An experimental anti-nicotine drug appears to help people quit vaping, a new study says.

Cytisinicline is a naturally occurring plant-based substance that binds to nicotine receptors in the brain, reducing a person’s cravings, researchers said.

The drug has been shown effective in helping people quit smoking, even though it’s not yet approved by the U.S. Food and Drug Administration (FDA).

Now, new clinical trial results show that vapers taking cytisinicline tablets were more than twice as likely to successfully stop using e-cigarettes after 9 to 12 weeks.

“No medication has been approved by the FDA for vaping cessation in the United States,” said lead researcher Dr. Nancy Rigotti, director of Massachusetts General Hospital’s Tobacco Research and Treatment Center. “Our study indicates that cytisinicline might be an option to fill this gap and help adult vapers to stop using e-cigarettes.”

About 11 million U.S. adults use nicotine-laced e-cigarettes, and about half want to stop but are too hooked to quit.

For the clinical trial, 160 adults who vape nicotine but don’t smoke were randomly assigned to take cytisinicline or a placebo for 12 weeks, along with support therapy to quit.

Nearly 32% of those taking cytisinicline had successfully quit by the end of the trial, compared with 15% of those taking a placebo.

The results jibe with those of earlier trials that tested the drug’s ability to help people quit smoking, researchers said.

“The results of our study need to be confirmed in a larger trial with longer follow-up, but they are promising,” Rigotti said in a news release.

The new clinical trial results were published May 6 in JAMA Internal Medicine.