Today, e-cigarettes are typically made with nicotine from tobacco. Before Juul, they generally contained 1 percent to 2.4 percent of nicotine extract that had not been treated with acids. Juul increased the nicotine “kick” by using up to 5 percent nicotine, and made that palatable by adding organic acids to reduce the harshness, just as the industry had explored doing decades earlier with cigarettes.

Other characteristics of Juul’s design also make it easier for young people to begin using e-cigarettes. They include the use of flavor additives like mint and fruit. Responding to criticism, Juul recently stopped selling some flavors in retail establishments and limited them to online, age-verified sales. And for young people at school, the size of the vapor cloud — small but with high nicotine — makes it less likely to be detected.

Each Juul cartridge with 5 percent nicotine delivers 200 puffs, compared to the 10 to 15 puffs of a traditional cigarette. As a pediatrician, I am very concerned about the possibility of increased daily nicotine consumption among some young people.

I had hoped there could be a substitute for traditional cigarettes that offers a less risky nicotine delivery system for those who are addicted to nicotine, have not been able to quit smoking and need an “off ramp.”

Juul is not that product. Its fundamental design appears to ease young people into using these e-cigarettes and ultimately, addiction. Those who support the use of e-cigarettes to help addicted adults quit cigarettes should support clamping down on brands like Juul that appeal to young people.

Last week, James Monsees , a co-founder of Juul Labs, testified to Congress that “our company ha s no incentive to see minors use our products. We know there is skepticism on this point, but it is simply the truth.” If that’s the case, then the company needs to change the design of its product. If it doesn’t, the F.D.A. should reject it as a new tobacco product .

The company should also make public any clinical studies and consumer perception surveys. And now that the tobacco giant Altria owns a 35 percent stake in Juul Labs, which has an estimated $38 billion valuation, it should disclose what it knows from its own long experience about reducing harshness and increasing nicotine. This will help the F.D.A. encourage products that help smokers quit but do not initiate k id s and young adults into the habit.

The words of Addison Yeaman , the general counsel for the tobacco company Brown & Williamson, written in 1963, are equally applicable today: “We are, then, in the business of selling nicotine, an addictive drug.” A long and tragic history has taught us that nicotine addiction often begins as a pediatric disease.

David A. Kessler, a professor of pediatrics at the University of California, San Francisco, was commissioner of the Food and Drug Administration from 1990 to 1997.

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