Banning flavored e-cigarettes has been proposed in San Francisco and elsewhere as a way to make these smokeless and nicotine vapor products less attractive to children and teens. While that may seem a sensible and self-evident conclusion, scientific evidence strongly suggests that such bans would likely do more harm than good.

Current American tobacco control policy is based on the premise that all tobacco products are hazardous, and none can offer personal or public health benefits. But it bears noting that the most addictive and most hazardous tobacco products are also the most popular. That necessarily means that safer products can, in fact, have substantial benefits. Since many smokers find it very hard to quit, e-cigarettes offer substantial benefits if they satisfy a smokers’ urge to smoke at far lower risk and are easier to quit.

Unfortunately, tobacco-control authorities fear that endorsing this view will recruit large numbers of nonsmoking teens to e-cigarettes and, eventually, to combustible cigarettes.

Historically, the only flavor shown to attract teens and others to cigarette smoking is menthol, which acts as a local anesthetic and decreases the irritation caused by cigarette smoke. Banning this one flavor in cigarettes might help secure significant public health benefits, but other flavors have not been shown to attract anyone to smoking, and have already been all-but-eliminated from cigarettes because of their unpopularity.

While cigarettes have ways to soften the irritation of smoke without adding a characterizing flavor, smokeless products and e-cigs do not. These lower-risk products require flavoring to cover the bitter taste of nicotine. Banning these flavors will increase smoking by discouraging smokers from switching to these lower-risk products. With improvements in subsequent generations of e-cigarettes, many smokers have discovered that they could satisfy their urge to smoke with e-cigarettes. Once they transition to a fruit or candy flavor, many find they no longer like the taste of tobacco, decreasing the threat of relapse.

While no nicotine product can ever be considered totally risk-free, e-cigarettes–which have no tobacco and no products of combustion—promise to be far less hazardous than cigarettes. While most public health authorities, including the surgeon general, recognize this reduction in risk for smokers who switch to e-cigarettes, they still object to the flavoring needed to make them palatable, citing the possibility of teen recruitment. It is this theoretical concern about teen recruitment that is the major driver behind the recently proposed flavor ban.

Several research papers have been published that allege that e-cigarettes recruit teens to cigarette use. Unfortunately, none of these studies explores whether the students in question would have initiated smoking had e-cigarettes not been available, and none note that the dramatic expansion in e-cigarette use in recent years is associated with record reductions in teen smoking. In fact, rates of cigarette use among teens are at historic lows. Given what we now know from the annual Centers for Disease Control and Prevention surveys of teen tobacco use, public health authorities should carefully consider the evidence suggesting that e-cigs may be serving as a gateway away from smoking for both teen smokers and those likely to initiate smoking in the future.

Taking steps to make e-cigs less palatable to current and future smokers will ensure that future rates of smoking-related diseases, which kill 480,000 people in the United States each year, remain steady. A more sensible approach would be to encourage smokers who are unable or unwilling to quit to switch to one of the lower-risk and easier-to-quit products, while continuing other efforts to reduce teen use of any nicotine delivery product, particularly given the risks posed to teens and pregnant women by the use of nicotine.

Current policy discouraging smokers from switching to safer products harms smokers without protecting teens or reducing future rates of cigarette-related addiction, illness and death.