Safety & Effectiveness
Click the button below to read the top 20 scientific studies on the safety and effectiveness of e-cigarettes
Top 20 scientific studies
The hazard to health arising from long-term vapour inhalation from the e-cigarettes available today is unlikely to exceed 5% of the harm from smoking tobacco.
E-cigarettes appear to be effective when used by smokers as an aid to quitting smoking.
This is not surprising as most of the harm from smoking is due to the tar, carbon monoxide and 7,000 other toxic chemicals produced by burning tobacco. Vaporisers do not contain tobacco and there is no combustion or smoke.
Click here for more indepth findings from the UK Royal College of Physicians report in 2016.
According to Public Health England ,‘the constituents of cigarette smoke that harm health – including carcinogens – are either absent in e-cigarette vapour or, if present, they are mostly at levels much below 5% of smoking doses (mostly below 1% and far below safety limits for occupational exposure).
There was no evidence of potential for exposures of e-cigarette users to contaminants that are associated with risk to health at a level that would warrant attention if it were an involuntary workplace exposures. The vast majority of predicted exposures are less than 1% of TLV. Predicted exposures to acrolein and formaldehyde are typically less than 5% TLV. Considering exposure to the aerosol as a mixture of contaminants did not indicate that exceeding half of TLV for mixtures was plausible. Only exposures to the declared major ingredients -- propylene glycol and glycerin -- warrant attention because of precautionary nature of TLVs for exposures to hydrocarbons with no established toxicity
Nicotine does have some relatively minor effects on the cardiovascular system. It causes a temporary increase in the heart rate and blood pressure and may induce an irregular heartbeat (arrhythmia). Nicotine also increases the body’s resistance to the hormone insulin, leading to increased blood sugar (glucose) levels. However, these effects from nicotine are much less from vaping than they are from smoking tobacco.
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. Furthermore, the vapour consists of liquid droplets which evaporates almost immediately after exhalation, unlike cigarette smoke which persists in the air for 30-45 minutes.
(PHE) provided some compelling research that found e-cigarettes are saving thousands of lives each year. Not only did the report conclude that vaping poses only a small fraction of the risks of smoking and switching completely from smoking to vaping conveys substantial health benefits, but it found that “there have been no identified health risks of passive vaping to bystanders”.
Health benefits of switching to e-cigarettes - links to studies below
A small randomised controlled trial
showed that 34% of electronic cigarette users gave up smoking entirely vs 0% of the control.
of adult smokers making their first purchase at vape shops were followed up at 6 and 12 months and found 40.8% had quit smoking entirely.
Biochemically verified smoking cessation among a cross section of vape store customers confiremd that 66%
had quit smoking entirely.
Every year there is more growing evidence that vaping is helping smokers quit. The UK & US have both seen millions of people transition over.
Personal vaporisers are now the most popular quitting aid in the United Kingdom, the United States and the European Union. It was estimated that over 6 million people quit smoking with a vaporiser in the European Union in 2014. In the US there were 2.6 million former smokers who had switched completely to vaping in 2016, and 1.5 million in the UK in 2017.
Smoking rates in countries where e-cigarettes are widely available are falling faster than in Australia. It is very likely that e-cigarettes are a contributing factor to this rapid decline although it is not possible to prove cause and effect. However, in Australia where vaping is heavily restricted, the smoking rate has stalled for the last 3 years (2013-2016).
This table portrays smoking rates in countries where e-cigarettes are widely available are falling faster than in Australia.
E-liquid generally consists of nicotine and flavourings dissolved in propylene glycol (PG) and vegetable glycerine (VG).
Propylene glycol (PG)
Propylene glycol (propane-1,2 diol) is a clear, tasteless liquid found in almost all e-liquids. It is also used in a wide range of products such as foods, asthma inhalers, air disinfectants and food flavourings. Another common use is for making theatre fog in stage productions.
Along with nicotine, PG helps to create the familiar ‘throat hit’ that smokers are used to, which can help make the transition from smoking to vaping easier. PG also helps to carry the flavouring in the e-liquid.
PG is generally regarded as safe but there is limited experience with long term inhalation. Some people can find it irritating in the mouth or lungs and may need to choose e-liquids with lower PG levels. On the other hand, PG has antibacterial properties and may help to reduce infections.
PG is a ‘thin’ liquid and is drawn into the wick more efficiently when you take a puff.
Click here for more information about PG and VG.
Vegetable glycerine (VG)
The other ingredient in almost all e-liquids is vegetable glycerine (VG), a clear, sweet tasting liquid. VG is also widely used in pharmaceuticals (such as cough syrups, creams), toothpaste and foods. It is generally regarded as very safe although there is limited information on long-term inhalation.
The main function of VG is to produce a thicker, denser vapour with a smoother feel. The greater the percentage of VG in the liquid, the more vapour is produced.
VG is quite viscous liquid though and does not soak quickly into the wick.
Most e-liquids are based on a combination of PG and VG, expressed as a PG:VG ratio, such as 50:50, 60:40 or 70:30, depending on the percentages of each in the mix.
A good starting ratio is 50:50. People who want big clouds choose more VG. Higher levels of PG give a stronger ‘throat hit’. People who are sensitive to PG, may reduce their PG levels and increase the VG component. The ratio chosen is very much a matter of personal preference.
Nicotine is the main addictive chemical in tobacco smoke and most vapers use nicotine in their e-liquid to avoid smoking urges and withdrawal symptoms. It also contributes to the familiar ‘throat hit’ from vaping. Some users find nicotine-free e-liquid is effective as they are not nicotine-dependent but enjoy the hand-to-mouth vaping experience.
Nicotine in e-liquid is extracted from the tobacco leaf, just like the nicotine used in nicotine patches and gums etc. Although many companies now use pharmaceutical grade nicotine (medicine quality) it still may contain small amounts of contaminants from the tobacco plant. Some companies are now making synthetic non-tobacco nicotine, although it is expensive and not widely available.
Many users start with tobacco flavoured e-liquid which more closely resembles a smoking experience. However, over time, most progress to other flavourings such as mint, fruit, sweet, food and beverage flavours. Flavours are usually included in pre-mixed solutions.
Most of the flavouring chemicals are food flavourings and are safe to ingest, but less is known about their safety for inhalation. Some flavours could potentially cause harm from long-term vaping. However, any risk from flavouring chemicals is likely to be much less than from smoking.
Small amounts of chemicals and some toxins are produced by the thermal breakdown of PG, VG and flavourings when e-liquid is heated. These chemicals are present in the inhaled vapour in low quantities. Although some of these chemicals are potentially harmful, they are generally less than 1% of the concentrations in smoke.