Convenience stores and gas stations will effectively be banned from selling most flavored e-cigarettes under restrictions issued Wednesday by the Food and Drug Administration.

The new directives for retailers and manufacturers, first proposed by the FDA in November, are aimed at limiting access to the e-cigarette flavors most popular among children and teens, whose use of the devices surged last year. Market leader Juul Labs Inc. sells nicotine liquids in flavors such as mango and cucumber. Others sell strawberry shortcake, gummy bear and cotton candy flavors.

“This is a real tipping point,” said FDA chief Scott Gottlieb, who plans to step down sometime over the next month. If underage vaping continues to increase, he said, the agency later this year could consider pulling pod-based vaporizers such as Juul’s from the market altogether.

Under the proposed restrictions, expected to be finalized and implemented within the next few months, bricks-and-mortar stores will be barred from selling e-cigarettes in flavors other than tobacco, mint and menthol unless they prevent minors from entering the store altogether or create a separate section of the store that minors can’t enter. Meanwhile, websites that sell flavored vaping products must curb bulk purchases and use third-party age-verification services.

“The government should not be picking winners and losers in the market,” said Jeff Lenard, a spokesman for the National Association of Convenience Stores, an industry group. “FDA’s own data shows that 86% of students who used e-cigarettes did not get them from stores—they came from online retailers or a social source.”