E-cigarettes, heated tobacco and smokeless tobacco products

E-cigarettes are battery-operated devices that usually contain nicotine. They enable users to breathe in vapour that delivers nicotine without burning tobacco. They are sometimes referred to as Electronic Nicotine Delivery Systems (ENDS) and this term includes devices such as vapes, e-hookahs, e-pipes and e-cigars. These devices work by heating a liquid so that it turns into a vapour for the user to inhale, or ‘vape’. Although the vapour may look like steam, it does not contain any water. The liquid is made from chemicals such as propylene glycol and/or glycerine, and it can have different flavours and different amounts of nicotine, which the user can select.

Research into the safety of e-cigarettes is complicated as there are differences between devices and the way people use the devices. Also e-cigarettes are constantly changing with new devices emerging; there are currently hundreds of brands and thousands of flavours available. As the products are relatively new, there are no long-term studies yet looking at the impact of e-cigarettes across someone’s lifetime. Diseases caused by smoking can take 30-50 years to develop and e-cigarettes have only been in widespread use since the early 2000s. This means that their long-term safety is not yet known.

Most e-cigarettes contain nicotine at varying levels, depending on the device. Studies have found evidence showing that nicotine is harmful for health, affecting brain development up to the age of 25. It is also an addictive substance and people begin to crave it the more it is used.

There are many studies that have looked into the short-term impact of e-cigarettes on health. These studies have found toxic and cancer-causing chemicals in the vapour of e-cigarettes. Although the levels of some of these substances are lower than in traditional cigarettes, there is still concern that they can be harmful. A review in 2019 found that even non-nicotine e-cigarette liquids contain 243 unique chemicals, including known poisons and substances that are prohibited.

There is evidence that cells in the body that are exposed to e-cigarette vapour become damaged and stop working. There is also evidence of a link between inhaling the vapour and an increased chance of inflammation and infections in the lungs. Inflammation in the lungs can cause difficulty breathing, shortness of breath and a dry cough.

Studies have shown that healthy e-cigarette users have irritation in the airways and signs of bronchitis. Large surveys have revealed that e-cigarette users more frequently report lung symptoms than people who have never used them.

An illness known as vaping-related lung injury began to be seen in 2019. Doctors in the USA reported cases of people with symptoms including shortness of breath, fever, cough, vomiting, diarrhoea, headache, dizziness and chest pain. In some cases, these patients became very ill and were hospitalised and in the most extreme cases, a small number of patients died. An extensive review in 2023 provided strong evidence that e-cigarette use could cause short-term lung injury, poisoning, burns, seizures and other symptoms in the lungs, particularly in young people.

Almost all independent research has revealed some negative health effects of e-cigarettes, and existing evidence indicates that this damage will have lasting effects and lead to the development of diseases.

It is not clear whether the vapour from an e-cigarette user can have a harmful effect on other people close by. This is known as second-hand exposure. While it is highly likely that the harm caused by second-hand exposure to e-cigarettes is less than second-hand exposure to traditional cigarettes, the limited research available suggests there may be some risk, especially to vulnerable people such as the elderly, people with lung disease or pregnant women. In addition to risk of exposure, there is also a risk of harm from devices exploding or spontaneously catching fire. Most experts believe there is harm linked to the use of e-cigarettes, but as no long-term data exists on the development of disease across a lifetime, it is not possible to conclude how harmful e-cigarettes are at this stage.

E-cigarettes are often used by smokers who are trying to quit. However, no e-cigarette brand has been approved as an aid to quit smoking. There are some studies that have shown that e-cigarettes can be used as a quitting aid, but there is a lack of evidence showing whether these work as well as established methods, such as nicotine patches and gum. Research suggests that most adults buy e-cigarettes to quit smoking, but many of them end up using both e-cigarettes and other tobacco products.

Currently, a few countries are considering whether to offer e-cigarettes as part of a treatment plan to quit smoking, in a similar way to traditional quitting methods. However, over 40 countries have banned the sale of e-cigarettes.

Traditional quitting methods, such as nicotine patches and gum, are usually offered by a pharmacy where a pharmacist can provide advice and the user may also be referred to psychological services for support fighting their addiction. These quitting methods are regulated and have controlled levels of nicotine. On the other hand, e-cigarettes can be purchased in shops on the high street and users will not usually access any other therapies to help them to quit. The levels of nicotine vary considerably and they are not regulated by health agencies.

