Health effects of electronic cigarettes

Nicotine electronic cigarettes (“e-cigs” or “vapes”) can damage people's health, especially children's, but are far less harmful than smoking. Electronic cigarettes increase the risk of asthma and chronic obstructive pulmonary disease (COPD) compared to not using nicotine at all. Pregnant women vaping may increase the risk of their children suffering from asthma and COPD. Vaping is associated with heart failure, and can cause seizures. Unregulated or modified e-cigs or liquids may be more dangerous than those whose production is well-regulated. Misuse, accidents, and product malfunction issues increase risks such as nicotine poisoning, contact with liquid nicotine, and severe burns. Some of the most common but less serious adverse effects include abdominal pain, headache, blurry vision, throat and mouth irritation, vomiting, nausea, and coughing. People can become dependant on vapes. Nicotine is addictive and harmful to fetuses, children, and young people. However vaping while pregnant is less dangerous than smoking while pregnant. Passive e-cigarette vapor exposure may be harmful to children, but more studies are needed as of 2026.

Randomized controlled trials have provided "high-certainty" evidence that e-cigarettes containing nicotine are more effective than nicotine replacement therapy for discontinuing tobacco smoking, and moderate‐certainty evidence that they are more effective than e-cigarettes free of nicotine.

Harm reduction

When a person does not want to quit nicotine, harm reduction means striving to eliminate exposure to smoke by replacing it with vaping. E-cigarettes can reduce smokers' exposure to carcinogens and other toxic chemicals found in tobacco. Tobacco harm reduction has been a controversial area of tobacco control. Health advocates have been slow to support a harm reduction method out of concern that tobacco companies cannot be trusted to sell products that will lower the risks associated with tobacco use. A large number of smokers want to reduce harm from smoking by instead using e-cigarettes. Quitting smoking is the most effective strategy for tobacco harm reduction. Tobacco smoke contains 100 known carcinogens and 900 potentially cancer-causing chemicals, but e-cigarette vapor contains fewer potential carcinogens than tobacco smoke. A 2025 review of 39 studies found "no significant incident or prevalent risk" of cancer from vaping. Due to their similarity to traditional cigarettes, e-cigarettes could play a valuable role in tobacco harm reduction. The public health community remains divided concerning the appropriateness of endorsing a device whose safety and efficacy for smoking cessation remain unclear. Overall, the available evidence supports the cautionary implementation of harm reduction interventions aimed at promoting e-cigarettes as attractive and competitive alternatives to cigarette smoking, while taking measures to protect vulnerable groups and individuals. An evidence review commissioned by England's Office for Health Improvement and Disparities (OHID) concluded that, in the short and medium term, vaping poses a small fraction of the risks of smoking, while noting that vaping is not risk-free for people who have never smoked. Dual use may be an increased risk to a smoker who continues to use even a minimal amount of traditional cigarettes, rather than quitting. Because of the convenience of e-cigarettes, it may further increase the risk of addiction. Evidence to substantiate the potential of vaping to lower tobacco-related death and disease is unknown. E-cigarettes could have an influential role in tobacco harm reduction. One study's authors warned against the potential harm of excessive regulation and advised health professionals to consider advising smokers who are reluctant to quit by other methods to switch to e-cigarettes as a safer alternative to smoking.

Smoking cessation E-cigarettes can help people quit smoking , but only about one in ten quit. Limited evidence suggests that e-cigarettes likely do help people to stop smoking when used in clinical settings. However, more smokers become dual users than succeed in complete abstinence. Outside clinical settings, vaping does not greatly change the odds of quitting smoking. The public health community is divided over the use of these devices to reduce or prevent smoking. As of 2017, they were not approved by the US Centers for Disease Control and Prevention (CDC) as a smoking cessation product, and in 2020, they became regulated as a tobacco product, despite not containing tobacco. However, a 2019 study reported that 10% of participants given nicotine via gum, mouth spray, patches, etc., quit smoking, while 18% of those given vaping kits quit. Among study participants still smoking, e-cigarette users smoked less. A 2021 review by Public Health England (PHE) reported vaping to be around 95% less harmful than smoking. E-cigarettes are estimated to have preserved 677,000 life–years in the US alone from 2011 to 2019. A small number of studies have looked at whether using e-cigarettes reduces the number of cigarettes smokers consume. It is unclear whether e-cigarettes are only helpful for particular types of smokers. Vaping with nicotine may reduce tobacco use among daily smokers. Whether vaping is effective for quitting smoking may depend on whether it was used as part of an effort to quit. Evidence suggests smokers are more frequently able to completely quit smoking using tank devices compared to cigalikes, which may be due to their more efficient nicotine delivery. One study supports the claim that smokers are more likely to use e-cigarettes as a nicotine replacement product to aid in smoking cessation than other pharmaceutical products. There is low-quality evidence that vaping assists smokers to quit smoking in the long-term compared with nicotine-free vaping. Tentative evidence indicates that health warnings on vaping products may influence users to give up vaping. There is robust evidence that vaping is not effective for quitting smoking among adolescents. In view of the shortage of evidence, vaping is not recommend for cancer patients, although for all patients vaping is likely less dangerous than smoking cigarettes. The effectiveness of vaping for quitting smoking among vulnerable groups is uncertain.

Safety

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