INTRODUCTION
 
Electronic nicotine delivery systems (ENDS), commonly referred to as electronic cigarettes or "e-cigarettes," function by delivering aerosolized particles containing nicotine or other substances to the user.(1) First introduced to the U.S. market around 2007, these devices emerged as an alternative for individuals attempting to quit traditional cigarettes.(2) However, they have been shown to be equally harmful-if not more so-as they deliver higher levels of nicotine along with other potentially toxic chemicals, such as dichloromethane, acetaldehyde, acrolein, nitrosamines, and various agents that remain insufficiently characterized in the scientific literature.(3) Consequently, another significant concern is the limited research on these devices and their long-term effects, particularly given their relatively recent introduction to the Brazilian market.(2) Therefore, understanding the factors contributing to their increased use among adolescents, the short- and long-term effects of such use, and the broader context of the issue in Brazil warrants further investigation.

 
ARE ENDS BETTER THAN CONVENTIONAL CIGARETTES?
 
E-cigarettes are often marketed as a safer alternative to traditional cigarettes. Unlike conventional tobacco products, ENDS operate without combustion, thereby reducing the release of numerous toxic substances associated with smoking-related health issues.(1) For instance, emissions from e-cigarettes typically contain lower levels of particulates and carcinogenic compounds compared to traditional cigarette smoke. However, the perception that ENDS are significantly safer remains a topic of ongoing debate. As relatively recent innovations, their long-term health effects are not yet fully understood, resulting in an incomplete and evolving body of evidence. (2) Moreover, inconsistencies in product labeling and wide variability in nicotine and chemical content across different brands and models further complicate efforts to assess their safety. While ENDS may produce fewer harmful emissions than traditional cigarettes, they still expose users to nicotine-a highly addictive substance-and other potentially hazardous chemicals, raising concerns about their overall impact on health.(1)
 
WHY ARE ENDS DANGEROUS?
 
ENDS are associated with several significant health risks. One of the primary concerns is their efficient delivery of nicotine, which can lead to rapid dependence and adverse health effects, such as increased heart rate and blood pressure. In extreme cases, nicotine toxicity may result in seizures, respiratory failure, or even death. The vapor produced by ENDS contains various harmful chemicals, including ultrafine particles, volatile organic compounds, and carbonyl compounds-some of which have been detected at levels comparable to those found in conventional tobacco smoke.(1) These substances can irritate the respiratory tract, induce oxidative stress, and trigger inflammation. Moreover, flavoring agents commonly used in ENDS liquids, such as cinnamon, have demonstrated cytotoxic effects, raising concerns about the long-term consequences of inhaling such additives. (3) Although ENDS emit fewer harmful substances than traditional cigarettes, secondhand vapor still exposes non-users to potentially dangerous chemicals, the full extent of which remains unclear. Furthermore, the appealing packaging and flavors of ENDS liquids present a serious hazard, particularly to children, as accidental ingestion can lead to severe health complications.(1)
 
ADOLESCENTS AS MAIN USERS OF ENDS
 
With the rise in e-cigarette use, one population of particular concern is adolescents. A recent systematic review involving individuals aged 8 to 20 years from 69 countries and territories reported a pooled prevalence of 17.2% for ever-use (any lifetime use) of ENDS and 7.8% for current use (use within the past 30 days).(4) ENDS are as addictive as conventional cigarettes and can cause neurocognitive effects, including impaired reflexes, deficits in attention and reasoning, and mood disorders. Furthermore, nicotine exposure at a young age can result in permanent brain damage, increase the risk of addiction, and contribute to sustained tobacco use into adulthood.
 
CONSEQUENCES OF ENDS USE
 
ENDS pose significant health risks due to their chemical composition and the interactions these substances have within the human body. For example, e-cigarettes contain propylene glycol and vegetable glycerin-compounds that are highly toxic to lung cells. Generally, the greater the number of ingredients, the higher the potential harm to health.(1) The consequences of ENDS use can be broadly categorized into five main areas: respiratory problems, cardiovascular damage, nicotine addiction, mental health issues, and substance abuse.
 
