A heated tobacco product (HTP) is a tobacco product that heats tobacco at a lower temperature than conventional cigarettes. The heat generates an aerosol or smoke for inhalation, containing nicotine, a highly addictive substance, and other chemicals. HTPs may also contain additives not naturally present in tobacco, including flavoring chemicals. HTPs generally heat tobacco to temperatures below 600 °C (1100 °F), which is lower than the combustion temperature of conventional cigarettes.
HTPs use embedded or external heat sources, heated sealed chambers, or product-specific customized cigarettes. Unlike e-cigarettes, which vaporize nicotine-containing liquids, HTPs typically use leaf tobacco or another solid form, though some hybrid models can use both solid tobacco and e-liquids. There are various types of HTPs. The two most common designs are battery-powered devices that heat tobacco leaf (e.g., IQOS, glo, Pax) and devices that heat tobacco using a carbon ember (e.g., Eclipse, REVO, TEEPS). Similar devices exist for heating cannabis.
A 2016 World Health Organization report found no evidence supporting claims of reduced risk or health benefits compared with conventional cigarettes. A 2018 Public Health England review concluded that HTPs may pose less risk than conventional cigarettes but more risk than e-cigarettes. Some HTP aerosols have been found to contain nicotine and carcinogen levels comparable to those of traditional cigarettes. Although HTPs may be less harmful than smoking, the UK Committee on Toxicity recommends complete cessation instead of switching to HTPs. There is insufficient evidence on the effectiveness of HTPs for smoking cessation, or on the risks of second-hand exposure. Limited evidence suggests that toxic emissions from HTPs are higher than those from e-cigarettes. Some smokers have reported HTPs to be less satisfying than traditional cigarettes.
Tobacco companies initially began developing alternative tobacco products in the 1960s. HTPs were first marketed in 1988 but were unsuccessful. The industry’s renewed interest in HTPs has been partly linked to global declines in tobacco consumption. The latest generation of HTPs has been promoted as a potential—though unproven—harm-reduction option. Existing smoking bans vary in whether they apply to HTPs.
History
As early as the 1960s, tobacco companies began developing alternative tobacco products to supplement the cigarette market. The first commercial HTP was the Premier by R. J. Reynolds, a smokeless cigarette launched in 1988 that was widely described as difficult to use. Many smokers disliked its taste, and it was not popular during test marketing in Arizona and Missouri. The product resembled a traditional cigarette and required combustion to move smoldered charcoal past processed tobacco containing more than 50% glycerin to produce an aerosol.
In 1989, after spending $325 million on development, R. J. Reynolds withdrew the Premier following recommendations from the American Medical Association and other organizations that the US Food and Drug Administration (FDA) restrict or classify it as a drug.
The Premier concept was later revised and reintroduced as the Eclipse in the mid-1990s. The Eclipse remained available in limited distribution , and was promoted through viral marketing. Reynolds American later introduced Revo, describing it as a repositioned Eclipse, but the Revo was withdrawn in 2015.
The Steam Hot One was sold in Japan by Japan Tobacco.
In October 1998, Philip Morris launched the Accord in the United States. It was a specialized cigarette designed for use with an electric heating system. Advertisements suggesting reduced risk were drafted but never released. The company also launched the Accord in Osaka, Japan, renaming it Oasis. The battery-powered, pager-sized product was marketed as a "low-smoke" option. In 2007, Kenneth Podraza, then Vice President of Research and Development at Philip Morris USA, sought endorsement from the Surgeon General of the United States, but received no response. Few consumers adopted the Accord, and many who did continued using traditional cigarettes. Production ended in 2006.
In 2007, Philip Morris International introduced the Heatbar, a product similar to the Accord. About the size of a mobile phone, it heated specially designed cigarettes rather than burning them. The Heatbar failed to generate significant consumer interest, and was discontinued after studies reported its only notable benefit was reduced second-hand smoke. Both the Accord and Heatbar are considered precursors to Philip Morris International's current HTPs. Many early HTPs were not commercially successful and were withdrawn shortly after launch.
Leading up to 2018, increasing tobacco control measures prompted the tobacco industry to develop alternative tobacco products such as HTPs. A global decline in tobacco consumption—which threatens industry profits—has also driven companies to create and promote new products. The introduction of HTPs may have been influenced by the rapid rise of e-cigarettes beginning around 2007, initially led by independent companies before multinational tobacco firms entered the market.
Falling global cigarette consumption and declining adult smoking prevalence (from 24% in 2007 to 21% in 2015), combined with the implementation of measures such as the WHO Framework Convention on Tobacco Control, may have encouraged tobacco companies to pursue alternative products to maintain profits and political influence. T. L. Caputi argues that the widespread availability of e-cigarettes and dissatisfaction among some users with a lack of "throat-hit" could create opportunities for HTPs. Philip Morris International has expressed interest in a future without traditional cigarettes, although public health campaigners and industry analysts have questioned the likelihood that e-cigarettes or products like IQOS will replace them.
