WASHINGTON — Juul Labs has soared to the top of the United States e-cigarette market in just three years with its high-nicotine products that give off just a wisp of vapor.
Now, facing public backlash and overseas restrictions, the company is working on a way to lower the nicotine in its pods — but still maintain a potent punch from the addictive chemical.
Juul is developing a pod that is higher in vapor, which, experts say, can enhance the rate at which nicotine is absorbed in the body.
People knowledgeable about the development of the higher-vapor pod say the company hopes it will appeal to cigarette smokers who are accustomed to a bigger cloud. And by reducing the nicotine level, even while magnifying the effect of the nicotine, Juul presumably would be able to meet stricter nicotine limits in many countries.
It is unclear what levels of nicotine would be in the new design, and a variety of models are under development for different markets. The new pods are being designed for sale overseas, where Juul wants to replicate the success it has had in the United States.
But in the European Union, where Juul plans to expand, and in the United Kingdom, where it is already on the market, the nicotine limit for e-cigarettes is 20 milligrams per milliliter of fluid — about a third of the amount in the most popular American Juul pod.
A lower nicotine version is also on sale in the United States, but, at 23 milligrams of nicotine per milliliter of fluid, it still exceeds European Union requirements.
Joshua Raffel, a Juul spokesman, declined to answer numerous questions about the new pod. In an interview, he would only say: “We are always looking to create products that help adult smokers switch from combustible cigarettes and limit appeal to youth.”
Juul has not ruled out marketing the product in the United States, but would need the Food and Drug Administration’s approval to do so.
Some experts said the higher vapor could potentially make the pods even more addictive, increasing the risk particularly to young people, whose developing brains are more susceptible to the addictive qualities of nicotine.
Micah Berman, associate professor of public health and law at The Ohio State University, said the amount of nicotine in a pod can be deceptive — what really matters is how much the body actually absorbs.
“One of the things with cigarette design over the years is that they have figured out how to maximize the impact of nicotine in cigarettes,” Mr. Berman said.
Of Juul’s plans, he said: “If it’s a change that reduces test levels of nicotine — the amount you would identify as being in the pod itself — but doesn’t actually change the biological level, then that’s certainly problematic. It’s more like cheating the test.”
But Neal Benowitz, a professor of medicine at the University of California, San Francisco, said that increasing the vapor might indeed make Juul more useful to smokers who want to quit.
“For smoking cessation, you need to have a satisfying delivery system with a good amount of nicotine with a small amount of aerosol,” Dr. Benowitz said. “But if you are vaping because you like the sensory aspects of it, then you want more aerosol. Right now, Juul is a good nicotine delivery device but the quality is not the same as a cigarette. I could see why some people might like a product that generates more aerosol and is more cigarette-like.”
The new pods are expected to be slightly longer than the existing pods, but are designed to fit the current Juul device.
The San Francisco-based Juul, which began selling its vaping device by the same name in 2015, has now captured more than 70 percent of the e-cigarette market share in the United States. Its success has been met with harsh public criticism over an epidemic of teenage vaping, and increasing government pressure to stop it.
Earlier this month, facing a deadline from the Food and Drug Administration, Juul announced major changes in its sales and marketing practices aimed at reducing youth access to its devices and popular flavored pods.
A sleek, electronic device that looks like an elongated flash drive, Juul works by heating a liquid flavor pod that contains nicotine and benzoic acid. When Juul users inhale, they get a very quick and powerful burst of nicotine.
The F.D.A.’s biggest public health goal in this administration has been getting smokers to quit, and reducing the 480,000 annual deaths in the United States from cigarette-related disease. To do so, Dr. Scott Gottlieb, the commissioner, has encouraged the development of alternatives like e-cigarettes and, early in his tenure, extended the deadline for them to meet tough new agency rules.
But this strategy backfired when Juul and other e-cigarettes became immensely popular with youths, and the agency recently restricted sales of certain flavors that appeal to youths.
The other half of the F.D.A.’s plan is to reduce nicotine to nonaddictive levels in traditional cigarettes. The agency has started that process, but the tobacco companies have made clear they will fight it. There has been no agency announcement yet regarding limits on nicotine in e-cigarettes.
Experts in e-cigarette engineering said there were a number of ways Juul could amp up the vapor, or aerosol, in its products. Edward Hensel, associate dean of engineering at the Rochester Institute of Technology, said one way is by adjusting the heating coil, inside the flavor pod.
“They can use the same battery and the same electronics but by changing the coil you can have a different amount of power, and so aerosolize more product,” Dr. Hensel said.
Some public health advocates noted another consequence of a more powerful pod.
“More vapor is more secondhand vapor,” said Chris Bostic, a deputy director at Action on Smoking & Health, a public health group working to eliminate tobacco use. “A bigger cloud of vapor sounds to me like a bigger problem for bystanders.”