There is evidence that the use of e-cigarettes has led to children and young adults taking up smoking, as e-cigarette users are more likely to try tobacco products, increasing the number of people needing to quit.

Heated tobacco products, or ‘Heat-not-burn’ products, are electronic devices that, unlike e-cigarettes, contain tobacco. The tobacco is heated to a high temperature, but it is not set alight. The products do not create the usual cigarette smoke but a vapour that the user breathes in. This contains nicotine, additives and is often flavoured. The levels of nicotine are highly variable between different brands.

Tobacco is toxic and contains toxins that are capable of causing cancer in all forms. The World Health Organization considers that all forms of tobacco use are harmful, including e-cigarettes, heat-not-burn products and smokeless tobacco.

There is currently no evidence showing that these products are any less harmful than traditional cigarettes. In fact, harmful chemicals were found in heated tobacco products in higher amounts than in traditional cigarette smoke. There is some evidence of chemicals in heated tobacco products that are not present in traditional cigarettes, and which could be toxic and harmful. Studies in both animals and humans have suggested the products are linked to increased heart rate and blood pressure after use and can cause harm to the heart and lungs. There is also some evidence that the toxins found in the vapour can cause cancer. Studies have also shown no improvement in lung function or inflammation in the lungs in smokers who switched to heated tobacco. There is currently insufficient evidence on whether second-hand exposure is harmful.

There is no evidence to support claims made by heated tobacco manufacturers that smokers often switch from traditional cigarettes to exclusive use of heated tobacco products.

Smokeless tobacco products include chewing tobacco and snus, which is placed between your lip and your gum. The composition of smokeless tobacco products varies, but many have been found to include cancer-causing chemicals. Research has linked the use of smokeless tobacco to cancer, stroke and mouth and heart diseases. Evidence of the risk of cancer due to the use of snus is inconclusive.

Nicotine pouches are another type of smokeless product used under the lip, in a similar way to snus, but they do not contain tobacco. Instead, they contain nicotine powder, salts, flavourings, and sweeteners. At the time of writing in February 2024, they are not subject to the same regulations that other tobacco products are. They can be freely marketed without any health warnings.

There is not yet enough evidence regarding the longer-term health risks of these products. Early research has highlighted alarmingly high nicotine contents in these products, raising concerns about the impact on oral health. Additionally, cancer-causing substances have also been found in these pouches, which may contribute to tumour growth.

This page has given a summary of the evidence available products that claim to reduce the amount of harm for users compared with traditional cigarettes.

‘Tobacco harm reduction’ refers to an approach to reduce the harm caused by cigarette smoking, when completely giving up smoking may feel unachievable for some people. There is some debate among policymakers whether this strategy should be implemented to help people stop smoking. Some experts believe that reducing the amount of toxins in the body is the most important thing, even if some still remain. Others believe that we should not be recommending the use of products that have any damaging effects, even at reduced levels.

There is not yet enough evidence to say definitively whether there is a lower risk from these products compared to normal cigarettes.

As organisations working in lung health, the advice from the European Respiratory Society (ERS) and European Lung Foundation (ELF), is as follows: “The human lungs are created to breathe clean air, not toxins and carcinogens, and the human body is not meant to be dependent on addictive drugs. ERS and ELF cannot recommend any product that is damaging to the lungs and human health. Even if there is some value in recommending them to individuals who have not seen success with using methods of quitting smoking, there is a wider risk to the population. This is particularly the case for young people who are taking up e-cigarettes without having smoked before.”

Isabel Saraiva, former chair of the European Lung Foundation, who sadly passed away in 2024, previously commented: “As an ex-smoker, I understand that it is tempting for people, who think that it will be easier to stop smoking by substituting cigarettes with e-cigarettes. If they had been available when I was trying to stop, I would not have been able to break my addiction to nicotine. Lungs are made for clean air and clean air only. I believe e-cigarettes are dangerous, particularly for children. It is my view that the only possible way to quit smoking for good is with professional help from healthcare workers.”

“We have an array of effective and evidenced-based tobacco control measures which, when implemented appropriately, can help smokers quit; millions of them have in recent decades. Harm reduction approaches maintain nicotine addiction, which is something most smokers despise and they also pose the risk of exposing young people who don’t smoke to harmful products”.

This factsheet was produced in March 2020 and updated in February 2024

For further information, read the European Respiratory Society’s position statement on novel products and harm reduction: https://erj.ersjournals.com/content/early/2024/02/01/13993003.01808-2023