Flavour Restrictions Could Do More Harm Than Good, New Research Warns

A peer-reviewed study published this month in Health Research Policy and Systems has produced a sobering finding for regulators considering restrictions on vaping flavours: removing them could increase adult smoking at a scale that outweighs any protection offered to young people.

The study, produced by researchers at the University of Bristol and the University of Bath and originally commissioned by Public Health England, was designed as a practical decision-making tool for policymakers. It applies available data to a specific question: if flavoured vaping liquids in the United Kingdom were restricted to tobacco, menthol, or no flavour at all, would public health improve or worsen overall?

The answer the model returned was unambiguous. It would worsen.

What the model found

The model estimated that 841,302 smokers and ex-smokers in the UK do not smoke because flavoured vaping liquids are available. That figure dwarfs the estimated youth exposure on the other side of the ledger. Among non-smoking young people aged 11 to 20, the model estimated that 125,034 experiment with vaping as a result of flavoured e-liquid availability, and that 48,764 subsequently go on to smoke.

The scale of the disparity matters. Even accounting for the youth smoking risk that flavours may contribute to, the model found that restricting the market to unflavoured or tobacco-flavoured products would produce a net increase in smoking across the population. In the language of public health, flavour restrictions would not represent a net benefit. They would represent a net harm.

The methodology draws on data from Action on Smoking and Health surveys, the Smoking Toolkit Study, and the Office for National Statistics. It was updated using evidence available in November 2024. The authors are transparent about the model’s limitations: it uses self-reported anticipated behaviour, not observed responses to an actual ban, and it cannot capture every possible downstream effect. The researchers themselves caution that the tool should be used alongside evidence from comparable regulatory environments, not in isolation.

Why flavours matter for adult cessation

The relationship between flavour availability and adult smoking behaviour is not incidental. Among current adult dual users and those who had quit within the previous year using a vape, 59 per cent said they would smoke more tobacco or return to smoking if flavours became unavailable. Among ex-smokers who vape, 11 per cent said the same.

These are not trivial numbers. They represent millions of people who are currently not smoking, and whose continued abstinence is tied, in part, to the availability of a product that actually satisfies them. Adults are not children. They have the right to make informed choices about the products they use to protect their own health. Telling a 45-year-old former smoker that the flavour of the vape that helped them quit is no longer permitted is not a neutral regulatory act. It is a decision that carries real health consequences, and those consequences fall on real people.

This is consistent with what QLS has long argued: that harm reduction works when alternatives are accessible, acceptable, and affordable. Acceptable means adults can find products they are willing to use long enough to break the cigarette habit. Flavour is part of acceptability. Restricting it does not make vaping more neutral. It makes vaping less useful, and cigarettes, by comparison, more appealing.

The gateway question

The study also addresses the gateway hypothesis directly, and with appropriate caution. While the model incorporates the assumption that some youth vaping leads to subsequent smoking, the authors note that the relationship between the two behaviours is unlikely to be fully explained by a direct gateway mechanism. Shared risk factors, including social environment and pre-existing disposition toward risk, are likely to account for a significant portion of the observed correlation.

This distinction is not a technicality. It has profound implications for how policy is designed and who bears the cost of getting it wrong.

The gateway argument is one of the most frequently cited objections to tobacco harm reduction, yet it has not been borne out by population-level data in any country where vaping products have been regulated and made accessible. In the United Kingdom, New Zealand, and Sweden, the expansion of vaping has coincided not with increases in youth smoking, but with accelerated declines. The observable pattern across these populations is displacement: combustible tobacco use falling as vaping rises. That is the opposite of a gateway effect. It is the definition of harm reduction working as intended. Policymakers who continue to build regulatory frameworks on an assumption the evidence does not support are not protecting young people. They are putting adult smokers at risk while doing so.

What regulators should consider

The Bristol paper was commissioned to help policymakers make better decisions. The evidence, applied to the UK population, points toward net harm from broad flavour restrictions.

Sweden’s path to a smoking rate of 3.7%, the lowest in the world, was built on a principle: that adults deserve access to alternatives they are genuinely willing to use, and that reducing the harm caused by tobacco requires meeting smokers where they are. That principle is now being tested in regulatory debates across Europe and beyond. The emerging evidence suggests that weakening the attractiveness of those alternatives, through flavour restrictions, may push a significant number of people back toward cigarettes.