Devices that deliver nicotine without smoke inhalation have potential to help smokers who cannot or do not want to stop using nicotine to reduce dramatically the risk of smoking-related disease and death.
However, for smokers to switch to these alternatives, the products need to provide what smokers expect from cigarettes.
The newest study from Queen Mary University of London evaluates safety and effects of these products and has focused on the most popular "heat not burn" product, IQOS.
The researchers compared nicotine delivery and user ratings of IQOS with those of cigarettes, Juul (the US version of a 'pod' based e-cigarette with high nicotine content), and refillable e-cigarettes.
IQOS delivered less nicotine than cigarettes. It had also lower nicotine delivery than Juul, and was less effective in reducing urges to smoke. Compared to traditional refillable e-cigarettes, IQOS provided nicotine faster, but received less favourable ratings.
The study concludes that, for quitting smoking, IQOS may be less effective than the US version of Juul (the version sold in the UK has very low nicotine delivery because of EU regulations and so it is less likely to be useful). IQOS could be as effective as refillable e-cigarettes, although study participants preferred refillable e-cigarettes.
Author Professor Peter Hajek from Queen Mary University of London said: "IQOS is likely to be useful to help smokers quit, particularly in countries like Japan, where e-cigarettes are banned; but in countries where e-cigarettes are available, they are likely to remain the more popular choice."