Electronic cigarettes, also known as e-cigarettes, are battery-powered devices with liquid-filled cartridges that, when heated, create an inhalable mist. The liquid is flavoured to taste like tobacco, menthol or other more exotic flavours – such as various fruits, mint or chocolate – and may or may not contain nicotine.

Supporters argue that replacing regular cigarettes with e-cigarettes is a better way for people to get their nicotine. Where smoke from combustible cigarettes contains 4000 different chemicals, including more than 60 carcinogens, proponents claim e-cigarettes are healthier as they contain fewer toxins. Furthermore, second-hand smoke, which affects smokers and non-smokers alike, is negligible and likely safer.

Detractors, however, argue they could undermine efforts to de-normalise tobacco use. After decades of working to stigmatise smoking – with a high degree of success – health authorities are concerned these cigarette-like devices will once again make smoking 'cool'. There's also concern that they could entice children to start smoking, especially with kid-friendly flavours such as strawberry and bubblegum on offer.

Are they safe to use?

The safety of e-cigarettes is questionable. Nicotine is a highly toxic chemical, and overseas studies have found the amount of nicotine delivered in e-cigarettes may be more or less than the amount stated. Leakages are also a risk, and nicotine absorbed through the skin can make people very sick and even kill them. While nicotine replacement therapy (NRT) products, such as gum and patches, have been rigorously assessed for efficacy and safety, no assessment of electronic cigarettes has been undertaken.

Another issue identified by the World Health Organisation (WHO), in a 2014 report on the marketing and use of e-cigarettes, is the variability among products (hardware and liquids) and hence in the toxicity of their contents and emissions.

Their relatively recent entry into the market, along with the lengthy lag time for onset of many diseases of interest, such as cancer, means that conclusive evidence about the association of e-cigarettes with such diseases will not be available for years. Possibly even decades.

However, the WHO report acknowledges, "it is very likely that average [e-cigarette] use produces lower exposures to toxicants that combustible products," although the amount of risk reduction is currently unknown.

Do they help smokers quit?

As to whether they help people quit smoking, some studies have found they're as effective as conventional NRT products or even more so, while some have not. Nevertheless, there are plenty of anecdotal reports of people using e-cigarettes to wean themselves off smoking and eventually quit altogether.

And among people who don't want to or can't quit completely, some have replaced cigarettes either entirely or partially with e-cigarettes, with perceived health improvements.

But using them to cut down on regular cigarettes may not help. As Professor Simon Chapman, from Sydney University's School of Public Health, points out, "Everyone assumes that if you cut down the number of cigarettes you smoke each day by also vaping, that this will reduce your risk of harm. Unfortunately, four very large cohort studies have all found that just reducing, as opposed to quitting, confers very little health benefit."

Can they be sold in Australia?

Nicotine cannot be sold or supplied in Australia except in cigarettes and other tobacco and registered NRT products. As such, retailers can't legally sell e-cigarettes in local stores, and there are fines for selling it illegally.

So Australians who buy nicotine for e-cigarettes usually buy it online from overseas in small 'personal use' quantities, and that's not currently prohibited under Australian Customs law. However, some state laws override this, including Queensland and Victoria, where possession of nicotine liquid is currently banned.

As for smoking nicotine-free varieties, some states also ban the sale of products that look like cigarettes, including food and toys, and a recent case in WA upheld this law in relation to e-cigarettes.

What's the story overseas?

In the US, the Food and Drug Administration is planning to regulate e-cigarettes, requiring registration of products and warning labels stating they contain the addictive substance nicotine, and banning sales to under-18s. This proposal has occurred in the context of an increase in complaints about health effects, including difficulty breathing, headache, cough, dizziness, sore throat, nose bleeds, chest pain and other cardiovascular problems.

Similar regulations will take effect in the EU from 2016, including an advertising ban and the stipulation that products be childproof.

Verdict

While smoking e-cigarettes appears to be safer than regular cigarettes, at least in the short term, there is not enough long-term research on their effects. For current non-smokers especially, it's best to avoid them until more is known about their safety. If you're trying to kick the habit, first try conventional NRT products or another approved method, such as counselling – call Quitline on 13 78 48 for more info, or visit quitnow.gov.au.

As Professor Mike Daube, President of the Australian Council on Smoking and Health (ACOSH) points out, "The reality is that these products are still new; the potential benefits are still in doubt; and there are significant concerns about possible short and long-term harms."

But others are concerned that it could be dismissing a valuable weapon in the quitting arsenal.

As Professor Anne McNeill, Professor of Tobacco Addiction from the National Addiction Centre, King's College London, argues, "Cigarette smoking is so uniquely dangerous that anything we can do to encourage smokers to stop should be welcomed. Smoking is now concentrated among our most disadvantaged groups in society, for whom I think e-cigarettes could be a game changer."