Catania, April 7, 2025 – Weight gain remains one of the most feared side effects among those who decide to quit smoking. According to consumer opinions and preliminary industry data, reduced-risk products—such as electronic cigarettes—could represent a viable strategy to help control post-cessation weight gain. But what does the science say? A new systematic review conducted by the CoEHAR research team, part of the In Silico project, and published in the journal Archives of Medical Research, examines the effects of substituting traditional cigarettes with electronic nicotine delivery systems (ENDS) on body weight.
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Average weight gain one year after quitting smoking ranges between 4.67 and 4.8 kg, with over 10% of former smokers gaining more than 10 kg.
- Exclusive use of e-cigarettes, on the other hand, is associated with modest long-term weight gain and minimal or nearly no increase in the short term (less than six months).
- While the evidence is promising, it is not yet sufficient to draw definitive conclusions: the review highlights the urgent need for larger, methodologically robust clinical trials.
“As suggested by several international surveys, consumers believe that reduced-risk products may help manage weight gain after quitting smoking. That’s why we set out to analyze the actual impact of ENDS use on the body weight of those who reduce or quit smoking,” said Giusy Maria Rita La Rosa, author of the review.
The study was conducted by the CoEHAR In Silico team under the guidance of Dr. Renée O’Leary. It included nine articles from eight studies conducted between 2010 and 2024, comprising: 5 randomized controlled trials (RCTs), 2 cohort studies, 1 quasi-experimental study.
As for methodological quality: 2 studies were assessed as high risk of bias, 5 had some concerns, 1 was considered low risk
“Our analysis shows that replacing traditional cigarettes with e-cigarettes may have an impact on body weight,”explained Dr. Renée O’Leary. “However, the direction and magnitude of this impact vary across studies. The current evidence is not yet sufficient to draw firm conclusions, but it does open the door to new research on a very real concern.”
Healthcare professionals are advised to monitor weight changes in patients using reduced-risk products to quit smoking. Weight gain could become a barrier to complete transition and thus compromise long-term success. Understanding the full spectrum of health effects—including impacts on weight—is essential.
The CoEHAR study marks a significant first step in this direction, while also underscoring the need for further investigation to provide safe and effective clinical recommendations.