E-cigarette safety

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E-cigarettes are a relatively new product – they aren’t risk free and we don’t yet know their long-term impact. We strongly discourage people who haven’t smoked from using them.

However, there are misconceptions among a large proportion of the public that e-cigarettes are equally or more harmful than smoking[1] Research to date actually indicates that they are less harmful as they don’t contain tobacco or involve combustion.

Here you will find a summary of the current available information on the relative safety of e-cigarettes compared to tobacco.


[1] Action on smoking and health (ASH). Use of e-cigarettes among adults in Great Britain, 2019. 2019.

Smoking is the biggest preventable cause of cancer. Being smoke free can prevent at least 15 types of cancer including lung, bowel and pancreatic cancers.​

Evidence so far indicates that e-cigarettes are far less harmful than smoking as they don’t contain tobacco or involve combustion.[1,2] There is no smoke, tar or carbon monoxide, and studies looking at key toxicants have generally found much lower levels than in cigarettes. They do contain nicotine, which is addictive, but isn’t responsible for the major health harms from smoking.

The evidence so far points towards e-cigarettes being far closer to other nicotine replacement therapy (NRT) products than tobacco in terms of harm.[2] NRT has an established safety and effectiveness profile,[3] and although we don’t have definitive proof of long-term safety, evidence from people who have used these products for years shows no increase in their risk of cancer or cardiovascular disease.[4,5]

The existing research led both Public Health England (PHE) and the Royal College of Physicians (RCP) to release reports highlighting the relative safety of alternative nicotine products and e-cigarettes compared to smoking.[6,7] However, as e-cigarettes are a relatively new product, their long term health consequences are not known. They should be viewed as a tool for quitting smoking only and should never be used by people who haven't smoked.

Cancer Research UK has a joint positioning statement with many health organisations, outlining a shared agreement that e-cigarettes are significantly less harmful than smoking,[8] as well as a positioning statement with the Royal College of General Practitioners (RCGP).


[1] Burstyn I. Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks. BMC Public Health. 2014;14(1):18.

[2] Shahab L, Goniewicz ML, Blount BC, et al. Nicotine, carcinogen, and toxin exposure in long-term e-cigarette and nicotine replacement therapy users: a cross-sectional study. Ann Intern Med 2017;166(6):390-400.

[3] NHS Health Scotland. Brief interventions: key issues to raise re e-cigarettes and harm reduction. NHS Health Scotland; 2015.

[4] Murray RP, Connett JE, Zapawa LM. Does nicotine replacement therapy cause cancer? Evidence from the lung health study. Nicotine Tob Res. 2009;11(9):1076–82.

[5] Murray RP, Bailey WC, Daniels K, et al. Safety of nicotine polacrilex gum used by 3,094 participants in the Lung Health Study. Lung Health Study Research Group. Chest. 1996;109(2):438-45.

[6] McNeill A, Brose L, Calder R, et al. E-cigarettes : an evidence update. London: PHE; 2015.

[7] Royal College of Physicians (RCP). Nicotine without smoke. London: Tobacco Advisory Group of the RCP; 2016.

[8] Public Health England (PHE). E-cigarettes: a developing public health consensus. London: PHE; 2016.

Some traces of toxic chemicals have been found in some products, although generally in much lower levels than tobacco cigarettes.[1,2] A study on e-cigarette toxicity screened vapours from 12 brands of e-cigarettes for content of four groups of potentially toxic and carcinogenic compounds: volatile organic compounds (VOCs), tobacco-specific nitrosamines (TSNAs), carbonyls and heavy metals.[2] The paper clearly shows that other chemicals are present when using these e-cigarettes; however, the levels were 9-450 times lower than in tobacco smoke.[2]

In 2017 a landmark paper funded by Cancer Research UK demonstrated that in long-term e-cigarette users (who had been using their product for at least 6 months) many toxicants present in smokers’ urine were significantly lower in e-cigarette users. These included metabolites of the lung carcinogen NNK and a number of volatile organic compounds. This was only the case for those who switched entirely to e-cigarettes from tobacco. Levels in e-cigarette users were also comparable to those who were exclusively using other nicotine replacement therapies (NRTs).[3]



[1] Williams M, Villarreal A, Bozhilov K, et al. Metal and silicate particles including nanoparticles are present in electronic cigarette cartomizer fluid and aerosol. PLoS One 2013;8(3):e57987.

