Number of patients recruited and flow of patients within the study. A total of 66 subjects with specifically predefined smoking criteria (smoking ≥ 15 cig/day for at least the past 10 years) responded to the advert; of these, 14 subjects were not included in the study because they spontaneously seek assistance with quitting (these were then invited to attend the local smoking cessation clinic, which offers standard support with cessation counselling and pharmacotherapy for nicotine dependence). The remaining 52 subjects consented to participate into the study; of these, 12 were not considered eligible because of the exclusion criteria (6 had a high blood pressure, 2 were older than 60; 2 had a diagnosis of major depression; 1 suffered from recent myocardial infarction; 1 had uncontrolled allergic asthma). In the end, 40 volunteers were included in the study and were issued with e-Cigarette kits loaded with nicotine cartridges. By the end of the study, a total of 13 subjects were lost to follow-up due to failure of attending their control visits. Overall 27 participants were available for analyses at the 24-week follow-up visit.