Are electronic cigarettes safe?

e-juice 4.jpgWhat is in the e-liquid and vapour?

The e-liquid (or 'e-juice') typically contains nicotine and flavourings, dissolved in propylene glycol and vegetable glycerine. More than 7,700 flavourings are available, including tobacco, menthol, fruit and confectionary flavours. Non-nicotine solutions and unflavoured liquids are also available.

The aerosol contains:

  • Nicotine
  • Propylene glycol
  • Vegetable glycerine
  • Some toxic compounds which are created in the heating process or are contaminants. These chemicals are at very low levels and are unlikely to pose significant health risks.

As there is no combustion or burning, vapour does not contain carbon monoxide or tar and many of the other toxins which are responsible for most of the health effects of smoking. Also, the vast majority of the 7,000 chemicals in tobacco smoke are completely absent.

Nicotine is one of the main causes of addiction to smoking, but it otherwise has relatively minor health effects, except in pregnancy. Nicotine should also be avoided in adolescence as it may affect brain development. Nicotine does not cause cancer, heart disease or lung disease.

Are they safe?

Some of the most common side effects of using e-cigarettes include dry mouth, irritation of the throat and mouth and a mild cough. These symptoms are usually mild and settle on their own in a few days in most cases.

However, e-cigarettes are substantially safer than smoking and serious side effects are very rare. Independent reviews by Public Health England and the UK Royal College of Physicans have concluded that the risk of harm from long-term e-cigarette use is unlikely to be more than 5% of the risk of smoking tobacco.

Nicotine itself causes relatively few health effects at the doses used in vaping, except in pregnancy and (possibly) adolescents. It does not cause cancer, heart disease or lung disease. It is the other 7,000 chemicals in tobacco smoke that cause most of the harm from smoking.

There are low levels of some toxic chemicals in the vapour from e-cigarettes, generally less than 5% of the levels in smoking (in most cases <1%). These chemicals have not been associated with any serious risk.

The long-term effects of e-cigarette use are not known precisely at present, but based on studies so far, the level of risk is much less than smoking and this is unlikely to change significantly in the future.

E-cigarettes are less addictive than cigarettes. Nicotine is absorbed more slowly and it is easier to stop vaping than smoking.

Rare cases of explosions and fires caused by e-cigarettes have been reported. According to the US Fire Administration, most of the incidents were caused by using the wrong power adaptor. Many more fires are caused by traditional cigarettes. Click here for more advice on battery safety.

E-cigarettes should not be used by non-smokers.

What about the risk to bystanders?

The risk to bystanders from ‘passive vaping’ appears to be minimal. Negligible amounts of nicotine and other chemicals are released into the air when the vaper exhales, but this dissipates quickly, unlike cigarette smoke.

The PHE report concludes ‘electronic cigarette use releases negligible levels of nicotine into ambient air with no identified health risks to bystanders’. Another review found that 'the potential of any significant adverse effects on bystanders is minimal'.

Nevertheless, indoor vaping is best avoided around children, pregnant women and people with heart or lung disease.


1. Public Health England. E-cigarettes - an evidence update. August 2015

2. Royal College of Physicians. Nicotine without smoke: Tobacco harm reduction. 2016

3. Farsalinos KE. Safety evaluation and risk assessment of electronic cigarettes as tobacco cigarette substitutes - a systematic review. Ther Adv Drug Saf 2014


Last Modified: 07-10-2017