[2] Goniewicz ML, Knysak J, Gawron M, et al. Levels of selected carcinogens and toxicants in vapour from electronic cigarettes. Tob Control 2014;23:133-139.

[3] Shahab L, Goniewicz ML, Blount BC, et al. Nicotine, carcinogen, and toxin exposure in long-term e-cigarette and nicotine replacement therapy users: a cross-sectional study. Ann Intern Med 2017;166(6):390-400.

Fatal nicotine poisoning is extremely rare.[1]  Nicotine delivery via e-cigarettes poses little danger to adults. As with NRT, if people have more nicotine than they’re used to, they might feel a little nauseous or light-headed, both of which will pass quickly. If this happens, the person needs to reduce the level of nicotine in the e-liquid they’re buying, or use the e-cigarette less often.

In order to prevent accidental poisoning of children, e-cigarettes and e-liquid should be stored away safely, out of the reach of children, just as is the case with NRT products, household cleaning products and medicines.[1]



[1] National Centre for Smoking Cessation and Training (NCSCT). Electronic cigarettes: a briefing for stop smoking services. London: NCSCT; 2016. 

The toxicants in second hand tobacco smoke are responsible for thousands of deaths every year.[1] E-cigarettes do not use combustion and there is no side-stream vapour (i.e. the smoke from the lighted end of the cigarette), so the only source of second-hand vapour is that exhaled by the user. The evidence to date suggests toxicants may be present but at much lower levels in second-hand e-cigarette vapour than second-hand cigarette smoke and there is no convincing evidence of harm to bystanders so far.[2,3,4,5,6] Any harm to both users and bystanders from second-hand vapour is likely to be much lower than that of tobacco.



[1] Jamrozik K. Estimate of deaths attributable to passive smoking among UK adults: database analysis. BMJ 2005:330-812.

[2] Czogala J, Goniewicz ML, Fidelus B, et al. Secondhand exposure to vapors from electronic cigarettes. Nicotine Tob Res 2014;16(6):655-662.

[3] McAuley TR, Hopke PK, Zhao J, et al. Comparison of the effects of e-cigarette vapor and cigarette smoke on indoor air quality. Inhal Toxicol 2012;24(12):850-857.

[4] Ballbè M, Martínez-Sánchez JM, Sureda X, et al. Cigarettes vs. e-cigarettes: passive exposure at home measured by means of airborne marker and biomarkers. Environ Res 2014;135:76-80.

[5] Saffari A, Daher N, De Marco C, et al. Particulate metals and organic compounds from electronic and tobacco-containing cigarettes: comparison of emission rates and secondhand exposure. Environ Sci Process Impacts 2014;16(10):2259-2267.

[6] Hess IM, Lachireddy K, Capon A. A systematic review of the health risks from passive exposure to electronic cigarette vapour. Public Health Res Pract 2016;26(2):e2621617.

There are many different flavours of e-cigarettes, and the variety is one of the things that attracts some people to switching to e-cigarettes.

E-cigarette toxicity tests have looked at flavoured e-liquids, and demonstrated relative safety compared to smoking. However, it is important to note that because of the wide variety available, it is not possible to provide safety information for all types on the market.

Stopping smoking is one of the best things a woman and her partner can do to protect the health of their baby through pregnancy and beyond. If someone can’t stop using nicotine entirely, licensed NRT products can be safely used during pregnancy as the strength and quality of nicotine can be tightly controlled. They can increase the chances of quitting successfully, especially when combined with specialist help from Stop Smoking Services.[1,2]

The Smoking in Pregnancy Challenge Group has produced a short briefing to help health professionals respond to some of the most common questions about e-cigarette use during pregnancy. They advise that while licensed NRT products are the recommended option, if a pregnant woman has chosen to use an e-cigarette to quit, she should not be discouraged from doing so.[1,3]

All pregnant women who smoke should be referred to their local Stop Smoking Services for advice and support.



[1] Smoking in Pregnancy Challenge Group. Use of electronic cigarettes in pregnancy: a guide for midwives and other healthcare professionals. London: SIP; 2013.

[2] NHS Scotland. Health Scotland’s position on e-cigarette use in NHS Scotland. NHS Scotland; 2015.

[3] National Centre for Smoking Cessation and Training (NCSCT). Electronic cigarettes: a briefing for stop smoking services. London: NCSCT; 2016.

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