(CNN) Facing pressure from regulators over an epidemic of youth vaping, e-cigarette giant Juul announced in late 2018 that it would stop selling certain flavors in US stores, including "fruit" and "mango."
But a new study from the American Cancer Society, looking at the critical months that followed, found that other flavors sold by Juul at the time -- mint and menthol -- quickly dominated the e-cigarette market.
Juul's decision to remove some flavors from US stores, made voluntarily in November of 2018, did seem to affect the market at large. Fruit-flavored products, which made up 33% of total e-cigarette sales before Juul's decision, dropped to just 9% of sales by April of the following year.
But sales of menthol and mint products surged, from 33% of the market in November to more than 62% of the market in April. And Juul captured all of that growth, according to the study, which looked at data from Nielsen, an analytics company.
The overall market for mint and menthol products, at least in retail channels tracked by Nielsen, grew over that period from about $95.5 million to a whopping $209.5 million per month.
Sales of tobacco-flavored products rose too, from around 17% of the market to 22% of the market. Juul captured 91% of that growth, according to the study, which was published Thursday in the American Journal of Public Health.
With federal regulation looming, Juul announced in November of 2019 that it would stop selling mint pods in the US, too. But the company continued to sell menthol products.
And while the US Food and Drug Administration essentially banned mint-flavored products a few months later, in January, the agency carved out an exception. Menthol products, which have hints of tobacco, could still be sold.
Alongside "Classic Tobacco" and "Virginia Tobacco," Juul continues to sell their menthol pods today.
Critics argue there is little difference between menthol and the now-discontinued mint, both of which risk enticing young users.
Although the company stopped selling fruity products in the US, researchers found that fruit-flavored sales overall still increased between April and September of 2019, when they came to encompass 15.8% of the market.
Other companies -- namely a brand called NJOY -- picked up where Juul had left off on fruity flavors, according to researchers. Following the FDA's new rules, NJOY is no longer selling fruit-flavored products, but the company does still offer menthol.
Alex Liber, a senior scientist with the Economic and Health Policy Research program at the American Cancer Society, said one finding from the study is that "companies' attempts to self-impose their own restrictions are unlikely to improve public health."
Even though Juul had voluntarily taken fruit-flavored products off the market, that was "quickly offset by a combination of increased fruit-flavored sales by JUUL's competitors and increased sales of other flavors—notably, mint/menthol—by JUUL," said Liber.
It is highly unlikely, he added, that youth vaping overall declined after Juul pulled some flavors but not others.
The impact on Juul sales was "short-lived," Liber said, and the market saw "the rapid recovery of flavored cartridge sales within the very retail channels that should have seen the largest declines from JUUL's actions."
Juul continues to sell a range of flavors -- including fruit and mint-flavored products -- in other countries.
Many experts argue that the company's slick, potent products fueled an epidemic of youth vaping, but Juul has long said that its customer base is adult smokers.
In a statement, the company said it doesn't intend to attract underage users, and will continue to "seek to earn the trust of society" by working with regulators and public health officials.