Ever since e-cigarettes began surging in popularity, they have posed a vexing problem: these nicotine-delivery devices may help some adults quit smoking, which is more dangerous than vaping, but also may addict non-smokers to nicotine, especially curious teenagers.

The Trump Administration took a significant step last week to reduce the appeal to young non-smokers. The hope is that the move will not also lead fewer adult smokers to quit.

Flanked by Health and Human Services Secretary Alex Azar and First Lady Melania Trump, President Donald Trump announced that the Food and Drug Administration would ban flavoured e-cigarette products from the market — except those that taste like tobacco smoke. Research backs the common-sense assumption that differently flavoured vaping fluids — mango, mint, cotton candy — appeal to high schoolers unused to tobacco’s harsh taste. Existing smokers seeking alternatives, meanwhile, would still have vaping liquids in a taste to which they have become accustomed.

The move is an implicit admission that the FDA’s efforts to date have not done enough to arrest youth vaping. Last November, regulators introduced seemingly strict new rules on the sale of flavoured e-liquids; they could be sold only in special, age-controlled shops or on websites with careful age verification. But disheartening new federal data show that youth vaping remains an enormous problem. Initial information from the National Youth Tobacco Survey shows that more than a quarter of high schoolers report having used an e-cigarette in the past 30 days — mostly fruit or mint-flavoured.

The FDA might have given its previous rules more time to play out. But based on the alarming survey, the agency was right to act. The priority must be to prevent a new generation of nicotine addicts. Even if vaping is less dangerous than smoking combustible cigarettes, nicotine itself affects adolescent brain development. The health effects of vaping also remain uncertain — a fact underscored by a spate of recent illnesses and deaths apparently related to e-cigarette use.

But e-cigarettes do appear to have substantial appeal to smokers seeking alternatives. A study published in January found that smokers who were given e-cigarettes were more likely to successfully stop smoking combustible cigarettes than those given nicotine patches or gums. Drug-based smoking-cessation products are also an effective option, but there is no doubt a class of people for whom vaping is the best off-ramp. And some of them might be less interested without a variety of flavour options.

This may not be the end of the road for flavoured e-cigarette products. Manufacturers can apply next year to regain access to the US market; they would have to convince the FDA that their products protect public health. This means FDA regulators must still consider whether there is a way to market flavoured e-liquids exclusively to those who should have access to them. In the meantime, they should move forward with banning flavoured cigars, too.