Heated tobacco products — or HTPs — have grown from a niche Japanese market experiment into a globally significant product category reshaping how both the tobacco industry and public health authorities think about harm reduction. For Irish smokers considering alternatives to cigarettes, understanding what HTPs are, how they work technically, and how their risk profile compares to both cigarettes and e-cigarettes is genuinely useful information that goes well beyond the marketing claims of any manufacturer.
The Technology: Heating Without Burning
Conventional cigarettes burn tobacco at approximately 600°C, generating combustion and pyrolysis that produces thousands of chemical compounds — including the tar, carbon monoxide and carcinogens responsible for most smoking-related disease. HTPs heat real tobacco to between 250°C and 350°C: hot enough to release nicotine and flavour compounds from the leaf, but below the combustion threshold at which these highly toxic pyrolysis reactions occur. The aerosol produced contains nicotine and tobacco-derived flavour chemistry, but in dramatically lower concentrations of harmful compounds than cigarette smoke.
Philip Morris International’s IQOS is the market leader globally and the most established brand in Ireland. It uses a specialised tobacco stick — sold as HEETS or TEREA — inserted into a holder that heats the tobacco via a ceramic blade or induction element. The device’s internal processor maintains a precise temperature profile for approximately fourteen puffs or six minutes — comparable in duration to smoking a cigarette. British American Tobacco’s glo uses a convective heating approach at slightly higher temperatures; Japan Tobacco International’s Ploom uses lower-temperature extraction. Each system uses proprietary consumables in a deliberately closed ecosystem that prevents cross-brand compatibility.
What the Evidence Shows
The evidence base for HTPs is more robust than for almost any other tobacco alternative, driven by PMI’s extensive submissions to the US FDA — which resulted in IQOS receiving a Modified Risk Tobacco Product authorisation in 2020, the first ever granted to any tobacco product. These submissions documented approximately 90–95% reductions in carbon monoxide, acrolein, benzene and other combustion-specific compounds compared to cigarettes. Independent replication has broadly confirmed these findings while noting that some volatile organic compounds and tobacco-specific nitrosamines are reduced to a lesser extent than manufacturer data initially suggested.
The critical caveat is that nicotine delivery from HTPs is comparable to cigarettes, meaning addiction maintenance is fully equivalent. Long-term epidemiological data on health outcomes for HTP-only users remains unavailable — the product category has only been in widespread use since 2016. The current scientific consensus is that HTPs are substantially less harmful than cigarettes, somewhat more harmful than well-formulated e-cigarettes, and that the precise magnitude of long-term risk reduction will not be fully established for another decade of population-level observation.
Where HTPs fit in the harm reduction landscape: they are a meaningful option for smokers who cannot successfully switch to vaping. They do not eliminate nicotine dependency and carry their own risk profile that is distinct from both cigarettes and e-cigarettes. For most smokers, vaping offers a greater potential harm reduction with comparable or better cessation support outcomes.
Vaping vs HTPs: The Direct Comparison
On the harm reduction spectrum, vaping has the advantage over HTPs because it involves no tobacco and no heating of biological material. E-cigarette aerosol is chemically simpler and contains fewer identified harmful compounds than HTP aerosol, which still contains tobacco-derived compounds absent from e-cigarette vapour entirely. This is reflected in scientific literature and in public health guidance from bodies including the UK Health Security Agency.
HTPs have a decisive advantage for smokers who find vaping’s flavour profile unsatisfying. Because HTPs heat real tobacco leaf, their aerosol contains the full sensory complexity of tobacco flavour in a way that even excellent tobacco-flavoured e-liquids cannot reliably replicate. For long-term heavy smokers with a strong attachment to the specific taste of tobacco — rather than simply to the nicotine delivery — this sensory fidelity is often the deciding factor in whether a smoke-free switch is sustained beyond an initial trial period.
Practical Considerations in Ireland
In Ireland, HTPs are regulated as tobacco products under the same framework as cigarettes — the Tobacco Products Directive and Public Health (Tobacco) Acts apply in full. They may not be used in smoke-free environments, meaning the same indoor restrictions as cigarettes apply: no use in enclosed workplaces, restaurants, bars or on public transport. This is a significant practical disadvantage compared to vaping, which is subject to different and in some contexts somewhat less restrictive usage rules, particularly in outdoor environments and semi-public spaces.
IQOS devices and HEETS tobacco sticks are available in Irish convenience stores, newsagents and petrol stations. The glo system has a growing retail presence. Both brands offer trial devices at reduced cost — the most sensible approach before committing to ongoing consumable expenditure. At approximately €6–8 for a pack of twenty HEETS, the ongoing cost of HTP use is broadly comparable to cigarettes and significantly higher than a well-managed vaping setup.
Who Should Consider HTPs
HTPs are most relevant for three specific user profiles: smokers who have tried vaping multiple times and found the flavour or delivery profile persistently unsatisfying; heavy long-term smokers with a deep attachment to tobacco taste that even excellent e-liquids cannot replicate; and people who are comfortable managing a device with proprietary consumables and a closed ecosystem, rather than the open, customisable world of pod systems and tank vaping. For everyone else — and particularly for people making their first attempt to switch from cigarettes — e-cigarettes remain the better-evidenced, more flexible and ultimately more cost-effective starting point.