WHAT IS THE CONTEXT OF ENDS IN BRAZIL?
 
The sale, importation, storage, transportation, and advertisement of e-cigarettes in Brazil have been prohibited by the National Health Surveillance Agency (ANVISA) since Collegiate Board Resolution (RDC) No. 46 of 2009. In 2024, the regulation was reviewed and reaffirmed by the Brazilian government with even stricter measures, including a ban on the manufacture and distribution of ENDS within the national territory. (5) It is also important to note that electronic cigarettes are subject to Decree-Law No. 8.262 of 2014, which prohibits the use of any smoking device in enclosed public or private collective spaces.(6)
 
In 2022, the Covitel study was conducted in Brazil to estimate the prevalence of e-cigarette use among Brazilian adults. The study found that among 1,800 individuals, the prevalence of current commercial cigarette smoking was 12.2%. Furthermore, young adults aged 18 to 24 had the highest rates of e-cigarette experimentation, with usage being more common in the Central-West region and among individuals with higher levels of education.(6)
 
CONCLUSION
 
In summary, while often considered a healthier alternative to traditional cigarettes, ENDS are, in fact, equally harmful-or potentially more so. In addition to causing nicotine dependence, they are associated with respiratory issues, cardiovascular problems, and negative impacts on mental health. Although the sale of these devices is prohibited in Brazil by ANVISA, their growing popularity among adolescents underscores the urgent need for both educational initiatives and strengthened regulatory measures.
 
AUTHOR CONTRIBUTIONS
 
MAULC, LMP, GABS, and MPCH: searching and writing. LAP and DCCS: writing, reviewing, and editing.
 
REFERENCES
 
1.           American Lung Association. E-Cigarettes and Lung Health [Internet]. www.lung.org. 2022. Available from: https://www.lung.org/quit-smoking/e-cigarettes-vaping/lung-health.
2.           Redação SBP. Dispositivos eletrônicos de entrega de nicotina (cigarros eletrônicos e similares): "Lobos em pele de cordeiro?" [Internet]. SBP. Cworks; 2018 [cited 2025 Mar 12]. Available from: https://www.sbp.com.br/imprensa/detalhe/nid/dispositivos-eletronicos-de-entrega-de-nicotina-cigarros-eletronicos-e-similares-lobos-em-pele-de-cordeiro.
3.           Khambayat S, Jaiswal A, Prasad R, Wanjari MB, Sharma R, Yelne S. Vaping Among Adolescents: An Overview of E-Cigarette Use in Middle and High School Students in India. Cureus. 2023;15(5):e38972. https://doi.org/10.7759/cureus.38972.
4.           Berry KM, Fetterman JL, Benjamin EJ, Bhatnagar A, Barrington-Trimis JL, Leventhal AM, et al. Association of Electronic Cigarette Use With Subsequent Initiation of Tobacco Cigarettes in US Youths. JAMA Netw Open. 2019;2(2):e187794. https://doi.org/10.1001/jamanetworkopen.2018.7794.
5.           Agência Nacional de Vigilância Sanitária - Anvisa. Cigarro eletrônico - Dispositivos Eletrônicos para Fumar (DEFs) [Internet]. Available from: https://www.gov.br/anvisa/pt-br/assuntos/tabaco/cigarro-eletronico.
6.           República Federativa do Brasil. Casa Civil. Decreto No. 8.262, de 31 de maio de 2014. Available from: http://www.planalto.gov.br/ccivil_03/_Ato2011-2014/2014/Decreto/D8262.htm. 
7.           Menezes AMB, Wehrmeister FC, Sardinha LMV, Paula PDCB, Costa TA, Crespo PA, et al. Use of electronic cigarettes and hookah in Brazil: a new and emerging landscape. The Covitel study, 2022. J Bras Pneumol. 2023;49(1):e20220290. https://doi.org/10.36416/1806-3756/e20220290.