of nicotine” The Journal of Clinical Investigation, Vol.129(10), 4290–4304, 1, October, 2019
4:Jacob Geoge, et al., “Cardiovascular Effects of Switching From Tobacco Cigarettes to Electronic Cigarettes” Journal of the American College of Cardiology, Vol.74(25), 3112-3120, December, 2019
5:Garard Li, et al., “E-cigarettes damage the liver and alter nutrient metabolism in pregnant mice and their offspring” ANNALS OF THE NEW YORK ACADEMY OF SCIENCES, Vol.1475, issue1, 17, June, 2020
6:Eiman Aboaziza, et al., “Maternal electronic cigarette use during pregnancy affects long-term arterial function in offspring” Journal of Applied Physiology, Vol.134(1), 59-71, January, 2023
7:Ria A. Goros, et al., “Adverse Biophysical Impact of e-Cigarette Flavors on Pulmonary Surfactant” Environmental Science & Technology, doi.org/10.1021/acs.est.3c05896, 12, October, 2023
8:Angela Aherrera, et al., “Metal Concentrations in E-Cigarette Aerosol Samples: A Comparison by Device Type and Flavor” Environmental Health Perspectives, Vol.131(12), 127004, 4, December, 2023
9:Martin Chaumont, et al., “Differential Effects of E-Cigarette on Microvascular Endothelial Function, Arterial Stiffness and Oxidative Stress: A Randomized Crossover Trial” scientific reports, 8, Article number: 10378, 10, July, 2018

(source:internet, reference only)

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