The results showed that, for each time period, almost a third of recent quitters reported to have relapsed. The researchers found no difference in relapse rate among those who used NRT for more than six weeks, with or without professional counselling. No difference in quitting success with use of NRT was found for either heavy or light smokers.

Mr Alpert said that even though clinical trials have found NRT to be effective, the new findings demonstrate the importance of empirical studies regarding effectiveness when used in the general population.

He added that using public funds to provide NRT to the population at large is of questionable value, particularly when it reduces the amount of money available for smoking interventions shown in previous studies to be effective, such as media campaigns, promotion of no smoking policies, and tobacco price increases.

Smoking cessation medications have been available over the counter for more than a decade.

Co-author Gregory Connolly, director of the Centre for Global Tobacco Control at HSPH, said: “What this study shows is the need to approve only medications that have been proven to be effective in helping smokers quit in the long-term and to lower nicotine in order to reduce the addictiveness of cigarettes.”

The study was published online by the journal Tobacco Control.