Health effects
A 2016 Cochrane review found that it was unclear whether the use of heated tobacco products (HTPs) would “substantially alter the risk of harm” compared with traditional cigarettes. In the same year, a World Health Organization report stated that claims of reduced harm from HTPs were based largely on industry-funded research, and independent evidence to support these claims was lacking. It also reported evidence indicating that HTPs may be as dangerous as traditional cigarettes.
In 2016, Action on Smoking and Health (UK) emphasized the need for independent research, citing "the tobacco industry's long record of deceit" regarding the health risks of smoking. , it remained impossible to quantify the health risks of HTP use due to the limited amount of available health data. The short- and long-term adverse effects of HTPs were also unclear. , only a limited number of independent studies had been conducted on HTPs, and further research was expected to improve understanding of their health effects.
The wide variety of HTP designs poses challenges for researchers, as different products may produce different effects. One study found that about half of users believed HTPs to be safer than traditional cigarettes.
Given the wide range of electronic cigarette products in the UK, it remains unclear whether HTPs provide any notable benefit as harm reduction devices. A 2018 Public Health England report stated that HTPs may be significantly safer than traditional cigarettes but less safe than e-cigarettes. A 2017 non-technical summary by the Committee on Toxicity recommended that smokers should completely stop using tobacco, even though HTPs were assessed as being less harmful than smoking conventional cigarettes.
A 2022 Cochrane review found evidence that measured toxin levels were lower in people using heated tobacco products than in those smoking cigarettes, although such levels may still be higher than in people not using any tobacco products.
Emissions
Heated tobacco products expose users and bystanders to an aerosol. The aerosol contains levels of nicotine, volatile organic compounds, and carcinogens comparable to those in regular cigarettes and has been found to contain higher levels of acenaphthene than cigarette smoke. Other substances typically associated with cigarette emissions—such as tar, nicotine, carbonyl compounds (including acetaldehyde, acrolein, and formaldehyde), and nitrosamines—are also found in HTP emissions. A 2017 study found that indoor use of HTPs increased air levels of carbon monoxide and formaldehyde by 10 percent.
Another 2017 study reported that HTPs generate emissions containing metal particulates, organic compounds, and aldehydes, and found that airborne contaminant concentrations were lower than those produced by traditional cigarettes, though HTP use still decreases indoor air quality.
A 2018 Public Health England report stated that, compared with cigarettes, HTPs are likely to expose users and bystanders to lower levels of particulate matter and harmful and potentially harmful compounds (HPHCs), though the degree of reduction varies across studies. The report also found that less nicotine is typically inhaled from HTPs than from cigarette smoke, and that exposure to mutagenic and other harmful substances is lower. However, reduced exposure does not necessarily correlate with reduced health risk. Low levels of exposure can also raise the risk of cancers, stroke, and other cardiovascular diseases compared with non-smokers. Although lower emissions have been observed, there was no evidence as of 2018 that switching to HTPs reduces overall risk for smokers. In 2017, the Committee on Toxicity reported that HTPs do not reduce exposure to, or the potential for addiction to, nicotine; several inhaled substances remain carcinogenic.
Physiological responses to heated tobacco emissions, including inflammation, metabolic changes, and carcinogenesis across multiple organ systems, are not well characterised due to limited research, particularly in animal models. A 2018 in vitro study found a less harmful pathophysiological response in human organotypic oral epithelial cultures exposed to HTP emissions. A 2016 animal study reported that HTP emissions did not increase surfactant lipids and proteins, inflammatory eicosanoids, metabolic enzymes, or various ceramide classes in exposed mice compared with those exposed to cigarette smoke. The study also noted that excessive use (40 sticks per day) can lead to eosinophilic pneumonia in humans despite reduced toxicant levels.
The population-level impact of HTP emissions is unclear. As of 2018, studies on second-hand HTP emissions varied widely and were often affiliated with manufacturers. There is disagreement over the extent and composition of HTP emissions. A reduced risk to bystanders is expected where HTPs are used instead of cigarettes. Limited evidence suggests that toxic exposure from HTP emissions is higher than from e-cigarettes. Because no safe level of exposure to carcinogens exists, it is difficult to determine how much HTPs reduce health risks overall.
Addiction and quitting
HTPs contain the highly addictive chemical nicotine. The nicotine content of HTP emissions is similar to that of traditional cigarette smoke, suggesting a comparable potential for addiction and dependence. There is insufficient evidence on whether HTPs are effective for quitting smoking.