Three lawsuits against e-cigarette start up Juul Labs, uncovered by Wired reporter Nitasha Tiku, allege that Juul’s patented recipe stoked the users’ nicotine addictions. One of the suits was filed in New York by the mother of a teen who started Juuling when he was 15 years old. Now, he can’t stop, the suit alleges, “even though it subjects him to disciplinary measures at home and at school.”

The complaints, filed in the US District Court in Northern California, the San Francisco Superior Court, and US District Court in New York, specifically reference a key ingredient in Juul’s recipe: compounds called nicotine salts. Nicotine salts form in the heat-dried tobacco leaves that are rolled into most cigarettes, and they’re said to be easier to inhale than the free-base form of nicotine found in cigars, pipe tobacco, and many other vapes.

In a recent study, researchers tested how two Juul flavors stacked up against nine other vapes. They found that the Juul vape juices contained more nicotine and less of that harsh free-base than the other brands, according to a paper published in the journal Chemical Research in Toxicology in May. That means Juul packs a powerful nicotine punch in a palatable package.

“It’s imperative that we figure it out, and fast.”

The three suits all include the same image from Juul’s patent: a chart that shows certain nicotine salts deliver even more nicotine into the bloodstream than a Pall Mall cigarette. But Gideon St Helen, a tobacco researcher at the University of California, San Francisco, cautions against over-interpreting that data without knowing more about how the company produced it. Blood nicotine levels can rise much higher after smoking conventional cigarettes than the levels we see on that graph, he says in an email to The Verge. “[W]ithout seeing the details of how Juul conducted these studies, and without studies by independent researchers, these claims and counterclaims are hard to verify or refute,” he says.

All three complaints also target Juul Labs’ branding and marketing strategies, which the two California suits allege were built “around creating, and addicting, an entirely new group of customers who are not regular smokers.” But the company has said that’s not the case: “Juul is intended for adult smokers only who want to switch from combustible cigarettes,” spokesperson Victoria Davis told The Verge in early July. She added in an emailed statement today: “Juul Labs does not believe the cases have merit and will be defending them vigorously.”

But Juul has run into trouble about its marketing before. In April of this year, the FDA told Juul Labs the agency needed more information about the company’s marketing strategy. “We don’t yet fully understand why these products are so popular among youth,” FDA commissioner Scott Gottlieb said in a statement at the time. “But it’s imperative that we figure it out, and fast.”