Smokers who switch to electronic cigarettes to try to kick their habit are at least as likely to succeed in quitting or cutting down as users of nicotine patches, according to research published on Sunday.
In a first-of-its-kind study, researchers compared electronic, or e-cigarettes, with the more standard nicotine replacement therapy patches.
They found levels of success were comparable, with e-cigarettes - whose effects are a subject of intense debate among health experts - more likely to help smokers, who fail to quit, cut the amount of tobacco they use.
Some experts fear e-cigarettes may be a "gateway" to nicotine addiction and tobacco smoking, while others view them as the most useful method yet of cutting back and helping would-be quitters.
While the argument rumbles on, smoking continues to kill half of all those who indulge in it.
Tobacco is responsible for 6 million deaths a year and the World Health Organisation estimate that number could rise beyond 8 million by 2030.
As well as causing lung cancer and other chronic respiratory conditions, smoking is also a major contributor to cardiovascular diseases, the world's number-one killer.
The study, published in The Lancet medical journal and presented at a conference in Spain, was the first to assess whether e-cigarettes are more or less effective than nicotine patches - already recognised as useful in helping people quit smoking.
"While our results don't show any clear-cut differences... in terms of quit success after six months, it certainly seems that e-cigarettes were more effective in helping smokers who didn't quit to cut down," said Chris Bullen of New Zealand's University of Auckland, who led the study.
"It's also interesting that the people who took part in our study seemed to be much more enthusiastic about e-cigarettes than patches, as evidenced by the far greater proportion of people... who said they'd recommend them to family or friends."
Bullen's research team recruited 657 smokers who wanted to quit smoking and divided them into three groups.
They gave 292 of them 13 weeks' supply of commercially available e-cigarettes, each of which contained around 16mg of nicotine. The same number of participants got 13 weeks of nicotine patches, and the remaining 73 got placebo e-cigarettes containing no nicotine.
At the end of the six-month study, 5.7 %of participants had managed to completely stop smoking for that period.
Bullen said that while the proportion of participants who quit was highest in the e-cigarettes group - at 7.3 %compared to 5.8 %on nicotine patches and 4.1 %on placebo - the differences were not statistically significant, so the results were that the two products were comparable.
The study also found that among those who had not managed to quit, cigarette consumption was markedly more reduced in the nicotine e-cigarettes group, compared to both other groups.
Some 57 %of people using e-cigarettes had cut their daily number of cigarettes smoked by at least half after six months, compared to just over 40 %of the patches group.
Ann McNeill, a professor of tobacco addiction at the Institute of Psychiatry at King's College London, said the findings should persuade health experts to embrace e-cigarettes as a useful weapon in the battle against smoking.
"Electronic cigarettes are the most exciting new development in tobacco control over the last few decades as we have witnessed a rapid uptake of these much less harmful products by smokers," she said in an emailed comment.
"The popularity of e-cigarettes suggests that we now have a product that can compete with cigarettes, thus heralding the first real possibility that cigarette smoking could be phased out."