As more teens are vaping than ever before, there's new scrutiny about the biggest player in the vaping game — Juul.
Some say the company's latest advertisements may be making troubling medical claims that the NBC4 I-Team found have some health experts concerned. The campaign is called "Make the Switch" and the ads are running on the Internet, TV and radio, featuring adults who currently smoke.
But some medical professionals are questioning the ads, asking if the ads imply that Juul can help people stop using cigarettes.
"If you're going to make a medical claim, we have laws about that," said Dr. Michael Ong, of the CA Tobacco Education & Research Oversight Committee.
Ong says those laws would require clinical testing that vaping products haven't been subjected to. Ong says he thinks it's walking a fine line.
"I do think that it's problematic and that it does need more scrutiny to be determined is this truly a medical claim or not," he said.
In a statement to the NBC4 I-Team, Juul said it's "a switching product" and "not intended to be used as cessation products, including for the cure or treatment of nicotine addiction ..."
Medical professionals aren't the only ones raising their eyebrow at these new ads. It's been decades since commercials aired featuring characters like the Marlboro Man.
The ads were banned from TV and radio more than 30 years ago, under the Public Health Cigarette Smoking Act.
"Probably about 70 or 80 percent of people alive today in America have probably never seen a tobacco ad on television," said Dr. Stanton Glantz, of the Center for Tobacco Control Research & Education.
Glantz says the law hasn't caught up with technology.
"The definition of a cigarette is tobacco wrapped in paper," he said. "And Juul is not a cigarette. That means these ads are fair game."
They've been effective.
Juul is currently worth nearly $40 billion, getting a big financial boost at the end of last year from Altria, the makers or Marlboro.
"I think Juul's future really depends on what the public and the public health authorities do," Glantz said. "I think left unrestrained they're going to spread all over the world very quickly and they're gonna make a ton of money."